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2024-12-05Revert "cgroup: Fix memory leak caused by missing cgroup_bpf_offline"Chen Ridong
[ Upstream commit feb301c60970bd2a1310a53ce2d6e4375397a51b ] This reverts commit 04f8ef5643bcd8bcde25dfdebef998aea480b2ba. Only cgroup v2 can be attached by cgroup by BPF programs. Revert this commit and cgroup_bpf_inherit and cgroup_bpf_offline won't be called in cgroup v1. The memory leak issue will be fixed with next patch. Fixes: 04f8ef5643bc ("cgroup: Fix memory leak caused by missing cgroup_bpf_offline") Link: https://lore.kernel.org/cgroups/aka2hk5jsel5zomucpwlxsej6iwnfw4qu5jkrmjhyfhesjlfdw@46zxhg5bdnr7/ Signed-off-by: Chen Ridong <chenridong@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05sched/ext: Remove sched_fork() hackThomas Gleixner
[ Upstream commit 0f0d1b8e5010bfe1feeb4d78d137e41946a5370d ] Instead of solving the underlying problem of the double invocation of __sched_fork() for idle tasks, sched-ext decided to hack around the issue by partially clearing out the entity struct to preserve the already enqueued node. A provided analysis and solution has been ignored for four months. Now that someone else has taken care of cleaning it up, remove the disgusting hack and clear out the full structure. Remove the comment in the structure declaration as well, as there is no requirement for @node being the last element anymore. Fixes: f0e1a0643a59 ("sched_ext: Implement BPF extensible scheduler class") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/87ldy82wkc.ffs@tglx Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05timers: Add missing READ_ONCE() in __run_timer_base()Thomas Gleixner
[ Upstream commit 1d4199cbbe95efaba51304cfd844bd0ccd224e61 ] __run_timer_base() checks base::next_expiry without holding base::lock. That can race with a remote CPU updating next_expiry under the lock. This is an intentional and harmless data race, but lacks a READ_ONCE(), so KCSAN complains about this. Add the missing READ_ONCE(). All other places are covered already. Fixes: 79f8b28e85f8 ("timers: Annotate possible non critical data race of next_expiry") Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/all/87a5emyqk0.ffs@tglx Closes: https://lore.kernel.org/oe-lkp/202410301205.ef8e9743-lkp@intel.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05time: Fix references to _msecs_to_jiffies() handling of valuesMiguel Ojeda
[ Upstream commit 92b043fd995a63a57aae29ff85a39b6f30cd440c ] The details about the handling of the "normal" values were moved to the _msecs_to_jiffies() helpers in commit ca42aaf0c861 ("time: Refactor msecs_to_jiffies"). However, the same commit still mentioned __msecs_to_jiffies() in the added documentation. Thus point to _msecs_to_jiffies() instead. Fixes: ca42aaf0c861 ("time: Refactor msecs_to_jiffies") Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20241025110141.157205-2-ojeda@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05time: Partially revert cleanup on msecs_to_jiffies() documentationMiguel Ojeda
[ Upstream commit b05aefc1f5886c8aece650c9c1639c87b976191a ] The documentation's intention is to compare msecs_to_jiffies() (first sentence) with __msecs_to_jiffies() (second sentence), which is what the original documentation did. One of the cleanups in commit f3cb80804b82 ("time: Fix various kernel-doc problems") may have thought the paragraph was talking about the latter since that is what it is being documented. Thus revert that part of the change. Fixes: f3cb80804b82 ("time: Fix various kernel-doc problems") Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20241025110141.157205-1-ojeda@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05rcuscale: Do a proper cleanup if kfree_scale_init() failsUladzislau Rezki (Sony)
[ Upstream commit 812a1c3b9f7c36d9255f0d29d0a3d324e2f52321 ] A static analyzer for C, Smatch, reports and triggers below warnings: kernel/rcu/rcuscale.c:1215 rcu_scale_init() warn: inconsistent returns 'global &fullstop_mutex'. The checker complains about, we do not unlock the "fullstop_mutex" mutex, in case of hitting below error path: <snip> ... if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start < 2 * HZ)) { pr_alert("ERROR: call_rcu() CBs are not being lazy as expected!\n"); WARN_ON_ONCE(1); return -1; ^^^^^^^^^^ ... <snip> it happens because "-1" is returned right away instead of doing a proper unwinding. Fix it by jumping to "unwind" label instead of returning -1. Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com> Closes: https://lore.kernel.org/rcu/ZxfTrHuEGtgnOYWp@pc636/T/ Fixes: 084e04fff160 ("rcuscale: Add laziness and kfree tests") Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05rcu/nocb: Fix missed RCU barrier on deoffloadingZqiang
[ Upstream commit 2996980e20b7a54a1869df15b3445374b850b155 ] Currently, running rcutorture test with torture_type=rcu fwd_progress=8 n_barrier_cbs=8 nocbs_nthreads=8 nocbs_toggle=100 onoff_interval=60 test_boost=2, will trigger the following warning: WARNING: CPU: 19 PID: 100 at kernel/rcu/tree_nocb.h:1061 rcu_nocb_rdp_deoffload+0x292/0x2a0 RIP: 0010:rcu_nocb_rdp_deoffload+0x292/0x2a0 Call Trace: <TASK> ? __warn+0x7e/0x120 ? rcu_nocb_rdp_deoffload+0x292/0x2a0 ? report_bug+0x18e/0x1a0 ? handle_bug+0x3d/0x70 ? exc_invalid_op+0x18/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? rcu_nocb_rdp_deoffload+0x292/0x2a0 rcu_nocb_cpu_deoffload+0x70/0xa0 rcu_nocb_toggle+0x136/0x1c0 ? __pfx_rcu_nocb_toggle+0x10/0x10 kthread+0xd1/0x100 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2f/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> CPU0 CPU2 CPU3 //rcu_nocb_toggle //nocb_cb_wait //rcutorture // deoffload CPU1 // process CPU1's rdp rcu_barrier() rcu_segcblist_entrain() rcu_segcblist_add_len(1); // len == 2 // enqueue barrier // callback to CPU1's // rdp->cblist rcu_do_batch() // invoke CPU1's rdp->cblist // callback rcu_barrier_callback() rcu_barrier() mutex_lock(&rcu_state.barrier_mutex); // still see len == 2 // enqueue barrier callback // to CPU1's rdp->cblist rcu_segcblist_entrain() rcu_segcblist_add_len(1); // len == 3 // decrement len rcu_segcblist_add_len(-2); kthread_parkme() // CPU1's rdp->cblist len == 1 // Warn because there is // still a pending barrier // trigger warning WARN_ON_ONCE(rcu_segcblist_n_cbs(&rdp->cblist)); cpus_read_unlock(); // wait CPU1 to comes online and // invoke barrier callback on // CPU1 rdp's->cblist wait_for_completion(&rcu_state.barrier_completion); // deoffload CPU4 cpus_read_lock() rcu_barrier() mutex_lock(&rcu_state.barrier_mutex); // block on barrier_mutex // wait rcu_barrier() on // CPU3 to unlock barrier_mutex // but CPU3 unlock barrier_mutex // need to wait CPU1 comes online // when CPU1 going online will block on cpus_write_lock The above scenario will not only trigger a WARN_ON_ONCE(), but also trigger a deadlock. Thanks to nocb locking, a second racing rcu_barrier() on an offline CPU will either observe the decremented callback counter down to 0 and spare the callback enqueue, or rcuo will observe the new callback and keep rdp->nocb_cb_sleep to false. Therefore check rdp->nocb_cb_sleep before parking to make sure no further rcu_barrier() is waiting on the rdp. Fixes: 1fcb932c8b5c ("rcu/nocb: Simplify (de-)offloading state machine") Suggested-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Zqiang <qiang.zhang1211@gmail.com> Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05rcu/kvfree: Fix data-race in __mod_timer / kvfree_call_rcuUladzislau Rezki (Sony)
[ Upstream commit a23da88c6c80e41e0503e0b481a22c9eea63f263 ] KCSAN reports a data race when access the krcp->monitor_work.timer.expires variable in the schedule_delayed_monitor_work() function: <snip> BUG: KCSAN: data-race in __mod_timer / kvfree_call_rcu read to 0xffff888237d1cce8 of 8 bytes by task 10149 on cpu 1: schedule_delayed_monitor_work kernel/rcu/tree.c:3520 [inline] kvfree_call_rcu+0x3b8/0x510 kernel/rcu/tree.c:3839 trie_update_elem+0x47c/0x620 kernel/bpf/lpm_trie.c:441 bpf_map_update_value+0x324/0x350 kernel/bpf/syscall.c:203 generic_map_update_batch+0x401/0x520 kernel/bpf/syscall.c:1849 bpf_map_do_batch+0x28c/0x3f0 kernel/bpf/syscall.c:5143 __sys_bpf+0x2e5/0x7a0 __do_sys_bpf kernel/bpf/syscall.c:5741 [inline] __se_sys_bpf kernel/bpf/syscall.c:5739 [inline] __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5739 x64_sys_call+0x2625/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:322 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f write to 0xffff888237d1cce8 of 8 bytes by task 56 on cpu 0: __mod_timer+0x578/0x7f0 kernel/time/timer.c:1173 add_timer_global+0x51/0x70 kernel/time/timer.c:1330 __queue_delayed_work+0x127/0x1a0 kernel/workqueue.c:2523 queue_delayed_work_on+0xdf/0x190 kernel/workqueue.c:2552 queue_delayed_work include/linux/workqueue.h:677 [inline] schedule_delayed_monitor_work kernel/rcu/tree.c:3525 [inline] kfree_rcu_monitor+0x5e8/0x660 kernel/rcu/tree.c:3643 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3310 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3391 kthread+0x1d1/0x210 kernel/kthread.c:389 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 56 Comm: kworker/u8:4 Not tainted 6.12.0-rc2-syzkaller-00050-g5b7c893ed5ed #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events_unbound kfree_rcu_monitor <snip> kfree_rcu_monitor() rearms the work if a "krcp" has to be still offloaded and this is done without holding krcp->lock, whereas the kvfree_call_rcu() holds it. Fix it by acquiring the "krcp->lock" for kfree_rcu_monitor() so both functions do not race anymore. Reported-by: syzbot+061d370693bdd99f9d34@syzkaller.appspotmail.com Link: https://lore.kernel.org/lkml/ZxZ68KmHDQYU0yfD@pc636/T/ Fixes: 8fc5494ad5fa ("rcu/kvfree: Move need_offload_krc() out of krcp->lock") Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05rcu/srcutiny: don't return before reenabling preemptionMichal Schmidt
[ Upstream commit 0ea3acbc804c2d5a165442cdf9c0526f4d324888 ] Code after the return statement is dead. Enable preemption before returning from srcu_drive_gp(). This will be important when/if PREEMPT_AUTO (lazy resched) gets merged. Fixes: 65b4a59557f6 ("srcu: Make Tiny SRCU explicitly disable preemption") Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Michal Schmidt <mschmidt@redhat.com> Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05sched/cpufreq: Ensure sd is rebuilt for EAS checkChristian Loehle
[ Upstream commit 70d8b6485b0bcd135b6699fc4252d2272818d1fb ] Ensure sugov_eas_rebuild_sd() is always called when sugov_init() succeeds. The out goto initialized sugov without forcing the rebuild. Previously the missing call to sugov_eas_rebuild_sd() could lead to EAS not being enabled on boot when it should have been, because it requires all policies to be controlled by schedutil while they might not have been initialized yet. Fixes: e7a1b32e43b1 ("cpufreq: Rebuild sched-domains when removing cpufreq driver") Signed-off-by: Christian Loehle <christian.loehle@arm.com> Link: https://patch.msgid.link/35e572d9-1152-406a-9e34-2525f7548af9@arm.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-16Merge tag 'mm-hotfixes-stable-2024-11-16-15-33' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull hotfixes from Andrew Morton: "10 hotfixes, 7 of which are cc:stable. All singletons, please see the changelogs for details" * tag 'mm-hotfixes-stable-2024-11-16-15-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mm: revert "mm: shmem: fix data-race in shmem_getattr()" ocfs2: uncache inode which has failed entering the group mm: fix NULL pointer dereference in alloc_pages_bulk_noprof mm, doc: update read_ahead_kb for MADV_HUGEPAGE fs/proc/task_mmu: prevent integer overflow in pagemap_scan_get_args() sched/task_stack: fix object_is_on_stack() for KASAN tagged pointers crash, powerpc: default to CRASH_DUMP=n on PPC_BOOK3S_32 mm/mremap: fix address wraparound in move_page_tables() tools/mm: fix compile error mm, swap: fix allocation and scanning race with swapoff
2024-11-16Merge tag 'trace-ringbuffer-v6.12-rc7-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull ring buffer fixes from Steven Rostedt: - Revert: "ring-buffer: Do not have boot mapped buffers hook to CPU hotplug" A crash that happened on cpu hotplug was actually caused by the incorrect ref counting that was fixed by commit 2cf9733891a4 ("ring-buffer: Fix refcount setting of boot mapped buffers"). The removal of calling cpu hotplug callbacks on memory mapped buffers was not an issue even though the tests at the time pointed toward it. But in fact, there's a check in that code that tests to see if the buffers are already allocated or not, and will not allocate them again if they are. Not calling the cpu hotplug callbacks ended up not initializing the non boot CPU buffers. Simply remove that change. - Clear all CPU buffers when starting tracing in a boot mapped buffer To properly process events from a previous boot, the address space needs to be accounted for due to KASLR and the events in the buffer are updated accordingly when read. This also requires that when the buffer has tracing enabled again in the current boot that the buffers are reset so that events from the previous boot do not interact with the events of the current boot and cause confusing due to not having the proper meta data. It was found that if a CPU is taken offline, that its per CPU buffer is not reset when tracing starts. This allows for events to be from both the previous boot and the current boot to be in the buffer at the same time. Clear all CPU buffers when tracing is started in a boot mapped buffer. * tag 'trace-ringbuffer-v6.12-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/ring-buffer: Clear all memory mapped CPU ring buffers on first recording Revert: "ring-buffer: Do not have boot mapped buffers hook to CPU hotplug"
2024-11-15Merge tag 'sched_ext-for-6.12-rc7-fixes-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext Pull sched_ext fix from Tejun Heo: "One more fix for v6.12-rc7 ops.cpu_acquire() was being invoked with the wrong kfunc mask allowing the operation to call kfuncs which shouldn't be allowed. Fix it by using SCX_KF_REST instead, which is trivial and low risk" * tag 'sched_ext-for-6.12-rc7-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: sched_ext: ops.cpu_acquire() should be called with SCX_KF_REST
2024-11-14crash, powerpc: default to CRASH_DUMP=n on PPC_BOOK3S_32Dave Vasilevsky
Fixes boot failures on 6.9 on PPC_BOOK3S_32 machines using Open Firmware. On these machines, the kernel refuses to boot from non-zero PHYSICAL_START, which occurs when CRASH_DUMP is on. Since most PPC_BOOK3S_32 machines boot via Open Firmware, it should default to off for them. Users booting via some other mechanism can still turn it on explicitly. Does not change the default on any other architectures for the time being. Link: https://lkml.kernel.org/r/20240917163720.1644584-1-dave@vasilevsky.ca Fixes: 75bc255a7444 ("crash: clean up kdump related config items") Signed-off-by: Dave Vasilevsky <dave@vasilevsky.ca> Reported-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de> Closes: https://lists.debian.org/debian-powerpc/2024/07/msg00001.html Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Acked-by: Baoquan He <bhe@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Reimar Döffinger <Reimar.Doeffinger@gmx.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-14sched_ext: ops.cpu_acquire() should be called with SCX_KF_RESTTejun Heo
ops.cpu_acquire() is currently called with 0 kf_maks which is interpreted as SCX_KF_UNLOCKED which allows all unlocked kfuncs, but ops.cpu_acquire() is called from balance_one() under the rq lock and should only be allowed call kfuncs that are safe under the rq lock. Update it to use SCX_KF_REST. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: David Vernet <void@manifault.com> Cc: Zhao Mengmeng <zhaomzhao@126.com> Link: http://lkml.kernel.org/r/ZzYvf2L3rlmjuKzh@slm.duckdns.org Fixes: 245254f7081d ("sched_ext: Implement sched_ext_ops.cpu_acquire/release()")
2024-11-14tracing/ring-buffer: Clear all memory mapped CPU ring buffers on first recordingSteven Rostedt
The events of a memory mapped ring buffer from the previous boot should not be mixed in with events from the current boot. There's meta data that is used to handle KASLR so that function names can be shown properly. Also, since the timestamps of the previous boot have no meaning to the timestamps of the current boot, having them intermingled in a buffer can also cause confusion because there could possibly be events in the future. When a trace is activated the meta data is reset so that the pointers of are now processed for the new address space. The trace buffers are reset when tracing starts for the first time. The problem here is that the reset only happens on online CPUs. If a CPU is offline, it does not get reset. To demonstrate the issue, a previous boot had tracing enabled in the boot mapped ring buffer on reboot. On the following boot, tracing has not been started yet so the function trace from the previous boot is still visible. # trace-cmd show -B boot_mapped -c 3 | tail <idle>-0 [003] d.h2. 156.462395: __rcu_read_lock <-cpu_emergency_disable_virtualization <idle>-0 [003] d.h2. 156.462396: vmx_emergency_disable_virtualization_cpu <-cpu_emergency_disable_virtualization <idle>-0 [003] d.h2. 156.462396: __rcu_read_unlock <-__sysvec_reboot <idle>-0 [003] d.h2. 156.462397: stop_this_cpu <-__sysvec_reboot <idle>-0 [003] d.h2. 156.462397: set_cpu_online <-stop_this_cpu <idle>-0 [003] d.h2. 156.462397: disable_local_APIC <-stop_this_cpu <idle>-0 [003] d.h2. 156.462398: clear_local_APIC <-disable_local_APIC <idle>-0 [003] d.h2. 156.462574: mcheck_cpu_clear <-stop_this_cpu <idle>-0 [003] d.h2. 156.462575: mce_intel_feature_clear <-stop_this_cpu <idle>-0 [003] d.h2. 156.462575: lmce_supported <-mce_intel_feature_clear Now, if CPU 3 is taken offline, and tracing is started on the memory mapped ring buffer, the events from the previous boot in the CPU 3 ring buffer is not reset. Now those events are using the meta data from the current boot and produces just hex values. # echo 0 > /sys/devices/system/cpu/cpu3/online # trace-cmd start -B boot_mapped -p function # trace-cmd show -B boot_mapped -c 3 | tail <idle>-0 [003] d.h2. 156.462395: 0xffffffff9a1e3194 <-0xffffffff9a0f655e <idle>-0 [003] d.h2. 156.462396: 0xffffffff9a0a1d24 <-0xffffffff9a0f656f <idle>-0 [003] d.h2. 156.462396: 0xffffffff9a1e6bc4 <-0xffffffff9a0f7323 <idle>-0 [003] d.h2. 156.462397: 0xffffffff9a0d12b4 <-0xffffffff9a0f732a <idle>-0 [003] d.h2. 156.462397: 0xffffffff9a1458d4 <-0xffffffff9a0d12e2 <idle>-0 [003] d.h2. 156.462397: 0xffffffff9a0faed4 <-0xffffffff9a0d12e7 <idle>-0 [003] d.h2. 156.462398: 0xffffffff9a0faaf4 <-0xffffffff9a0faef2 <idle>-0 [003] d.h2. 156.462574: 0xffffffff9a0e3444 <-0xffffffff9a0d12ef <idle>-0 [003] d.h2. 156.462575: 0xffffffff9a0e4964 <-0xffffffff9a0d12ef <idle>-0 [003] d.h2. 156.462575: 0xffffffff9a0e3fb0 <-0xffffffff9a0e496f Reset all CPUs when starting a boot mapped ring buffer for the first time, and not just the online CPUs. Fixes: 7a1d1e4b9639f ("tracing/ring-buffer: Add last_boot_info file to boot instance") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-11-14Revert: "ring-buffer: Do not have boot mapped buffers hook to CPU hotplug"Steven Rostedt
A crash happened when testing cpu hotplug with respect to the memory mapped ring buffers. It was assumed that the hot plug code was adding a per CPU buffer that was already created that caused the crash. The real problem was due to ref counting and was fixed by commit 2cf9733891a4 ("ring-buffer: Fix refcount setting of boot mapped buffers"). When a per CPU buffer is created, it will not be created again even with CPU hotplug, so the fix to not use CPU hotplug was a red herring. In fact, it caused only the boot CPU buffer to be created, leaving the other CPU per CPU buffers disabled. Revert that change as it was not the culprit of the fix it was intended to be. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20241113230839.6c03640f@gandalf.local.home Fixes: 912da2c384d5 ("ring-buffer: Do not have boot mapped buffers hook to CPU hotplug") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-11-11Merge tag 'sched_ext-for-6.12-rc7-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext Pull sched_ext fixes from Tejun Heo: - The fair sched class currently has a bug where its balance() returns true telling the sched core that it has tasks to run but then NULL from pick_task(). This makes sched core call sched_ext's pick_task() without preceding balance() which can lead to stalls in partial mode. For now, work around by detecting the condition and forcing the CPU to go through another scheduling cycle. - Add a missing newline to an error message and fix drgn introspection tool which went out of sync. * tag 'sched_ext-for-6.12-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: sched_ext: Handle cases where pick_task_scx() is called without preceding balance_scx() sched_ext: Update scx_show_state.py to match scx_ops_bypass_depth's new type sched_ext: Add a missing newline at the end of an error message
2024-11-10Merge tag 'mm-hotfixes-stable-2024-11-09-22-40' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull misc fixes from Andrew Morton: "20 hotfixes, 14 of which are cc:stable. Three affect DAMON. Lorenzo's five-patch series to address the mmap_region error handling is here also. Apart from that, various singletons" * tag 'mm-hotfixes-stable-2024-11-09-22-40' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mailmap: add entry for Thorsten Blum ocfs2: remove entry once instead of null-ptr-dereference in ocfs2_xa_remove() signal: restore the override_rlimit logic fs/proc: fix compile warning about variable 'vmcore_mmap_ops' ucounts: fix counter leak in inc_rlimit_get_ucounts() selftests: hugetlb_dio: check for initial conditions to skip in the start mm: fix docs for the kernel parameter ``thp_anon=`` mm/damon/core: avoid overflow in damon_feed_loop_next_input() mm/damon/core: handle zero schemes apply interval mm/damon/core: handle zero {aggregation,ops_update} intervals mm/mlock: set the correct prev on failure objpool: fix to make percpu slot allocation more robust mm/page_alloc: keep track of free highatomic mm: resolve faulty mmap_region() error path behaviour mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling mm: refactor map_deny_write_exec() mm: unconditionally close VMAs on error mm: avoid unsafe VMA hook invocation when error arises on mmap hook mm/thp: fix deferred split unqueue naming and locking mm/thp: fix deferred split queue not partially_mapped
2024-11-09sched_ext: Handle cases where pick_task_scx() is called without preceding ↵Tejun Heo
balance_scx() sched_ext dispatches tasks from the BPF scheduler from balance_scx() and thus every pick_task_scx() call must be preceded by balance_scx(). While this usually holds, due to a bug, there are cases where the fair class's balance() returns true indicating that it has tasks to run on the CPU and thus terminating balance() calls but fails to actually find the next task to run when pick_task() is called. In such cases, pick_task_scx() can be called without preceding balance_scx(). Detect this condition using SCX_RQ_BAL_PENDING flags. If detected, keep running the previous task if possible and avoid stalling from entering idle without balancing. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/Ztj_h5c2LYsdXYbA@slm.duckdns.org
2024-11-07signal: restore the override_rlimit logicRoman Gushchin
Prior to commit d64696905554 ("Reimplement RLIMIT_SIGPENDING on top of ucounts") UCOUNT_RLIMIT_SIGPENDING rlimit was not enforced for a class of signals. However now it's enforced unconditionally, even if override_rlimit is set. This behavior change caused production issues. For example, if the limit is reached and a process receives a SIGSEGV signal, sigqueue_alloc fails to allocate the necessary resources for the signal delivery, preventing the signal from being delivered with siginfo. This prevents the process from correctly identifying the fault address and handling the error. From the user-space perspective, applications are unaware that the limit has been reached and that the siginfo is effectively 'corrupted'. This can lead to unpredictable behavior and crashes, as we observed with java applications. Fix this by passing override_rlimit into inc_rlimit_get_ucounts() and skip the comparison to max there if override_rlimit is set. This effectively restores the old behavior. Link: https://lkml.kernel.org/r/20241104195419.3962584-1-roman.gushchin@linux.dev Fixes: d64696905554 ("Reimplement RLIMIT_SIGPENDING on top of ucounts") Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Co-developed-by: Andrei Vagin <avagin@google.com> Signed-off-by: Andrei Vagin <avagin@google.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Alexey Gladkov <legion@kernel.org> Cc: Kees Cook <kees@kernel.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-07ucounts: fix counter leak in inc_rlimit_get_ucounts()Andrei Vagin
The inc_rlimit_get_ucounts() increments the specified rlimit counter and then checks its limit. If the value exceeds the limit, the function returns an error without decrementing the counter. Link: https://lkml.kernel.org/r/20241101191940.3211128-1-roman.gushchin@linux.dev Fixes: 15bc01effefe ("ucounts: Fix signal ucount refcounting") Signed-off-by: Andrei Vagin <avagin@google.com> Co-developed-by: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Tested-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Alexey Gladkov <legion@kernel.org> Cc: Kees Cook <kees@kernel.org> Cc: Andrei Vagin <avagin@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexey Gladkov <legion@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-06Merge tag 'tracefs-v6.12-rc6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracefs fixes from Steven Rostedt: "Fix tracefs mount options. Commit 78ff64081949 ("vfs: Convert tracefs to use the new mount API") broke the gid setting when set by fstab or other mount utility. It is ignored when it is set. Fix the code so that it recognises the option again and will honor the settings on mount at boot up. Update the internal documentation and create a selftest to make sure it doesn't break again in the future" * tag 'tracefs-v6.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/selftests: Add tracefs mount options test tracing: Document tracefs gid mount option tracing: Fix tracefs mount options
2024-11-05sched_ext: Add a missing newline at the end of an error messageTejun Heo
Signed-off-by: Tejun Heo <tj@kernel.org>
2024-11-03Merge tag 'timers-urgent-2024-11-03' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fix from Thomas Gleixner: "A single fix for posix CPU timers. When a thread is cloned, the posix CPU timers are not inherited. If the parent has a CPU timer armed the corresponding tick dependency in the tasks tick_dep_mask is set and copied to the new thread, which means the new thread and all decendants will prevent the system to go into full NOHZ operation. Clear the tick dependency mask in copy_process() to fix this" * tag 'timers-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: posix-cpu-timers: Clear TICK_DEP_BIT_POSIX_TIMER on clone
2024-11-03Merge tag 'sched-urgent-2024-11-03' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Thomas Gleixner: - Plug a race between pick_next_task_fair() and try_to_wake_up() where both try to write to the same task, even though both paths hold a runqueue lock, but obviously from different runqueues. The problem is that the store to task::on_rq in __block_task() is visible to try_to_wake_up() which assumes that the task is not queued. Both sides then operate on the same task. Cure it by rearranging __block_task() so the the store to task::on_rq is the last operation on the task. - Prevent a potential NULL pointer dereference in task_numa_work() task_numa_work() iterates the VMAs of a process. A concurrent unmap of the address space can result in a NULL pointer return from vma_next() which is unchecked. Add the missing NULL pointer check to prevent this. - Operate on the correct scheduler policy in task_should_scx() task_should_scx() returns true when a task should be handled by sched EXT. It checks the tasks scheduling policy. This fails when the check is done before a policy has been set. Cure it by handing the policy into task_should_scx() so it operates on the requested value. - Add the missing handling of sched EXT in the delayed dequeue mechanism. This was simply forgotten. * tag 'sched-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/ext: Fix scx vs sched_delayed sched: Pass correct scheduling policy to __setscheduler_class sched/numa: Fix the potential null pointer dereference in task_numa_work() sched: Fix pick_next_task_fair() vs try_to_wake_up() race
2024-11-03Merge tag 'perf-urgent-2024-11-03' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fix from Thomas Gleixner: "perf_event_clear_cpumask() uses list_for_each_entry_rcu() without being in a RCU read side critical section, which triggers a 'suspicious RCU usage' warning. It turns out that the list walk does not be RCU protected because the write side lock is held in this context. Change it to a regular list walk" * tag 'perf-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Fix missing RCU reader protection in perf_event_clear_cpumask()
2024-11-03Merge tag 'irq-urgent-2024-11-03' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq fixes from Thomas Gleixner: - Fix an off-by-one error in the failure path of msi_domain_alloc(), which causes the cleanup loop to terminate early and leaking the first allocated interrupt. - Handle a corner case in GIC-V4 versus a lazily mapped Virtual Processing Element (VPE). If the VPE has not been mapped because the guest has not yet emitted a mapping command, then the set_affinity() callback returns an error code, which causes the vCPU management to fail. Return success in this case without touching the hardware. This will be done later when the guest issues the mapping command. * tag 'irq-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip/gic-v4: Correctly deal with set_affinity on lazily-mapped VPEs genirq/msi: Fix off-by-one error in msi_domain_alloc()
2024-11-01tracing: Document tracefs gid mount optionKalesh Singh
Commit ee7f3666995d ("tracefs: Have new files inherit the ownership of their parent") and commit 48b27b6b5191 ("tracefs: Set all files to the same group ownership as the mount option") introduced a new gid mount option that allows specifying a group to apply to all entries in tracefs. Document this in the tracing readme. Cc: Eric Sandeen <sandeen@redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Ali Zahraee <ahzahraee@gmail.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Howells <dhowells@redhat.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lore.kernel.org/20241030171928.4168869-3-kaleshsingh@google.com Signed-off-by: Kalesh Singh <kaleshsingh@google.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-31Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfLinus Torvalds
Pull bpf fixes from Daniel Borkmann: - Fix BPF verifier to force a checkpoint when the program's jump history becomes too long (Eduard Zingerman) - Add several fixes to the BPF bits iterator addressing issues like memory leaks and overflow problems (Hou Tao) - Fix an out-of-bounds write in trie_get_next_key (Byeonguk Jeong) - Fix BPF test infra's LIVE_FRAME frame update after a page has been recycled (Toke Høiland-Jørgensen) - Fix BPF verifier and undo the 40-bytes extra stack space for bpf_fastcall patterns due to various bugs (Eduard Zingerman) - Fix a BPF sockmap race condition which could trigger a NULL pointer dereference in sock_map_link_update_prog (Cong Wang) - Fix tcp_bpf_recvmsg_parser to retrieve seq_copied from tcp_sk under the socket lock (Jiayuan Chen) * tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: bpf, test_run: Fix LIVE_FRAME frame update after a page has been recycled selftests/bpf: Add three test cases for bits_iter bpf: Use __u64 to save the bits in bits iterator bpf: Check the validity of nr_words in bpf_iter_bits_new() bpf: Add bpf_mem_alloc_check_size() helper bpf: Free dynamically allocated bits in bpf_iter_bits_destroy() bpf: disallow 40-bytes extra stack for bpf_fastcall patterns selftests/bpf: Add test for trie_get_next_key() bpf: Fix out-of-bounds write in trie_get_next_key() selftests/bpf: Test with a very short loop bpf: Force checkpoint when jmp history is too long bpf: fix filed access without lock sock_map: fix a NULL pointer dereference in sock_map_link_update_prog()
2024-10-30sched/ext: Fix scx vs sched_delayedPeter Zijlstra
Commit 98442f0ccd82 ("sched: Fix delayed_dequeue vs switched_from_fair()") forgot about scx :/ Fixes: 98442f0ccd82 ("sched: Fix delayed_dequeue vs switched_from_fair()") Reported-by: Tejun Heo <tj@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lkml.kernel.org/r/20241030104934.GK14555@noisy.programming.kicks-ass.net
2024-10-30bpf: Use __u64 to save the bits in bits iteratorHou Tao
On 32-bit hosts (e.g., arm32), when a bpf program passes a u64 to bpf_iter_bits_new(), bpf_iter_bits_new() will use bits_copy to store the content of the u64. However, bits_copy is only 4 bytes, leading to stack corruption. The straightforward solution would be to replace u64 with unsigned long in bpf_iter_bits_new(). However, this introduces confusion and problems for 32-bit hosts because the size of ulong in bpf program is 8 bytes, but it is treated as 4-bytes after passed to bpf_iter_bits_new(). Fix it by changing the type of both bits and bit_count from unsigned long to u64. However, the change is not enough. The main reason is that bpf_iter_bits_next() uses find_next_bit() to find the next bit and the pointer passed to find_next_bit() is an unsigned long pointer instead of a u64 pointer. For 32-bit little-endian host, it is fine but it is not the case for 32-bit big-endian host. Because under 32-bit big-endian host, the first iterated unsigned long will be the bits 32-63 of the u64 instead of the expected bits 0-31. Therefore, in addition to changing the type, swap the two unsigned longs within the u64 for 32-bit big-endian host. Signed-off-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/20241030100516.3633640-5-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-10-30bpf: Check the validity of nr_words in bpf_iter_bits_new()Hou Tao
Check the validity of nr_words in bpf_iter_bits_new(). Without this check, when multiplication overflow occurs for nr_bits (e.g., when nr_words = 0x0400-0001, nr_bits becomes 64), stack corruption may occur due to bpf_probe_read_kernel_common(..., nr_bytes = 0x2000-0008). Fix it by limiting the maximum value of nr_words to 511. The value is derived from the current implementation of BPF memory allocator. To ensure compatibility if the BPF memory allocator's size limitation changes in the future, use the helper bpf_mem_alloc_check_size() to check whether nr_bytes is too larger. And return -E2BIG instead of -ENOMEM for oversized nr_bytes. Fixes: 4665415975b0 ("bpf: Add bits iterator") Signed-off-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/20241030100516.3633640-4-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-10-30bpf: Add bpf_mem_alloc_check_size() helperHou Tao
Introduce bpf_mem_alloc_check_size() to check whether the allocation size exceeds the limitation for the kmalloc-equivalent allocator. The upper limit for percpu allocation is LLIST_NODE_SZ bytes larger than non-percpu allocation, so a percpu argument is added to the helper. The helper will be used in the following patch to check whether the size parameter passed to bpf_mem_alloc() is too big. Signed-off-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/20241030100516.3633640-3-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-10-30bpf: Free dynamically allocated bits in bpf_iter_bits_destroy()Hou Tao
bpf_iter_bits_destroy() uses "kit->nr_bits <= 64" to check whether the bits are dynamically allocated. However, the check is incorrect and may cause a kmemleak as shown below: unreferenced object 0xffff88812628c8c0 (size 32): comm "swapper/0", pid 1, jiffies 4294727320 hex dump (first 32 bytes): b0 c1 55 f5 81 88 ff ff f0 f0 f0 f0 f0 f0 f0 f0 ..U........... f0 f0 f0 f0 f0 f0 f0 f0 00 00 00 00 00 00 00 00 .............. backtrace (crc 781e32cc): [<00000000c452b4ab>] kmemleak_alloc+0x4b/0x80 [<0000000004e09f80>] __kmalloc_node_noprof+0x480/0x5c0 [<00000000597124d6>] __alloc.isra.0+0x89/0xb0 [<000000004ebfffcd>] alloc_bulk+0x2af/0x720 [<00000000d9c10145>] prefill_mem_cache+0x7f/0xb0 [<00000000ff9738ff>] bpf_mem_alloc_init+0x3e2/0x610 [<000000008b616eac>] bpf_global_ma_init+0x19/0x30 [<00000000fc473efc>] do_one_initcall+0xd3/0x3c0 [<00000000ec81498c>] kernel_init_freeable+0x66a/0x940 [<00000000b119f72f>] kernel_init+0x20/0x160 [<00000000f11ac9a7>] ret_from_fork+0x3c/0x70 [<0000000004671da4>] ret_from_fork_asm+0x1a/0x30 That is because nr_bits will be set as zero in bpf_iter_bits_next() after all bits have been iterated. Fix the issue by setting kit->bit to kit->nr_bits instead of setting kit->nr_bits to zero when the iteration completes in bpf_iter_bits_next(). In addition, use "!nr_bits || bits >= nr_bits" to check whether the iteration is complete and still use "nr_bits > 64" to indicate whether bits are dynamically allocated. The "!nr_bits" check is necessary because bpf_iter_bits_new() may fail before setting kit->nr_bits, and this condition will stop the iteration early instead of accessing the zeroed or freed kit->bits. Considering the initial value of kit->bits is -1 and the type of kit->nr_bits is unsigned int, change the type of kit->nr_bits to int. The potential overflow problem will be handled in the following patch. Fixes: 4665415975b0 ("bpf: Add bits iterator") Acked-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/20241030100516.3633640-2-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-10-29bpf: disallow 40-bytes extra stack for bpf_fastcall patternsEduard Zingerman
Hou Tao reported an issue with bpf_fastcall patterns allowing extra stack space above MAX_BPF_STACK limit. This extra stack allowance is not integrated properly with the following verifier parts: - backtracking logic still assumes that stack can't exceed MAX_BPF_STACK; - bpf_verifier_env->scratched_stack_slots assumes only 64 slots are available. Here is an example of an issue with precision tracking (note stack slot -8 tracked as precise instead of -520): 0: (b7) r1 = 42 ; R1_w=42 1: (b7) r2 = 42 ; R2_w=42 2: (7b) *(u64 *)(r10 -512) = r1 ; R1_w=42 R10=fp0 fp-512_w=42 3: (7b) *(u64 *)(r10 -520) = r2 ; R2_w=42 R10=fp0 fp-520_w=42 4: (85) call bpf_get_smp_processor_id#8 ; R0_w=scalar(...) 5: (79) r2 = *(u64 *)(r10 -520) ; R2_w=42 R10=fp0 fp-520_w=42 6: (79) r1 = *(u64 *)(r10 -512) ; R1_w=42 R10=fp0 fp-512_w=42 7: (bf) r3 = r10 ; R3_w=fp0 R10=fp0 8: (0f) r3 += r2 mark_precise: frame0: last_idx 8 first_idx 0 subseq_idx -1 mark_precise: frame0: regs=r2 stack= before 7: (bf) r3 = r10 mark_precise: frame0: regs=r2 stack= before 6: (79) r1 = *(u64 *)(r10 -512) mark_precise: frame0: regs=r2 stack= before 5: (79) r2 = *(u64 *)(r10 -520) mark_precise: frame0: regs= stack=-8 before 4: (85) call bpf_get_smp_processor_id#8 mark_precise: frame0: regs= stack=-8 before 3: (7b) *(u64 *)(r10 -520) = r2 mark_precise: frame0: regs=r2 stack= before 2: (7b) *(u64 *)(r10 -512) = r1 mark_precise: frame0: regs=r2 stack= before 1: (b7) r2 = 42 9: R2_w=42 R3_w=fp42 9: (95) exit This patch disables the additional allowance for the moment. Also, two test cases are removed: - bpf_fastcall_max_stack_ok: it fails w/o additional stack allowance; - bpf_fastcall_max_stack_fail: this test is no longer necessary, stack size follows regular rules, pattern invalidation is checked by other test cases. Reported-by: Hou Tao <houtao@huaweicloud.com> Closes: https://lore.kernel.org/bpf/20241023022752.172005-1-houtao@huaweicloud.com/ Fixes: 5b5f51bff1b6 ("bpf: no_caller_saved_registers attribute for helper calls") Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Tested-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/20241029193911.1575719-1-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-10-29Merge tag 'cgroup-for-6.12-rc5-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: - cgroup_bpf_release_fn() could saturate system_wq with cgrp->bpf.release_work which can then form a circular dependency leading to deadlocks. Fix by using a dedicated workqueue. The system_wq's max concurrency limit is being increased separately. - Fix theoretical off-by-one bug when enforcing max cgroup hierarchy depth * tag 'cgroup-for-6.12-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Fix potential overflow issue when checking max_depth cgroup/bpf: use a dedicated workqueue for cgroup bpf destruction
2024-10-29Merge tag 'sched_ext-for-6.12-rc5-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext Pull sched_ext fixes from Tejun Heo: - Instances of scx_ops_bypass() could race each other leading to misbehavior. Fix by protecting the operation with a spinlock. - selftest and userspace header fixes * tag 'sched_ext-for-6.12-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: sched_ext: Fix enq_last_no_enq_fails selftest sched_ext: Make cast_mask() inline scx: Fix raciness in scx_ops_bypass() scx: Fix exit selftest to use custom DSQ sched_ext: Fix function pointer type mismatches in BPF selftests selftests/sched_ext: add order-only dependency of runner.o on BPFOBJ
2024-10-29bpf: Fix out-of-bounds write in trie_get_next_key()Byeonguk Jeong
trie_get_next_key() allocates a node stack with size trie->max_prefixlen, while it writes (trie->max_prefixlen + 1) nodes to the stack when it has full paths from the root to leaves. For example, consider a trie with max_prefixlen is 8, and the nodes with key 0x00/0, 0x00/1, 0x00/2, ... 0x00/8 inserted. Subsequent calls to trie_get_next_key with _key with .prefixlen = 8 make 9 nodes be written on the node stack with size 8. Fixes: b471f2f1de8b ("bpf: implement MAP_GET_NEXT_KEY command for LPM_TRIE map") Signed-off-by: Byeonguk Jeong <jungbu2855@gmail.com> Reviewed-by: Toke Høiland-Jørgensen <toke@kernel.org> Tested-by: Hou Tao <houtao1@huawei.com> Acked-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/Zxx384ZfdlFYnz6J@localhost.localdomain Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-10-29bpf: Force checkpoint when jmp history is too longEduard Zingerman
A specifically crafted program might trick verifier into growing very long jump history within a single bpf_verifier_state instance. Very long jump history makes mark_chain_precision() unreasonably slow, especially in case if verifier processes a loop. Mitigate this by forcing new state in is_state_visited() in case if current state's jump history is too long. Use same constant as in `skip_inf_loop_check`, but multiply it by arbitrarily chosen value 2 to account for jump history containing not only information about jumps, but also information about stack access. For an example of problematic program consider the code below, w/o this patch the example is processed by verifier for ~15 minutes, before failing to allocate big-enough chunk for jmp_history. 0: r7 = *(u16 *)(r1 +0);" 1: r7 += 0x1ab064b9;" 2: if r7 & 0x702000 goto 1b; 3: r7 &= 0x1ee60e;" 4: r7 += r1;" 5: if r7 s> 0x37d2 goto +0;" 6: r0 = 0;" 7: exit;" Perf profiling shows that most of the time is spent in mark_chain_precision() ~95%. The easiest way to explain why this program causes problems is to apply the following patch: diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 0c216e71cec7..4b4823961abe 100644 \--- a/include/linux/bpf.h \+++ b/include/linux/bpf.h \@@ -1926,7 +1926,7 @@ struct bpf_array { }; }; -#define BPF_COMPLEXITY_LIMIT_INSNS 1000000 /* yes. 1M insns */ +#define BPF_COMPLEXITY_LIMIT_INSNS 256 /* yes. 1M insns */ #define MAX_TAIL_CALL_CNT 33 /* Maximum number of loops for bpf_loop and bpf_iter_num. diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f514247ba8ba..75e88be3bb3e 100644 \--- a/kernel/bpf/verifier.c \+++ b/kernel/bpf/verifier.c \@@ -18024,8 +18024,13 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) skip_inf_loop_check: if (!force_new_state && env->jmps_processed - env->prev_jmps_processed < 20 && - env->insn_processed - env->prev_insn_processed < 100) + env->insn_processed - env->prev_insn_processed < 100) { + verbose(env, "is_state_visited: suppressing checkpoint at %d, %d jmps processed, cur->jmp_history_cnt is %d\n", + env->insn_idx, + env->jmps_processed - env->prev_jmps_processed, + cur->jmp_history_cnt); add_new_state = false; + } goto miss; } /* If sl->state is a part of a loop and this loop's entry is a part of \@@ -18142,6 +18147,9 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) if (!add_new_state) return 0; + verbose(env, "is_state_visited: new checkpoint at %d, resetting env->jmps_processed\n", + env->insn_idx); + /* There were no equivalent states, remember the current one. * Technically the current state is not proven to be safe yet, * but it will either reach outer most bpf_exit (which means it's safe) And observe verification log: ... is_state_visited: new checkpoint at 5, resetting env->jmps_processed 5: R1=ctx() R7=ctx(...) 5: (65) if r7 s> 0x37d2 goto pc+0 ; R7=ctx(...) 6: (b7) r0 = 0 ; R0_w=0 7: (95) exit from 5 to 6: R1=ctx() R7=ctx(...) R10=fp0 6: R1=ctx() R7=ctx(...) R10=fp0 6: (b7) r0 = 0 ; R0_w=0 7: (95) exit is_state_visited: suppressing checkpoint at 1, 3 jmps processed, cur->jmp_history_cnt is 74 from 2 to 1: R1=ctx() R7_w=scalar(...) R10=fp0 1: R1=ctx() R7_w=scalar(...) R10=fp0 1: (07) r7 += 447767737 is_state_visited: suppressing checkpoint at 2, 3 jmps processed, cur->jmp_history_cnt is 75 2: R7_w=scalar(...) 2: (45) if r7 & 0x702000 goto pc-2 ... mark_precise 152 steps for r7 ... 2: R7_w=scalar(...) is_state_visited: suppressing checkpoint at 1, 4 jmps processed, cur->jmp_history_cnt is 75 1: (07) r7 += 447767737 is_state_visited: suppressing checkpoint at 2, 4 jmps processed, cur->jmp_history_cnt is 76 2: R7_w=scalar(...) 2: (45) if r7 & 0x702000 goto pc-2 ... BPF program is too large. Processed 257 insn The log output shows that checkpoint at label (1) is never created, because it is suppressed by `skip_inf_loop_check` logic: a. When 'if' at (2) is processed it pushes a state with insn_idx (1) onto stack and proceeds to (3); b. At (5) checkpoint is created, and this resets env->{jmps,insns}_processed. c. Verification proceeds and reaches `exit`; d. State saved at step (a) is popped from stack and is_state_visited() considers if checkpoint needs to be added, but because env->{jmps,insns}_processed had been just reset at step (b) the `skip_inf_loop_check` logic forces `add_new_state` to false. e. Verifier proceeds with current state, which slowly accumulates more and more entries in the jump history. The accumulation of entries in the jump history is a problem because of two factors: - it eventually exhausts memory available for kmalloc() allocation; - mark_chain_precision() traverses the jump history of a state, meaning that if `r7` is marked precise, verifier would iterate ever growing jump history until parent state boundary is reached. (note: the log also shows a REG INVARIANTS VIOLATION warning upon jset processing, but that's another bug to fix). With this patch applied, the example above is rejected by verifier under 1s of time, reaching 1M instructions limit. The program is a simplified reproducer from syzbot report. Previous discussion could be found at [1]. The patch does not cause any changes in verification performance, when tested on selftests from veristat.cfg and cilium programs taken from [2]. [1] https://lore.kernel.org/bpf/20241009021254.2805446-1-eddyz87@gmail.com/ [2] https://github.com/anakryiko/cilium Changelog: - v1 -> v2: - moved patch to bpf tree; - moved force_new_state variable initialization after declaration and shortened the comment. v1: https://lore.kernel.org/bpf/20241018020307.1766906-1-eddyz87@gmail.com/ Fixes: 2589726d12a1 ("bpf: introduce bounded loops") Reported-by: syzbot+7e46cdef14bf496a3ab4@syzkaller.appspotmail.com Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20241029172641.1042523-1-eddyz87@gmail.com Closes: https://lore.kernel.org/bpf/670429f6.050a0220.49194.0517.GAE@google.com/
2024-10-29sched: Pass correct scheduling policy to __setscheduler_classAboorva Devarajan
Commit 98442f0ccd82 ("sched: Fix delayed_dequeue vs switched_from_fair()") overlooked that __setscheduler_prio(), now __setscheduler_class() relies on p->policy for task_should_scx(), and moved the call before __setscheduler_params() updates it, causing it to be using the old p->policy value. Resolve this by changing task_should_scx() to take the policy itself instead of a task pointer, such that __sched_setscheduler() can pass in the updated policy. Fixes: 98442f0ccd82 ("sched: Fix delayed_dequeue vs switched_from_fair()") Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Tejun Heo <tj@kernel.org>
2024-10-28resource,kexec: walk_system_ram_res_rev must retain resource flagsGregory Price
walk_system_ram_res_rev() erroneously discards resource flags when passing the information to the callback. This causes systems with IORESOURCE_SYSRAM_DRIVER_MANAGED memory to have these resources selected during kexec to store kexec buffers if that memory happens to be at placed above normal system ram. This leads to undefined behavior after reboot. If the kexec buffer is never touched, nothing happens. If the kexec buffer is touched, it could lead to a crash (like below) or undefined behavior. Tested on a system with CXL memory expanders with driver managed memory, TPM enabled, and CONFIG_IMA_KEXEC=y. Adding printk's showed the flags were being discarded and as a result the check for IORESOURCE_SYSRAM_DRIVER_MANAGED passes. find_next_iomem_res: name(System RAM (kmem)) start(10000000000) end(1034fffffff) flags(83000200) locate_mem_hole_top_down: start(10000000000) end(1034fffffff) flags(0) [.] BUG: unable to handle page fault for address: ffff89834ffff000 [.] #PF: supervisor read access in kernel mode [.] #PF: error_code(0x0000) - not-present page [.] PGD c04c8bf067 P4D c04c8bf067 PUD c04c8be067 PMD 0 [.] Oops: 0000 [#1] SMP [.] RIP: 0010:ima_restore_measurement_list+0x95/0x4b0 [.] RSP: 0018:ffffc900000d3a80 EFLAGS: 00010286 [.] RAX: 0000000000001000 RBX: 0000000000000000 RCX: ffff89834ffff000 [.] RDX: 0000000000000018 RSI: ffff89834ffff000 RDI: ffff89834ffff018 [.] RBP: ffffc900000d3ba0 R08: 0000000000000020 R09: ffff888132b8a900 [.] R10: 4000000000000000 R11: 000000003a616d69 R12: 0000000000000000 [.] R13: ffffffff8404ac28 R14: 0000000000000000 R15: ffff89834ffff000 [.] FS: 0000000000000000(0000) GS:ffff893d44640000(0000) knlGS:0000000000000000 [.] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [.] ata5: SATA link down (SStatus 0 SControl 300) [.] CR2: ffff89834ffff000 CR3: 000001034d00f001 CR4: 0000000000770ef0 [.] PKRU: 55555554 [.] Call Trace: [.] <TASK> [.] ? __die+0x78/0xc0 [.] ? page_fault_oops+0x2a8/0x3a0 [.] ? exc_page_fault+0x84/0x130 [.] ? asm_exc_page_fault+0x22/0x30 [.] ? ima_restore_measurement_list+0x95/0x4b0 [.] ? template_desc_init_fields+0x317/0x410 [.] ? crypto_alloc_tfm_node+0x9c/0xc0 [.] ? init_ima_lsm+0x30/0x30 [.] ima_load_kexec_buffer+0x72/0xa0 [.] ima_init+0x44/0xa0 [.] __initstub__kmod_ima__373_1201_init_ima7+0x1e/0xb0 [.] ? init_ima_lsm+0x30/0x30 [.] do_one_initcall+0xad/0x200 [.] ? idr_alloc_cyclic+0xaa/0x110 [.] ? new_slab+0x12c/0x420 [.] ? new_slab+0x12c/0x420 [.] ? number+0x12a/0x430 [.] ? sysvec_apic_timer_interrupt+0xa/0x80 [.] ? asm_sysvec_apic_timer_interrupt+0x16/0x20 [.] ? parse_args+0xd4/0x380 [.] ? parse_args+0x14b/0x380 [.] kernel_init_freeable+0x1c1/0x2b0 [.] ? rest_init+0xb0/0xb0 [.] kernel_init+0x16/0x1a0 [.] ret_from_fork+0x2f/0x40 [.] ? rest_init+0xb0/0xb0 [.] ret_from_fork_asm+0x11/0x20 [.] </TASK> Link: https://lore.kernel.org/all/20231114091658.228030-1-bhe@redhat.com/ Link: https://lkml.kernel.org/r/20241017190347.5578-1-gourry@gourry.net Fixes: 7acf164b259d ("resource: add walk_system_ram_res_rev()") Signed-off-by: Gregory Price <gourry@gourry.net> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Cc: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-28fork: only invoke khugepaged, ksm hooks if no errorLorenzo Stoakes
There is no reason to invoke these hooks early against an mm that is in an incomplete state. The change in commit d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") makes this more pertinent as we may be in a state where entries in the maple tree are not yet consistent. Their placement early in dup_mmap() only appears to have been meaningful for early error checking, and since functionally it'd require a very small allocation to fail (in practice 'too small to fail') that'd only occur in the most dire circumstances, meaning the fork would fail or be OOM'd in any case. Since both khugepaged and KSM tracking are there to provide optimisations to memory performance rather than critical functionality, it doesn't really matter all that much if, under such dire memory pressure, we fail to register an mm with these. As a result, we follow the example of commit d2081b2bf819 ("mm: khugepaged: make khugepaged_enter() void function") and make ksm_fork() a void function also. We only expose the mm to these functions once we are done with them and only if no error occurred in the fork operation. Link: https://lkml.kernel.org/r/e0cb8b840c9d1d5a6e84d4f8eff5f3f2022aa10c.1729014377.git.lorenzo.stoakes@oracle.com Fixes: d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reported-by: Jann Horn <jannh@google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Jann Horn <jannh@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Linus Torvalds <torvalds@linuxfoundation.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-28fork: do not invoke uffd on fork if error occursLorenzo Stoakes
Patch series "fork: do not expose incomplete mm on fork". During fork we may place the virtual memory address space into an inconsistent state before the fork operation is complete. In addition, we may encounter an error during the fork operation that indicates that the virtual memory address space is invalidated. As a result, we should not be exposing it in any way to external machinery that might interact with the mm or VMAs, machinery that is not designed to deal with incomplete state. We specifically update the fork logic to defer khugepaged and ksm to the end of the operation and only to be invoked if no error arose, and disallow uffd from observing fork events should an error have occurred. This patch (of 2): Currently on fork we expose the virtual address space of a process to userland unconditionally if uffd is registered in VMAs, regardless of whether an error arose in the fork. This is performed in dup_userfaultfd_complete() which is invoked unconditionally, and performs two duties - invoking registered handlers for the UFFD_EVENT_FORK event via dup_fctx(), and clearing down userfaultfd_fork_ctx objects established in dup_userfaultfd(). This is problematic, because the virtual address space may not yet be correctly initialised if an error arose. The change in commit d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") makes this more pertinent as we may be in a state where entries in the maple tree are not yet consistent. We address this by, on fork error, ensuring that we roll back state that we would otherwise expect to clean up through the event being handled by userland and perform the memory freeing duty otherwise performed by dup_userfaultfd_complete(). We do this by implementing a new function, dup_userfaultfd_fail(), which performs the same loop, only decrementing reference counts. Note that we perform mmgrab() on the parent and child mm's, however userfaultfd_ctx_put() will mmdrop() this once the reference count drops to zero, so we will avoid memory leaks correctly here. Link: https://lkml.kernel.org/r/cover.1729014377.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/d3691d58bb58712b6fb3df2be441d175bd3cdf07.1729014377.git.lorenzo.stoakes@oracle.com Fixes: d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reported-by: Jann Horn <jannh@google.com> Reviewed-by: Jann Horn <jannh@google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Linus Torvalds <torvalds@linuxfoundation.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-27Merge tag 'ftrace-v6.12-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull ftrace fixes from Steven Rostedt: - Fix missing mutex unlock in error path of register_ftrace_graph() A previous fix added a return on an error path and forgot to unlock the mutex. Instead of dealing with error paths, use guard(mutex) as the mutex is just released at the exit of the function anyway. Other functions in this file should be updated with this, but that's a cleanup and not a fix. - Change cpuhp setup name to be consistent with other cpuhp states The same fix that the above patch fixes added a cpuhp_setup_state() call with the name of "fgraph_idle_init". I was informed that it should instead be something like: "fgraph:online". Update that too. * tag 'ftrace-v6.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: fgraph: Change the name of cpuhp state to "fgraph:online" fgraph: Fix missing unlock in register_ftrace_graph()
2024-10-27genirq/msi: Fix off-by-one error in msi_domain_alloc()Jinjie Ruan
The error path in msi_domain_alloc(), frees the already allocated MSI interrupts in a loop, but the loop condition terminates when the index reaches zero, which fails to free the first allocated MSI interrupt at index zero. Check for >= 0 so that msi[0] is freed as well. Fixes: f3cf8bb0d6c3 ("genirq: Add generic msi irq domain support") Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20241026063639.10711-1-ruanjinjie@huawei.com
2024-10-27posix-cpu-timers: Clear TICK_DEP_BIT_POSIX_TIMER on cloneBenjamin Segall
When cloning a new thread, its posix_cputimers are not inherited, and are cleared by posix_cputimers_init(). However, this does not clear the tick dependency it creates in tsk->tick_dep_mask, and the handler does not reach the code to clear the dependency if there were no timers to begin with. Thus if a thread has a cputimer running before clone/fork, all descendants will prevent nohz_full unless they create a cputimer of their own. Fix this by entirely clearing the tick_dep_mask in copy_process(). (There is currently no inherited state that needs a tick dependency) Process-wide timers do not have this problem because fork does not copy signal_struct as a baseline, it creates one from scratch. Fixes: b78783000d5c ("posix-cpu-timers: Migrate to use new tick dependency mask model") Signed-off-by: Ben Segall <bsegall@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/xm26o737bq8o.fsf@google.com
2024-10-26sched/numa: Fix the potential null pointer dereference in task_numa_work()Shawn Wang
When running stress-ng-vm-segv test, we found a null pointer dereference error in task_numa_work(). Here is the backtrace: [323676.066985] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 ...... [323676.067108] CPU: 35 PID: 2694524 Comm: stress-ng-vm-se ...... [323676.067113] pstate: 23401009 (nzCv daif +PAN -UAO +TCO +DIT +SSBS BTYPE=--) [323676.067115] pc : vma_migratable+0x1c/0xd0 [323676.067122] lr : task_numa_work+0x1ec/0x4e0 [323676.067127] sp : ffff8000ada73d20 [323676.067128] x29: ffff8000ada73d20 x28: 0000000000000000 x27: 000000003e89f010 [323676.067130] x26: 0000000000080000 x25: ffff800081b5c0d8 x24: ffff800081b27000 [323676.067133] x23: 0000000000010000 x22: 0000000104d18cc0 x21: ffff0009f7158000 [323676.067135] x20: 0000000000000000 x19: 0000000000000000 x18: ffff8000ada73db8 [323676.067138] x17: 0001400000000000 x16: ffff800080df40b0 x15: 0000000000000035 [323676.067140] x14: ffff8000ada73cc8 x13: 1fffe0017cc72001 x12: ffff8000ada73cc8 [323676.067142] x11: ffff80008001160c x10: ffff000be639000c x9 : ffff8000800f4ba4 [323676.067145] x8 : ffff000810375000 x7 : ffff8000ada73974 x6 : 0000000000000001 [323676.067147] x5 : 0068000b33e26707 x4 : 0000000000000001 x3 : ffff0009f7158000 [323676.067149] x2 : 0000000000000041 x1 : 0000000000004400 x0 : 0000000000000000 [323676.067152] Call trace: [323676.067153] vma_migratable+0x1c/0xd0 [323676.067155] task_numa_work+0x1ec/0x4e0 [323676.067157] task_work_run+0x78/0xd8 [323676.067161] do_notify_resume+0x1ec/0x290 [323676.067163] el0_svc+0x150/0x160 [323676.067167] el0t_64_sync_handler+0xf8/0x128 [323676.067170] el0t_64_sync+0x17c/0x180 [323676.067173] Code: d2888001 910003fd f9000bf3 aa0003f3 (f9401000) [323676.067177] SMP: stopping secondary CPUs [323676.070184] Starting crashdump kernel... stress-ng-vm-segv in stress-ng is used to stress test the SIGSEGV error handling function of the system, which tries to cause a SIGSEGV error on return from unmapping the whole address space of the child process. Normally this program will not cause kernel crashes. But before the munmap system call returns to user mode, a potential task_numa_work() for numa balancing could be added and executed. In this scenario, since the child process has no vma after munmap, the vma_next() in task_numa_work() will return a null pointer even if the vma iterator restarts from 0. Recheck the vma pointer before dereferencing it in task_numa_work(). Fixes: 214dbc428137 ("sched: convert to vma iterator") Signed-off-by: Shawn Wang <shawnwang@linux.alibaba.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org # v6.2+ Link: https://lkml.kernel.org/r/20241025022208.125527-1-shawnwang@linux.alibaba.com
2024-10-25scx: Fix raciness in scx_ops_bypass()David Vernet
scx_ops_bypass() can currently race on the ops enable / disable path as follows: 1. scx_ops_bypass(true) called on enable path, bypass depth is set to 1 2. An op on the init path exits, which schedules scx_ops_disable_workfn() 3. scx_ops_bypass(false) is called on the disable path, and bypass depth is decremented to 0 4. kthread is scheduled to execute scx_ops_disable_workfn() 5. scx_ops_bypass(true) called, bypass depth set to 1 6. scx_ops_bypass() races when iterating over CPUs While it's not safe to take any blocking locks on the bypass path, it is safe to take a raw spinlock which cannot be preempted. This patch therefore updates scx_ops_bypass() to use a raw spinlock to synchronize, and changes scx_ops_bypass_depth to be a regular int. Without this change, we observe the following warnings when running the 'exit' sched_ext selftest (sometimes requires a couple of runs): .[root@virtme-ng sched_ext]# ./runner -t exit ===== START ===== TEST: exit ... [ 14.935078] WARNING: CPU: 2 PID: 360 at kernel/sched/ext.c:4332 scx_ops_bypass+0x1ca/0x280 [ 14.935126] Modules linked in: [ 14.935150] CPU: 2 UID: 0 PID: 360 Comm: sched_ext_ops_h Not tainted 6.11.0-virtme #24 [ 14.935192] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 [ 14.935242] Sched_ext: exit (enabling+all) [ 14.935244] RIP: 0010:scx_ops_bypass+0x1ca/0x280 [ 14.935300] Code: ff ff ff e8 48 96 10 00 fb e9 08 ff ff ff c6 05 7b 34 e8 01 01 90 48 c7 c7 89 86 88 87 e8 be 1d f8 ff 90 0f 0b 90 90 eb 95 90 <0f> 0b 90 41 8b 84 24 24 0a 00 00 eb 97 90 0f 0b 90 41 8b 84 24 24 [ 14.935394] RSP: 0018:ffffb706c0957ce0 EFLAGS: 00010002 [ 14.935424] RAX: 0000000000000009 RBX: 0000000000000001 RCX: 00000000e3fb8b2a [ 14.935465] RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff88a4c080 [ 14.935512] RBP: 0000000000009b56 R08: 0000000000000004 R09: 00000003f12e520a [ 14.935555] R10: ffffffff863a9795 R11: 0000000000000000 R12: ffff8fc5fec31300 [ 14.935598] R13: ffff8fc5fec31318 R14: 0000000000000286 R15: 0000000000000018 [ 14.935642] FS: 0000000000000000(0000) GS:ffff8fc5fe680000(0000) knlGS:0000000000000000 [ 14.935684] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 14.935721] CR2: 0000557d92890b88 CR3: 000000002464a000 CR4: 0000000000750ef0 [ 14.935765] PKRU: 55555554 [ 14.935782] Call Trace: [ 14.935802] <TASK> [ 14.935823] ? __warn+0xce/0x220 [ 14.935850] ? scx_ops_bypass+0x1ca/0x280 [ 14.935881] ? report_bug+0xc1/0x160 [ 14.935909] ? handle_bug+0x61/0x90 [ 14.935934] ? exc_invalid_op+0x1a/0x50 [ 14.935959] ? asm_exc_invalid_op+0x1a/0x20 [ 14.935984] ? raw_spin_rq_lock_nested+0x15/0x30 [ 14.936019] ? scx_ops_bypass+0x1ca/0x280 [ 14.936046] ? srso_alias_return_thunk+0x5/0xfbef5 [ 14.936081] ? __pfx_scx_ops_disable_workfn+0x10/0x10 [ 14.936111] scx_ops_disable_workfn+0x146/0xac0 [ 14.936142] ? finish_task_switch+0xa9/0x2c0 [ 14.936172] ? srso_alias_return_thunk+0x5/0xfbef5 [ 14.936211] ? __pfx_scx_ops_disable_workfn+0x10/0x10 [ 14.936244] kthread_worker_fn+0x101/0x2c0 [ 14.936268] ? __pfx_kthread_worker_fn+0x10/0x10 [ 14.936299] kthread+0xec/0x110 [ 14.936327] ? __pfx_kthread+0x10/0x10 [ 14.936351] ret_from_fork+0x37/0x50 [ 14.936374] ? __pfx_kthread+0x10/0x10 [ 14.936400] ret_from_fork_asm+0x1a/0x30 [ 14.936427] </TASK> [ 14.936443] irq event stamp: 21002 [ 14.936467] hardirqs last enabled at (21001): [<ffffffff863aa35f>] resched_cpu+0x9f/0xd0 [ 14.936521] hardirqs last disabled at (21002): [<ffffffff863dd0ba>] scx_ops_bypass+0x11a/0x280 [ 14.936571] softirqs last enabled at (20642): [<ffffffff863683d7>] __irq_exit_rcu+0x67/0xd0 [ 14.936622] softirqs last disabled at (20637): [<ffffffff863683d7>] __irq_exit_rcu+0x67/0xd0 [ 14.936672] ---[ end trace 0000000000000000 ]--- [ 14.953282] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF) [ 14.953352] ------------[ cut here ]------------ [ 14.953383] WARNING: CPU: 2 PID: 360 at kernel/sched/ext.c:4335 scx_ops_bypass+0x1d8/0x280 [ 14.953428] Modules linked in: [ 14.953453] CPU: 2 UID: 0 PID: 360 Comm: sched_ext_ops_h Tainted: G W 6.11.0-virtme #24 [ 14.953505] Tainted: [W]=WARN [ 14.953527] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 [ 14.953574] RIP: 0010:scx_ops_bypass+0x1d8/0x280 [ 14.953603] Code: c6 05 7b 34 e8 01 01 90 48 c7 c7 89 86 88 87 e8 be 1d f8 ff 90 0f 0b 90 90 eb 95 90 0f 0b 90 41 8b 84 24 24 0a 00 00 eb 97 90 <0f> 0b 90 41 8b 84 24 24 0a 00 00 eb 92 f3 0f 1e fa 49 8d 84 24 f0 [ 14.953693] RSP: 0018:ffffb706c0957ce0 EFLAGS: 00010046 [ 14.953722] RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000001 [ 14.953763] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8fc5fec31318 [ 14.953804] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 [ 14.953845] R10: ffffffff863a9795 R11: 0000000000000000 R12: ffff8fc5fec31300 [ 14.953888] R13: ffff8fc5fec31318 R14: 0000000000000286 R15: 0000000000000018 [ 14.953934] FS: 0000000000000000(0000) GS:ffff8fc5fe680000(0000) knlGS:0000000000000000 [ 14.953974] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 14.954009] CR2: 0000557d92890b88 CR3: 000000002464a000 CR4: 0000000000750ef0 [ 14.954052] PKRU: 55555554 [ 14.954068] Call Trace: [ 14.954085] <TASK> [ 14.954102] ? __warn+0xce/0x220 [ 14.954126] ? scx_ops_bypass+0x1d8/0x280 [ 14.954150] ? report_bug+0xc1/0x160 [ 14.954178] ? handle_bug+0x61/0x90 [ 14.954203] ? exc_invalid_op+0x1a/0x50 [ 14.954226] ? asm_exc_invalid_op+0x1a/0x20 [ 14.954250] ? raw_spin_rq_lock_nested+0x15/0x30 [ 14.954285] ? scx_ops_bypass+0x1d8/0x280 [ 14.954311] ? __mutex_unlock_slowpath+0x3a/0x260 [ 14.954343] scx_ops_disable_workfn+0xa3e/0xac0 [ 14.954381] ? __pfx_scx_ops_disable_workfn+0x10/0x10 [ 14.954413] kthread_worker_fn+0x101/0x2c0 [ 14.954442] ? __pfx_kthread_worker_fn+0x10/0x10 [ 14.954479] kthread+0xec/0x110 [ 14.954507] ? __pfx_kthread+0x10/0x10 [ 14.954530] ret_from_fork+0x37/0x50 [ 14.954553] ? __pfx_kthread+0x10/0x10 [ 14.954576] ret_from_fork_asm+0x1a/0x30 [ 14.954603] </TASK> [ 14.954621] irq event stamp: 21002 [ 14.954644] hardirqs last enabled at (21001): [<ffffffff863aa35f>] resched_cpu+0x9f/0xd0 [ 14.954686] hardirqs last disabled at (21002): [<ffffffff863dd0ba>] scx_ops_bypass+0x11a/0x280 [ 14.954735] softirqs last enabled at (20642): [<ffffffff863683d7>] __irq_exit_rcu+0x67/0xd0 [ 14.954782] softirqs last disabled at (20637): [<ffffffff863683d7>] __irq_exit_rcu+0x67/0xd0 [ 14.954829] ---[ end trace 0000000000000000 ]--- [ 15.022283] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF) [ 15.092282] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF) [ 15.149282] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF) ok 1 exit # ===== END ===== And with it, the test passes without issue after 1000s of runs: .[root@virtme-ng sched_ext]# ./runner -t exit ===== START ===== TEST: exit DESCRIPTION: Verify we can cleanly exit a scheduler in multiple places OUTPUT: [ 7.412856] sched_ext: BPF scheduler "exit" enabled [ 7.427924] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF) [ 7.466677] sched_ext: BPF scheduler "exit" enabled [ 7.475923] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF) [ 7.512803] sched_ext: BPF scheduler "exit" enabled [ 7.532924] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF) [ 7.586809] sched_ext: BPF scheduler "exit" enabled [ 7.595926] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF) [ 7.661923] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF) [ 7.723923] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF) ok 1 exit # ===== END ===== ============================= RESULTS: PASSED: 1 SKIPPED: 0 FAILED: 0 Fixes: f0e1a0643a59 ("sched_ext: Implement BPF extensible scheduler class") Signed-off-by: David Vernet <void@manifault.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-10-24fgraph: Change the name of cpuhp state to "fgraph:online"Steven Rostedt
The cpuhp state name given to cpuhp_setup_state() is "fgraph_idle_init" which doesn't really conform to the names that are used for cpu hotplug setups. Instead rename it to "fgraph:online" to be in line with other states. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/20241024222944.473d88c5@rorschach.local.home Suggested-by: Masami Hiramatsu <mhiramat@kernel.org> Fixes: 2c02f7375e658 ("fgraph: Use CPU hotplug mechanism to initialize idle shadow stacks") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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