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2022-04-08watch_queue: Actually free the watchDavid Howells
[ Upstream commit 3d8dcf278b1ee1eff1e90be848fa2237db4c07a7 ] free_watch() does everything barring actually freeing the watch object. Fix this by adding the missing kfree. kmemleak produces a report something like the following. Note that as an address can be seen in the first word, the watch would appear to have gone through call_rcu(). BUG: memory leak unreferenced object 0xffff88810ce4a200 (size 96): comm "syz-executor352", pid 3605, jiffies 4294947473 (age 13.720s) hex dump (first 32 bytes): e0 82 48 0d 81 88 ff ff 00 00 00 00 00 00 00 00 ..H............. 80 a2 e4 0c 81 88 ff ff 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff8214e6cc>] kmalloc include/linux/slab.h:581 [inline] [<ffffffff8214e6cc>] kzalloc include/linux/slab.h:714 [inline] [<ffffffff8214e6cc>] keyctl_watch_key+0xec/0x2e0 security/keys/keyctl.c:1800 [<ffffffff8214ec84>] __do_sys_keyctl+0x3c4/0x490 security/keys/keyctl.c:2016 [<ffffffff84493a25>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff84493a25>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [<ffffffff84600068>] entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reported-and-tested-by: syzbot+6e2de48f06cdb2884bfc@syzkaller.appspotmail.com Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-08watch_queue: Fix NULL dereference in error cleanupDavid Howells
[ Upstream commit a635415a064e77bcfbf43da413fd9dfe0bbed9cb ] In watch_queue_set_size(), the error cleanup code doesn't take account of the fact that __free_page() can't handle a NULL pointer when trying to free up buffer pages that did get allocated. Fix this by only calling __free_page() on the pages actually allocated. Without the fix, this can lead to something like the following: BUG: KASAN: null-ptr-deref in __free_pages+0x1f/0x1b0 mm/page_alloc.c:5473 Read of size 4 at addr 0000000000000034 by task syz-executor168/3599 ... Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 __kasan_report mm/kasan/report.c:446 [inline] kasan_report.cold+0x66/0xdf mm/kasan/report.c:459 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189 instrument_atomic_read include/linux/instrumented.h:71 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline] page_ref_count include/linux/page_ref.h:67 [inline] put_page_testzero include/linux/mm.h:717 [inline] __free_pages+0x1f/0x1b0 mm/page_alloc.c:5473 watch_queue_set_size+0x499/0x630 kernel/watch_queue.c:275 pipe_ioctl+0xac/0x2b0 fs/pipe.c:632 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reported-and-tested-by: syzbot+d55757faa9b80590767b@syzkaller.appspotmail.com Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-08PM: suspend: fix return value of __setup handlerRandy Dunlap
[ Upstream commit 7a64ca17e4dd50d5f910769167f3553902777844 ] If an invalid option is given for "test_suspend=<option>", the entire string is added to init's environment, so return 1 instead of 0 from the __setup handler. Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc5 test_suspend=invalid" and Run /sbin/init as init process with arguments: /sbin/init with environment: HOME=/ TERM=linux BOOT_IMAGE=/boot/bzImage-517rc5 test_suspend=invalid Fixes: 2ce986892faf ("PM / sleep: Enhance test_suspend option with repeat capability") Fixes: 27ddcc6596e5 ("PM / sleep: Add state field to pm_states[] entries") Fixes: a9d7052363a6 ("PM: Separate suspend to RAM functionality from core") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru> Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-08PM: hibernate: fix __setup handler error handlingRandy Dunlap
[ Upstream commit ba7ffcd4c4da374b0f64666354eeeda7d3827131 ] If an invalid value is used in "resumedelay=<seconds>", it is silently ignored. Add a warning message and then let the __setup handler return 1 to indicate that the kernel command line option has been handled. Fixes: 317cf7e5e85e3 ("PM / hibernate: convert simple_strtoul to kstrtoul") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru> Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-08audit: log AUDIT_TIME_* records only from rulesRichard Guy Briggs
[ Upstream commit 272ceeaea355214b301530e262a0df8600bfca95 ] AUDIT_TIME_* events are generated when there are syscall rules present that are not related to time keeping. This will produce noisy log entries that could flood the logs and hide events we really care about. Rather than immediately produce the AUDIT_TIME_* records, store the data in the context and log it at syscall exit time respecting the filter rules. Note: This eats the audit_buffer, unlike any others in show_special(). Please see https://bugzilla.redhat.com/show_bug.cgi?id=1991919 Fixes: 7e8eda734d30 ("ntp: Audit NTP parameters adjustment") Fixes: 2d87a0674bd6 ("timekeeping: Audit clock adjustments") Signed-off-by: Richard Guy Briggs <rgb@redhat.com> [PM: fixed style/whitespace issues] Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-08ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZEJann Horn
commit ee1fee900537b5d9560e9f937402de5ddc8412f3 upstream. Setting PTRACE_O_SUSPEND_SECCOMP is supposed to be a highly privileged operation because it allows the tracee to completely bypass all seccomp filters on kernels with CONFIG_CHECKPOINT_RESTORE=y. It is only supposed to be settable by a process with global CAP_SYS_ADMIN, and only if that process is not subject to any seccomp filters at all. However, while these permission checks were done on the PTRACE_SETOPTIONS path, they were missing on the PTRACE_SEIZE path, which also sets user-specified ptrace flags. Move the permissions checks out into a helper function and let both ptrace_attach() and ptrace_setoptions() call it. Cc: stable@kernel.org Fixes: 13c4a90119d2 ("seccomp: add ptrace options for suspend/resume") Signed-off-by: Jann Horn <jannh@google.com> Link: https://lkml.kernel.org/r/20220319010838.1386861-1-jannh@google.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-08locking/lockdep: Avoid potential access of invalid memory in lock_classWaiman Long
commit 61cc4534b6550997c97a03759ab46b29d44c0017 upstream. It was found that reading /proc/lockdep after a lockdep splat may potentially cause an access to freed memory if lockdep_unregister_key() is called after the splat but before access to /proc/lockdep [1]. This is due to the fact that graph_lock() call in lockdep_unregister_key() fails after the clearing of debug_locks by the splat process. After lockdep_unregister_key() is called, the lock_name may be freed but the corresponding lock_class structure still have a reference to it. That invalid memory pointer will then be accessed when /proc/lockdep is read by a user and a use-after-free (UAF) error will be reported if KASAN is enabled. To fix this problem, lockdep_unregister_key() is now modified to always search for a matching key irrespective of the debug_locks state and zap the corresponding lock class if a matching one is found. [1] https://lore.kernel.org/lkml/77f05c15-81b6-bddd-9650-80d5f23fe330@i-love.sakura.ne.jp/ Fixes: 8b39adbee805 ("locking/lockdep: Make lockdep_unregister_key() honor 'debug_locks' again") Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Cc: Cheng-Jui Wang <cheng-jui.wang@mediatek.com> Link: https://lkml.kernel.org/r/20220103023558.1377055-1-longman@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-08swiotlb: fix info leak with DMA_FROM_DEVICEHalil Pasic
commit ddbd89deb7d32b1fbb879f48d68fda1a8ac58e8e upstream. The problem I'm addressing was discovered by the LTP test covering cve-2018-1000204. A short description of what happens follows: 1) The test case issues a command code 00 (TEST UNIT READY) via the SG_IO interface with: dxfer_len == 524288, dxdfer_dir == SG_DXFER_FROM_DEV and a corresponding dxferp. The peculiar thing about this is that TUR is not reading from the device. 2) In sg_start_req() the invocation of blk_rq_map_user() effectively bounces the user-space buffer. As if the device was to transfer into it. Since commit a45b599ad808 ("scsi: sg: allocate with __GFP_ZERO in sg_build_indirect()") we make sure this first bounce buffer is allocated with GFP_ZERO. 3) For the rest of the story we keep ignoring that we have a TUR, so the device won't touch the buffer we prepare as if the we had a DMA_FROM_DEVICE type of situation. My setup uses a virtio-scsi device and the buffer allocated by SG is mapped by the function virtqueue_add_split() which uses DMA_FROM_DEVICE for the "in" sgs (here scatter-gather and not scsi generics). This mapping involves bouncing via the swiotlb (we need swiotlb to do virtio in protected guest like s390 Secure Execution, or AMD SEV). 4) When the SCSI TUR is done, we first copy back the content of the second (that is swiotlb) bounce buffer (which most likely contains some previous IO data), to the first bounce buffer, which contains all zeros. Then we copy back the content of the first bounce buffer to the user-space buffer. 5) The test case detects that the buffer, which it zero-initialized, ain't all zeros and fails. One can argue that this is an swiotlb problem, because without swiotlb we leak all zeros, and the swiotlb should be transparent in a sense that it does not affect the outcome (if all other participants are well behaved). Copying the content of the original buffer into the swiotlb buffer is the only way I can think of to make swiotlb transparent in such scenarios. So let's do just that if in doubt, but allow the driver to tell us that the whole mapped buffer is going to be overwritten, in which case we can preserve the old behavior and avoid the performance impact of the extra bounce. Signed-off-by: Halil Pasic <pasic@linux.ibm.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-28rcu: Don't deboost before reporting expedited quiescent statePaul E. McKenney
commit 10c535787436d62ea28156a4b91365fd89b5a432 upstream. Currently rcu_preempt_deferred_qs_irqrestore() releases rnp->boost_mtx before reporting the expedited quiescent state. Under heavy real-time load, this can result in this function being preempted before the quiescent state is reported, which can in turn prevent the expedited grace period from completing. Tim Murray reports that the resulting expedited grace periods can take hundreds of milliseconds and even more than one second, when they should normally complete in less than a millisecond. This was fine given that there were no particular response-time constraints for synchronize_rcu_expedited(), as it was designed for throughput rather than latency. However, some users now need sub-100-millisecond response-time constratints. This patch therefore follows Neeraj's suggestion (seconded by Tim and by Uladzislau Rezki) of simply reversing the two operations. Reported-by: Tim Murray <timmurray@google.com> Reported-by: Joel Fernandes <joelaf@google.com> Reported-by: Neeraj Upadhyay <quic_neeraju@quicinc.com> Reviewed-by: Neeraj Upadhyay <quic_neeraju@quicinc.com> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Tested-by: Tim Murray <timmurray@google.com> Cc: Todd Kjos <tkjos@google.com> Cc: Sandeep Patil <sspatil@google.com> Cc: <stable@vger.kernel.org> # 5.4.x Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-28cgroup-v1: Correct privileges check in release_agent writesMichal Koutný
commit 467a726b754f474936980da793b4ff2ec3e382a7 upstream. The idea is to check: a) the owning user_ns of cgroup_ns, b) capabilities in init_user_ns. The commit 24f600856418 ("cgroup-v1: Require capabilities to set release_agent") got this wrong in the write handler of release_agent since it checked user_ns of the opener (may be different from the owning user_ns of cgroup_ns). Secondly, to avoid possibly confused deputy, the capability of the opener must be checked. Fixes: 24f600856418 ("cgroup-v1: Require capabilities to set release_agent") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/stable/20220216121142.GB30035@blackbody.suse.cz/ Signed-off-by: Michal Koutný <mkoutny@suse.com> Reviewed-by: Masami Ichikawa(CIP) <masami.ichikawa@cybertrust.co.jp> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-28cgroup: Use open-time cgroup namespace for process migration perm checksTejun Heo
commit e57457641613fef0d147ede8bd6a3047df588b95 upstream. cgroup process migration permission checks are performed at write time as whether a given operation is allowed or not is dependent on the content of the write - the PID. This currently uses current's cgroup namespace which is a potential security weakness as it may allow scenarios where a less privileged process tricks a more privileged one into writing into a fd that it created. This patch makes cgroup remember the cgroup namespace at the time of open and uses it for migration permission checks instad of current's. Note that this only applies to cgroup2 as cgroup1 doesn't have namespace support. This also fixes a use-after-free bug on cgroupns reported in https://lore.kernel.org/r/00000000000048c15c05d0083397@google.com Note that backporting this fix also requires the preceding patch. Reported-by: "Eric W. Biederman" <ebiederm@xmission.com> Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Reported-by: syzbot+50f5cf33a284ce738b62@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/00000000000048c15c05d0083397@google.com Fixes: 5136f6365ce3 ("cgroup: implement "nsdelegate" mount option") Signed-off-by: Tejun Heo <tj@kernel.org> [mkoutny: v5.10: duplicate ns check in procs/threads write handler, adjust context] Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-28cgroup: Allocate cgroup_file_ctx for kernfs_open_file->privTejun Heo
commit 0d2b5955b36250a9428c832664f2079cbf723bec upstream. of->priv is currently used by each interface file implementation to store private information. This patch collects the current two private data usages into struct cgroup_file_ctx which is allocated and freed by the common path. This allows generic private data which applies to multiple files, which will be used to in the following patch. Note that cgroup_procs iterator is now embedded as procs.iter in the new cgroup_file_ctx so that it doesn't need to be allocated and freed separately. v2: union dropped from cgroup_file_ctx and the procs iterator is embedded in cgroup_file_ctx as suggested by Linus. v3: Michal pointed out that cgroup1's procs pidlist uses of->priv too. Converted. Didn't change to embedded allocation as cgroup1 pidlists get stored for caching. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Michal Koutný <mkoutny@suse.com> [mkoutny: v5.10: modify cgroup.pressure handlers, adjust context] Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-16watch_queue: Fix filter limit checkDavid Howells
commit c993ee0f9f81caf5767a50d1faeba39a0dc82af2 upstream. In watch_queue_set_filter(), there are a couple of places where we check that the filter type value does not exceed what the type_filter bitmap can hold. One place calculates the number of bits by: if (tf[i].type >= sizeof(wfilter->type_filter) * 8) which is fine, but the second does: if (tf[i].type >= sizeof(wfilter->type_filter) * BITS_PER_LONG) which is not. This can lead to a couple of out-of-bounds writes due to a too-large type: (1) __set_bit() on wfilter->type_filter (2) Writing more elements in wfilter->filters[] than we allocated. Fix this by just using the proper WATCH_TYPE__NR instead, which is the number of types we actually know about. The bug may cause an oops looking something like: BUG: KASAN: slab-out-of-bounds in watch_queue_set_filter+0x659/0x740 Write of size 4 at addr ffff88800d2c66bc by task watch_queue_oob/611 ... Call Trace: <TASK> dump_stack_lvl+0x45/0x59 print_address_description.constprop.0+0x1f/0x150 ... kasan_report.cold+0x7f/0x11b ... watch_queue_set_filter+0x659/0x740 ... __x64_sys_ioctl+0x127/0x190 do_syscall_64+0x43/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae Allocated by task 611: kasan_save_stack+0x1e/0x40 __kasan_kmalloc+0x81/0xa0 watch_queue_set_filter+0x23a/0x740 __x64_sys_ioctl+0x127/0x190 do_syscall_64+0x43/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff88800d2c66a0 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 28 bytes inside of 32-byte region [ffff88800d2c66a0, ffff88800d2c66c0) Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-16watch_queue: Make comment about setting ->defunct more accurateDavid Howells
commit 4edc0760412b0c4ecefc7e02cb855b310b122825 upstream. watch_queue_clear() has a comment stating that setting ->defunct to true preventing new additions as well as preventing notifications. Whilst the latter is true, the first bit is superfluous since at the time this function is called, the pipe cannot be accessed to add new event sources. Remove the "new additions" bit from the comment. Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-16watch_queue: Fix lack of barrier/sync/lock between post and readDavid Howells
commit 2ed147f015af2b48f41c6f0b6746aa9ea85c19f3 upstream. There's nothing to synchronise post_one_notification() versus pipe_read(). Whilst posting is done under pipe->rd_wait.lock, the reader only takes pipe->mutex which cannot bar notification posting as that may need to be made from contexts that cannot sleep. Fix this by setting pipe->head with a barrier in post_one_notification() and reading pipe->head with a barrier in pipe_read(). If that's not sufficient, the rd_wait.lock will need to be taken, possibly in a ->confirm() op so that it only applies to notifications. The lock would, however, have to be dropped before copy_page_to_iter() is invoked. Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-16watch_queue: Free the alloc bitmap when the watch_queue is torn downDavid Howells
commit 7ea1a0124b6da246b5bc8c66cddaafd36acf3ecb upstream. Free the watch_queue note allocation bitmap when the watch_queue is destroyed. Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-16watch_queue: Fix the alloc bitmap size to reflect notes allocatedDavid Howells
commit 3b4c0371928c17af03e8397ac842346624017ce6 upstream. Currently, watch_queue_set_size() sets the number of notes available in wqueue->nr_notes according to the number of notes allocated, but sets the size of the bitmap to the unrounded number of notes originally asked for. Fix this by setting the bitmap size to the number of notes we're actually going to make available (ie. the number allocated). Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-16watch_queue: Fix to always request a pow-of-2 pipe ring sizeDavid Howells
commit 96a4d8912b28451cd62825fd7caa0e66e091d938 upstream. The pipe ring size must always be a power of 2 as the head and tail pointers are masked off by AND'ing with the size of the ring - 1. watch_queue_set_size(), however, lets you specify any number of notes between 1 and 511. This number is passed through to pipe_resize_ring() without checking/forcing its alignment. Fix this by rounding the number of slots required up to the nearest power of two. The request is meant to guarantee that at least that many notifications can be generated before the queue is full, so rounding down isn't an option, but, alternatively, it may be better to give an error if we aren't allowed to allocate that much ring space. Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-16watch_queue: Fix to release page in ->release()David Howells
commit c1853fbadcba1497f4907971e7107888e0714c81 upstream. When a pipe ring descriptor points to a notification message, the refcount on the backing page is incremented by the generic get function, but the release function, which marks the bitmap, doesn't drop the page ref. Fix this by calling generic_pipe_buf_release() at the end of watch_queue_pipe_buf_release(). Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-16tracing: Ensure trace buffer is at least 4096 bytes largeSven Schnelle
[ Upstream commit 7acf3a127bb7c65ff39099afd78960e77b2ca5de ] Booting the kernel with 'trace_buf_size=1' give a warning at boot during the ftrace selftests: [ 0.892809] Running postponed tracer tests: [ 0.892893] Testing tracer function: [ 0.901899] Callback from call_rcu_tasks_trace() invoked. [ 0.983829] Callback from call_rcu_tasks_rude() invoked. [ 1.072003] .. bad ring buffer .. corrupted trace buffer .. [ 1.091944] Callback from call_rcu_tasks() invoked. [ 1.097695] PASSED [ 1.097701] Testing dynamic ftrace: .. filter failed count=0 ..FAILED! [ 1.353474] ------------[ cut here ]------------ [ 1.353478] WARNING: CPU: 0 PID: 1 at kernel/trace/trace.c:1951 run_tracer_selftest+0x13c/0x1b0 Therefore enforce a minimum of 4096 bytes to make the selftest pass. Link: https://lkml.kernel.org/r/20220214134456.1751749-1-svens@linux.ibm.com Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-03-11x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation ↵Josh Poimboeuf
reporting commit 44a3918c8245ab10c6c9719dd12e7a8d291980d8 upstream. With unprivileged eBPF enabled, eIBRS (without retpoline) is vulnerable to Spectre v2 BHB-based attacks. When both are enabled, print a warning message and report it in the 'spectre_v2' sysfs vulnerabilities file. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> [fllinden@amazon.com: backported to 5.10] Signed-off-by: Frank van der Linden <fllinden@amazon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-08tracing: Fix return value of __setup handlersRandy Dunlap
commit 1d02b444b8d1345ea4708db3bab4db89a7784b55 upstream. __setup() handlers should generally return 1 to indicate that the boot options have been handled. Using invalid option values causes the entire kernel boot option string to be reported as Unknown and added to init's environment strings, polluting it. Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc6 kprobe_event=p,syscall_any,$arg1 trace_options=quiet trace_clock=jiffies", will be passed to user space. Run /sbin/init as init process with arguments: /sbin/init with environment: HOME=/ TERM=linux BOOT_IMAGE=/boot/bzImage-517rc6 kprobe_event=p,syscall_any,$arg1 trace_options=quiet trace_clock=jiffies Return 1 from the __setup() handlers so that init's environment is not polluted with kernel boot options. Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Link: https://lkml.kernel.org/r/20220303031744.32356-1-rdunlap@infradead.org Cc: stable@vger.kernel.org Fixes: 7bcfaf54f591 ("tracing: Add trace_options kernel command line parameter") Fixes: e1e232ca6b8f ("tracing: Add trace_clock=<clock> kernel parameter") Fixes: 970988e19eb0 ("tracing/kprobe: Add kprobe_event= boot parameter") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-08tracing/histogram: Fix sorting on old "cpu" valueSteven Rostedt (Google)
commit 1d1898f65616c4601208963c3376c1d828cbf2c7 upstream. When trying to add a histogram against an event with the "cpu" field, it was impossible due to "cpu" being a keyword to key off of the running CPU. So to fix this, it was changed to "common_cpu" to match the other generic fields (like "common_pid"). But since some scripts used "cpu" for keying off of the CPU (for events that did not have "cpu" as a field, which is most of them), a backward compatibility trick was added such that if "cpu" was used as a key, and the event did not have "cpu" as a field name, then it would fallback and switch over to "common_cpu". This fix has a couple of subtle bugs. One was that when switching over to "common_cpu", it did not change the field name, it just set a flag. But the code still found a "cpu" field. The "cpu" field is used for filtering and is returned when the event does not have a "cpu" field. This was found by: # cd /sys/kernel/tracing # echo hist:key=cpu,pid:sort=cpu > events/sched/sched_wakeup/trigger # cat events/sched/sched_wakeup/hist Which showed the histogram unsorted: { cpu: 19, pid: 1175 } hitcount: 1 { cpu: 6, pid: 239 } hitcount: 2 { cpu: 23, pid: 1186 } hitcount: 14 { cpu: 12, pid: 249 } hitcount: 2 { cpu: 3, pid: 994 } hitcount: 5 Instead of hard coding the "cpu" checks, take advantage of the fact that trace_event_field_field() returns a special field for "cpu" and "CPU" if the event does not have "cpu" as a field. This special field has the "filter_type" of "FILTER_CPU". Check that to test if the returned field is of the CPU type instead of doing the string compare. Also, fix the sorting bug by testing for the hist_field flag of HIST_FIELD_FL_CPU when setting up the sort routine. Otherwise it will use the special CPU field to know what compare routine to use, and since that special field does not have a size, it returns tracing_map_cmp_none. Cc: stable@vger.kernel.org Fixes: 1e3bac71c505 ("tracing/histogram: Rename "cpu" to "common_cpu"") Reported-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-08sched/topology: Fix sched_domain_topology_level alloc in sched_init_numa()Dietmar Eggemann
commit 71e5f6644fb2f3304fcb310145ded234a37e7cc1 upstream. Commit "sched/topology: Make sched_init_numa() use a set for the deduplicating sort" allocates 'i + nr_levels (level)' instead of 'i + nr_levels + 1' sched_domain_topology_level. This led to an Oops (on Arm64 juno with CONFIG_SCHED_DEBUG): sched_init_domains build_sched_domains() __free_domain_allocs() __sdt_free() { ... for_each_sd_topology(tl) ... sd = *per_cpu_ptr(sdd->sd, j); <-- ... } Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Vincent Guittot <vincent.guittot@linaro.org> Tested-by: Barry Song <song.bao.hua@hisilicon.com> Link: https://lkml.kernel.org/r/6000e39e-7d28-c360-9cd6-8798fd22a9bf@arm.com Signed-off-by: dann frazier <dann.frazier@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-08sched/topology: Make sched_init_numa() use a set for the deduplicating sortValentin Schneider
commit 620a6dc40754dc218f5b6389b5d335e9a107fd29 upstream. The deduplicating sort in sched_init_numa() assumes that the first line in the distance table contains all unique values in the entire table. I've been trying to pen what this exactly means for the topology, but it's not straightforward. For instance, topology.c uses this example: node 0 1 2 3 0: 10 20 20 30 1: 20 10 20 20 2: 20 20 10 20 3: 30 20 20 10 0 ----- 1 | / | | / | | / | 2 ----- 3 Which works out just fine. However, if we swap nodes 0 and 1: 1 ----- 0 | / | | / | | / | 2 ----- 3 we get this distance table: node 0 1 2 3 0: 10 20 20 20 1: 20 10 20 30 2: 20 20 10 20 3: 20 30 20 10 Which breaks the deduplicating sort (non-representative first line). In this case this would just be a renumbering exercise, but it so happens that we can have a deduplicating sort that goes through the whole table in O(n²) at the extra cost of a temporary memory allocation (i.e. any form of set). The ACPI spec (SLIT) mentions distances are encoded on 8 bits. Following this, implement the set as a 256-bits bitmap. Should this not be satisfactory (i.e. we want to support 32-bit values), then we'll have to go for some other sparse set implementation. This has the added benefit of letting us allocate just the right amount of memory for sched_domains_numa_distance[], rather than an arbitrary (nr_node_ids + 1). Note: DT binding equivalent (distance-map) decodes distances as 32-bit values. Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210122123943.1217-2-valentin.schneider@arm.com Signed-off-by: dann frazier <dann.frazier@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-08rcu/nocb: Fix missed nocb_timer requeueFrederic Weisbecker
commit b2fcf2102049f6e56981e0ab3d9b633b8e2741da upstream. This sequence of events can lead to a failure to requeue a CPU's ->nocb_timer: 1. There are no callbacks queued for any CPU covered by CPU 0-2's ->nocb_gp_kthread. Note that ->nocb_gp_kthread is associated with CPU 0. 2. CPU 1 enqueues its first callback with interrupts disabled, and thus must defer awakening its ->nocb_gp_kthread. It therefore queues its rcu_data structure's ->nocb_timer. At this point, CPU 1's rdp->nocb_defer_wakeup is RCU_NOCB_WAKE. 3. CPU 2, which shares the same ->nocb_gp_kthread, also enqueues a callback, but with interrupts enabled, allowing it to directly awaken the ->nocb_gp_kthread. 4. The newly awakened ->nocb_gp_kthread associates both CPU 1's and CPU 2's callbacks with a future grace period and arranges for that grace period to be started. 5. This ->nocb_gp_kthread goes to sleep waiting for the end of this future grace period. 6. This grace period elapses before the CPU 1's timer fires. This is normally improbably given that the timer is set for only one jiffy, but timers can be delayed. Besides, it is possible that kernel was built with CONFIG_RCU_STRICT_GRACE_PERIOD=y. 7. The grace period ends, so rcu_gp_kthread awakens the ->nocb_gp_kthread, which in turn awakens both CPU 1's and CPU 2's ->nocb_cb_kthread. Then ->nocb_gb_kthread sleeps waiting for more newly queued callbacks. 8. CPU 1's ->nocb_cb_kthread invokes its callback, then sleeps waiting for more invocable callbacks. 9. Note that neither kthread updated any ->nocb_timer state, so CPU 1's ->nocb_defer_wakeup is still set to RCU_NOCB_WAKE. 10. CPU 1 enqueues its second callback, this time with interrupts enabled so it can wake directly ->nocb_gp_kthread. It does so with calling wake_nocb_gp() which also cancels the pending timer that got queued in step 2. But that doesn't reset CPU 1's ->nocb_defer_wakeup which is still set to RCU_NOCB_WAKE. So CPU 1's ->nocb_defer_wakeup and its ->nocb_timer are now desynchronized. 11. ->nocb_gp_kthread associates the callback queued in 10 with a new grace period, arranges for that grace period to start and sleeps waiting for it to complete. 12. The grace period ends, rcu_gp_kthread awakens ->nocb_gp_kthread, which in turn wakes up CPU 1's ->nocb_cb_kthread which then invokes the callback queued in 10. 13. CPU 1 enqueues its third callback, this time with interrupts disabled so it must queue a timer for a deferred wakeup. However the value of its ->nocb_defer_wakeup is RCU_NOCB_WAKE which incorrectly indicates that a timer is already queued. Instead, CPU 1's ->nocb_timer was cancelled in 10. CPU 1 therefore fails to queue the ->nocb_timer. 14. CPU 1 has its pending callback and it may go unnoticed until some other CPU ever wakes up ->nocb_gp_kthread or CPU 1 ever calls an explicit deferred wakeup, for example, during idle entry. This commit fixes this bug by resetting rdp->nocb_defer_wakeup everytime we delete the ->nocb_timer. It is quite possible that there is a similar scenario involving ->nocb_bypass_timer and ->nocb_defer_wakeup. However, despite some effort from several people, a failure scenario has not yet been located. However, that by no means guarantees that no such scenario exists. Finding a failure scenario is left as an exercise for the reader, and the "Fixes:" tag below relates to ->nocb_bypass_timer instead of ->nocb_timer. Fixes: d1b222c6be1f (rcu/nocb: Add bypass callback queueing) Cc: <stable@vger.kernel.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Neeraj Upadhyay <neeraju@codeaurora.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-08tracing: Add ustring operation to filtering string pointersSteven Rostedt
[ Upstream commit f37c3bbc635994eda203a6da4ba0f9d05165a8d6 ] Since referencing user space pointers is special, if the user wants to filter on a field that is a pointer to user space, then they need to specify it. Add a ".ustring" attribute to the field name for filters to state that the field is pointing to user space such that the kernel can take the appropriate action to read that pointer. Link: https://lore.kernel.org/all/yt9d8rvmt2jq.fsf@linux.ibm.com/ Fixes: 77360f9bbc7e ("tracing: Add test for user space strings when filtering on string pointers") Tested-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-03-08tracing: Add test for user space strings when filtering on string pointersSteven Rostedt
[ Upstream commit 77360f9bbc7e5e2ab7a2c8b4c0244fbbfcfc6f62 ] Pingfan reported that the following causes a fault: echo "filename ~ \"cpu\"" > events/syscalls/sys_enter_openat/filter echo 1 > events/syscalls/sys_enter_at/enable The reason is that trace event filter treats the user space pointer defined by "filename" as a normal pointer to compare against the "cpu" string. The following bug happened: kvm-03-guest16 login: [72198.026181] BUG: unable to handle page fault for address: 00007fffaae8ef60 #PF: supervisor read access in kernel mode #PF: error_code(0x0001) - permissions violation PGD 80000001008b7067 P4D 80000001008b7067 PUD 2393f1067 PMD 2393ec067 PTE 8000000108f47867 Oops: 0001 [#1] PREEMPT SMP PTI CPU: 1 PID: 1 Comm: systemd Kdump: loaded Not tainted 5.14.0-32.el9.x86_64 #1 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 RIP: 0010:strlen+0x0/0x20 Code: 48 89 f9 74 09 48 83 c1 01 80 39 00 75 f7 31 d2 44 0f b6 04 16 44 88 04 11 48 83 c2 01 45 84 c0 75 ee c3 0f 1f 80 00 00 00 00 <80> 3f 00 74 10 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 c3 31 RSP: 0018:ffffb5b900013e48 EFLAGS: 00010246 RAX: 0000000000000018 RBX: ffff8fc1c49ede00 RCX: 0000000000000000 RDX: 0000000000000020 RSI: ffff8fc1c02d601c RDI: 00007fffaae8ef60 RBP: 00007fffaae8ef60 R08: 0005034f4ddb8ea4 R09: 0000000000000000 R10: ffff8fc1c02d601c R11: 0000000000000000 R12: ffff8fc1c8a6e380 R13: 0000000000000000 R14: ffff8fc1c02d6010 R15: ffff8fc1c00453c0 FS: 00007fa86123db40(0000) GS:ffff8fc2ffd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fffaae8ef60 CR3: 0000000102880001 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: filter_pred_pchar+0x18/0x40 filter_match_preds+0x31/0x70 ftrace_syscall_enter+0x27a/0x2c0 syscall_trace_enter.constprop.0+0x1aa/0x1d0 do_syscall_64+0x16/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fa861d88664 The above happened because the kernel tried to access user space directly and triggered a "supervisor read access in kernel mode" fault. Worse yet, the memory could not even be loaded yet, and a SEGFAULT could happen as well. This could be true for kernel space accessing as well. To be even more robust, test both kernel and user space strings. If the string fails to read, then simply have the filter fail. Note, TASK_SIZE is used to determine if the pointer is user or kernel space and the appropriate strncpy_from_kernel/user_nofault() function is used to copy the memory. For some architectures, the compare to TASK_SIZE may always pick user space or kernel space. If it gets it wrong, the only thing is that the filter will fail to match. In the future, this needs to be fixed to have the event denote which should be used. But failing a filter is much better than panicing the machine, and that can be solved later. Link: https://lore.kernel.org/all/20220107044951.22080-1-kernelfans@gmail.com/ Link: https://lkml.kernel.org/r/20220110115532.536088fd@gandalf.local.home Cc: stable@vger.kernel.org Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Reported-by: Pingfan Liu <kernelfans@gmail.com> Tested-by: Pingfan Liu <kernelfans@gmail.com> Fixes: 87a342f5db69d ("tracing/filters: Support filtering for char * strings") Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-03-02tracing: Have traceon and traceoff trigger honor the instanceSteven Rostedt (Google)
commit 302e9edd54985f584cfc180098f3554774126969 upstream. If a trigger is set on an event to disable or enable tracing within an instance, then tracing should be disabled or enabled in the instance and not at the top level, which is confusing to users. Link: https://lkml.kernel.org/r/20220223223837.14f94ec3@rorschach.local.home Cc: stable@vger.kernel.org Fixes: ae63b31e4d0e2 ("tracing: Separate out trace events from global variables") Tested-by: Daniel Bristot de Oliveira <bristot@kernel.org> Reviewed-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-02bpf: Add schedule points in batch opsEric Dumazet
commit 75134f16e7dd0007aa474b281935c5f42e79f2c8 upstream. syzbot reported various soft lockups caused by bpf batch operations. INFO: task kworker/1:1:27 blocked for more than 140 seconds. INFO: task hung in rcu_barrier Nothing prevents batch ops to process huge amount of data, we need to add schedule points in them. Note that maybe_wait_bpf_programs(map) calls from generic_map_delete_batch() can be factorized by moving the call after the loop. This will be done later in -next tree once we get this fix merged, unless there is strong opinion doing this optimization sooner. Fixes: aa2e93b8e58e ("bpf: Add generic support for update and delete batch ops") Fixes: cb4d03ab499d ("bpf: Add generic support for lookup batch op") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Stanislav Fomichev <sdf@google.com> Acked-by: Brian Vazquez <brianvv@google.com> Link: https://lore.kernel.org/bpf/20220217181902.808742-1-eric.dumazet@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-02cgroup/cpuset: Fix a race between cpuset_attach() and cpu hotplugZhang Qiao
commit 05c7b7a92cc87ff8d7fde189d0fade250697573c upstream. As previously discussed(https://lkml.org/lkml/2022/1/20/51), cpuset_attach() is affected with similar cpu hotplug race, as follow scenario: cpuset_attach() cpu hotplug --------------------------- ---------------------- down_write(cpuset_rwsem) guarantee_online_cpus() // (load cpus_attach) sched_cpu_deactivate set_cpu_active() // will change cpu_active_mask set_cpus_allowed_ptr(cpus_attach) __set_cpus_allowed_ptr_locked() // (if the intersection of cpus_attach and cpu_active_mask is empty, will return -EINVAL) up_write(cpuset_rwsem) To avoid races such as described above, protect cpuset_attach() call with cpu_hotplug_lock. Fixes: be367d099270 ("cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time") Cc: stable@vger.kernel.org # v2.6.32+ Reported-by: Zhao Gongyi <zhaogongyi@huawei.com> Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-23lockdep: Correct lock_classes index mappingCheng Jui Wang
commit 28df029d53a2fd80c1b8674d47895648ad26dcfb upstream. A kernel exception was hit when trying to dump /proc/lockdep_chains after lockdep report "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!": Unable to handle kernel paging request at virtual address 00054005450e05c3 ... 00054005450e05c3] address between user and kernel address ranges ... pc : [0xffffffece769b3a8] string+0x50/0x10c lr : [0xffffffece769ac88] vsnprintf+0x468/0x69c ... Call trace: string+0x50/0x10c vsnprintf+0x468/0x69c seq_printf+0x8c/0xd8 print_name+0x64/0xf4 lc_show+0xb8/0x128 seq_read_iter+0x3cc/0x5fc proc_reg_read_iter+0xdc/0x1d4 The cause of the problem is the function lock_chain_get_class() will shift lock_classes index by 1, but the index don't need to be shifted anymore since commit 01bb6f0af992 ("locking/lockdep: Change the range of class_idx in held_lock struct") already change the index to start from 0. The lock_classes[-1] located at chain_hlocks array. When printing lock_classes[-1] after the chain_hlocks entries are modified, the exception happened. The output of lockdep_chains are incorrect due to this problem too. Fixes: f611e8cf98ec ("lockdep: Take read/write status in consideration when generate chainkey") Signed-off-by: Cheng Jui Wang <cheng-jui.wang@mediatek.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20220210105011.21712-1-cheng-jui.wang@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-23copy_process(): Move fd_install() out of sighand->siglock critical sectionWaiman Long
commit ddc204b517e60ae64db34f9832dc41dafa77c751 upstream. I was made aware of the following lockdep splat: [ 2516.308763] ===================================================== [ 2516.309085] WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected [ 2516.309433] 5.14.0-51.el9.aarch64+debug #1 Not tainted [ 2516.309703] ----------------------------------------------------- [ 2516.310149] stress-ng/153663 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: [ 2516.310512] ffff0000e422b198 (&newf->file_lock){+.+.}-{2:2}, at: fd_install+0x368/0x4f0 [ 2516.310944] and this task is already holding: [ 2516.311248] ffff0000c08140d8 (&sighand->siglock){-.-.}-{2:2}, at: copy_process+0x1e2c/0x3e80 [ 2516.311804] which would create a new lock dependency: [ 2516.312066] (&sighand->siglock){-.-.}-{2:2} -> (&newf->file_lock){+.+.}-{2:2} [ 2516.312446] but this new dependency connects a HARDIRQ-irq-safe lock: [ 2516.312983] (&sighand->siglock){-.-.}-{2:2} : [ 2516.330700] Possible interrupt unsafe locking scenario: [ 2516.331075] CPU0 CPU1 [ 2516.331328] ---- ---- [ 2516.331580] lock(&newf->file_lock); [ 2516.331790] local_irq_disable(); [ 2516.332231] lock(&sighand->siglock); [ 2516.332579] lock(&newf->file_lock); [ 2516.332922] <Interrupt> [ 2516.333069] lock(&sighand->siglock); [ 2516.333291] *** DEADLOCK *** [ 2516.389845] stack backtrace: [ 2516.390101] CPU: 3 PID: 153663 Comm: stress-ng Kdump: loaded Not tainted 5.14.0-51.el9.aarch64+debug #1 [ 2516.390756] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 2516.391155] Call trace: [ 2516.391302] dump_backtrace+0x0/0x3e0 [ 2516.391518] show_stack+0x24/0x30 [ 2516.391717] dump_stack_lvl+0x9c/0xd8 [ 2516.391938] dump_stack+0x1c/0x38 [ 2516.392247] print_bad_irq_dependency+0x620/0x710 [ 2516.392525] check_irq_usage+0x4fc/0x86c [ 2516.392756] check_prev_add+0x180/0x1d90 [ 2516.392988] validate_chain+0x8e0/0xee0 [ 2516.393215] __lock_acquire+0x97c/0x1e40 [ 2516.393449] lock_acquire.part.0+0x240/0x570 [ 2516.393814] lock_acquire+0x90/0xb4 [ 2516.394021] _raw_spin_lock+0xe8/0x154 [ 2516.394244] fd_install+0x368/0x4f0 [ 2516.394451] copy_process+0x1f5c/0x3e80 [ 2516.394678] kernel_clone+0x134/0x660 [ 2516.394895] __do_sys_clone3+0x130/0x1f4 [ 2516.395128] __arm64_sys_clone3+0x5c/0x7c [ 2516.395478] invoke_syscall.constprop.0+0x78/0x1f0 [ 2516.395762] el0_svc_common.constprop.0+0x22c/0x2c4 [ 2516.396050] do_el0_svc+0xb0/0x10c [ 2516.396252] el0_svc+0x24/0x34 [ 2516.396436] el0t_64_sync_handler+0xa4/0x12c [ 2516.396688] el0t_64_sync+0x198/0x19c [ 2517.491197] NET: Registered PF_ATMPVC protocol family [ 2517.491524] NET: Registered PF_ATMSVC protocol family [ 2591.991877] sched: RT throttling activated One way to solve this problem is to move the fd_install() call out of the sighand->siglock critical section. Before commit 6fd2fe494b17 ("copy_process(): don't use ksys_close() on cleanups"), the pidfd installation was done without holding both the task_list lock and the sighand->siglock. Obviously, holding these two locks are not really needed to protect the fd_install() call. So move the fd_install() call down to after the releases of both locks. Link: https://lore.kernel.org/r/20220208163912.1084752-1-longman@redhat.com Fixes: 6fd2fe494b17 ("copy_process(): don't use ksys_close() on cleanups") Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-23tracing: Fix tp_printk option related with tp_printk_stop_on_bootJaeSang Yoo
[ Upstream commit 3203ce39ac0b2a57a84382ec184c7d4a0bede175 ] The kernel parameter "tp_printk_stop_on_boot" starts with "tp_printk" which is the same as another kernel parameter "tp_printk". If "tp_printk" setup is called before the "tp_printk_stop_on_boot", it will override the latter and keep it from being set. This is similar to other kernel parameter issues, such as: Commit 745a600cf1a6 ("um: console: Ignore console= option") or init/do_mounts.c:45 (setup function of "ro" kernel param) Fix it by checking for a "_" right after the "tp_printk" and if that exists do not process the parameter. Link: https://lkml.kernel.org/r/20220208195421.969326-1-jsyoo5b@gmail.com Signed-off-by: JaeSang Yoo <jsyoo5b@gmail.com> [ Fixed up change log and added space after if condition ] Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-02-23gcc-plugins/stackleak: Use noinstr in favor of notraceKees Cook
[ Upstream commit dcb85f85fa6f142aae1fe86f399d4503d49f2b60 ] While the stackleak plugin was already using notrace, objtool is now a bit more picky. Update the notrace uses to noinstr. Silences the following objtool warnings when building with: CONFIG_DEBUG_ENTRY=y CONFIG_STACK_VALIDATION=y CONFIG_VMLINUX_VALIDATION=y CONFIG_GCC_PLUGIN_STACKLEAK=y vmlinux.o: warning: objtool: do_syscall_64()+0x9: call to stackleak_track_stack() leaves .noinstr.text section vmlinux.o: warning: objtool: do_int80_syscall_32()+0x9: call to stackleak_track_stack() leaves .noinstr.text section vmlinux.o: warning: objtool: exc_general_protection()+0x22: call to stackleak_track_stack() leaves .noinstr.text section vmlinux.o: warning: objtool: fixup_bad_iret()+0x20: call to stackleak_track_stack() leaves .noinstr.text section vmlinux.o: warning: objtool: do_machine_check()+0x27: call to stackleak_track_stack() leaves .noinstr.text section vmlinux.o: warning: objtool: .text+0x5346e: call to stackleak_erase() leaves .noinstr.text section vmlinux.o: warning: objtool: .entry.text+0x143: call to stackleak_erase() leaves .noinstr.text section vmlinux.o: warning: objtool: .entry.text+0x10eb: call to stackleak_erase() leaves .noinstr.text section vmlinux.o: warning: objtool: .entry.text+0x17f9: call to stackleak_erase() leaves .noinstr.text section Note that the plugin's addition of calls to stackleak_track_stack() from noinstr functions is expected to be safe, as it isn't runtime instrumentation and is self-contained. Cc: Alexander Popov <alex.popov@linux.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-02-23Revert "module, async: async_synchronize_full() on module init iff async is ↵Igor Pylypiv
used" [ Upstream commit 67d6212afda218d564890d1674bab28e8612170f ] This reverts commit 774a1221e862b343388347bac9b318767336b20b. We need to finish all async code before the module init sequence is done. In the reverted commit the PF_USED_ASYNC flag was added to mark a thread that called async_schedule(). Then the PF_USED_ASYNC flag was used to determine whether or not async_synchronize_full() needs to be invoked. This works when modprobe thread is calling async_schedule(), but it does not work if module dispatches init code to a worker thread which then calls async_schedule(). For example, PCI driver probing is invoked from a worker thread based on a node where device is attached: if (cpu < nr_cpu_ids) error = work_on_cpu(cpu, local_pci_probe, &ddi); else error = local_pci_probe(&ddi); We end up in a situation where a worker thread gets the PF_USED_ASYNC flag set instead of the modprobe thread. As a result, async_synchronize_full() is not invoked and modprobe completes without waiting for the async code to finish. The issue was discovered while loading the pm80xx driver: (scsi_mod.scan=async) modprobe pm80xx worker ... do_init_module() ... pci_call_probe() work_on_cpu(local_pci_probe) local_pci_probe() pm8001_pci_probe() scsi_scan_host() async_schedule() worker->flags |= PF_USED_ASYNC; ... < return from worker > ... if (current->flags & PF_USED_ASYNC) <--- false async_synchronize_full(); Commit 21c3c5d28007 ("block: don't request module during elevator init") fixed the deadlock issue which the reverted commit 774a1221e862 ("module, async: async_synchronize_full() on module init iff async is used") tried to fix. Since commit 0fdff3ec6d87 ("async, kmod: warn on synchronous request_module() from async workers") synchronous module loading from async is not allowed. Given that the original deadlock issue is fixed and it is no longer allowed to call synchronous request_module() from async we can remove PF_USED_ASYNC flag to make module init consistently invoke async_synchronize_full() unless async module probe is requested. Signed-off-by: Igor Pylypiv <ipylypiv@google.com> Reviewed-by: Changyuan Lyu <changyuanl@google.com> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-02-23rcu: Do not report strict GPs for outgoing CPUsPaul E. McKenney
commit bfb3aa735f82c8d98b32a669934ee7d6b346264d upstream. An outgoing CPU is marked offline in a stop-machine handler and most of that CPU's services stop at that point, including IRQ work queues. However, that CPU must take another pass through the scheduler and through a number of CPU-hotplug notifiers, many of which contain RCU readers. In the past, these readers were not a problem because the outgoing CPU has interrupts disabled, so that rcu_read_unlock_special() would not be invoked, and thus RCU would never attempt to queue IRQ work on the outgoing CPU. This changed with the advent of the CONFIG_RCU_STRICT_GRACE_PERIOD Kconfig option, in which rcu_read_unlock_special() is invoked upon exit from almost all RCU read-side critical sections. Worse yet, because interrupts are disabled, rcu_read_unlock_special() cannot immediately report a quiescent state and will therefore attempt to defer this reporting, for example, by queueing IRQ work. Which fails with a splat because the CPU is already marked as being offline. But it turns out that there is no need to report this quiescent state because rcu_report_dead() will do this job shortly after the outgoing CPU makes its final dive into the idle loop. This commit therefore makes rcu_read_unlock_special() refrain from queuing IRQ work onto outgoing CPUs. Fixes: 44bad5b3cca2 ("rcu: Do full report for .need_qs for strict GPs") Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Jann Horn <jannh@google.com> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-16perf: Fix list corruption in perf_cgroup_switch()Song Liu
commit 5f4e5ce638e6a490b976ade4a40017b40abb2da0 upstream. There's list corruption on cgrp_cpuctx_list. This happens on the following path: perf_cgroup_switch: list_for_each_entry(cgrp_cpuctx_list) cpu_ctx_sched_in ctx_sched_in ctx_pinned_sched_in merge_sched_in perf_cgroup_event_disable: remove the event from the list Use list_for_each_entry_safe() to allow removing an entry during iteration. Fixes: 058fe1c0440e ("perf/core: Make cgroup switch visit only cpuctxs with cgroup events") Signed-off-by: Song Liu <song@kernel.org> Reviewed-by: Rik van Riel <riel@surriel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220204004057.2961252-1-song@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-16PM: s2idle: ACPI: Fix wakeup interrupts handlingRafael J. Wysocki
commit cb1f65c1e1424a4b5e4a86da8aa3b8fd8459c8ec upstream. After commit e3728b50cd9b ("ACPI: PM: s2idle: Avoid possible race related to the EC GPE") wakeup interrupts occurring immediately after the one discarded by acpi_s2idle_wake() may be missed. Moreover, if the SCI triggers again immediately after the rearming in acpi_s2idle_wake(), that wakeup may be missed too. The problem is that pm_system_irq_wakeup() only calls pm_system_wakeup() when pm_wakeup_irq is 0, but that's not the case any more after the interrupt causing acpi_s2idle_wake() to run until pm_wakeup_irq is cleared by the pm_wakeup_clear() call in s2idle_loop(). However, there may be wakeup interrupts occurring in that time frame and if that happens, they will be missed. To address that issue first move the clearing of pm_wakeup_irq to the point at which it is known that the interrupt causing acpi_s2idle_wake() to tun will be discarded, before rearming the SCI for wakeup. Moreover, because that only reduces the size of the time window in which the issue may manifest itself, allow pm_system_irq_wakeup() to register two second wakeup interrupts in a row and, when discarding the first one, replace it with the second one. [Of course, this assumes that only one wakeup interrupt can be discarded in one go, but currently that is the case and I am not aware of any plans to change that.] Fixes: e3728b50cd9b ("ACPI: PM: s2idle: Avoid possible race related to the EC GPE") Cc: 5.4+ <stable@vger.kernel.org> # 5.4+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-16perf: Always wake the parent eventJames Clark
[ Upstream commit 961c39121759ad09a89598ec4ccdd34ae0468a19 ] When using per-process mode and event inheritance is set to true, forked processes will create a new perf events via inherit_event() -> perf_event_alloc(). But these events will not have ring buffers assigned to them. Any call to wakeup will be dropped if it's called on an event with no ring buffer assigned because that's the object that holds the wakeup list. If the child event is disabled due to a call to perf_aux_output_begin() or perf_aux_output_end(), the wakeup is dropped leaving userspace hanging forever on the poll. Normally the event is explicitly re-enabled by userspace after it wakes up to read the aux data, but in this case it does not get woken up so the event remains disabled. This can be reproduced when using Arm SPE and 'stress' which forks once before running the workload. By looking at the list of aux buffers read, it's apparent that they stop after the fork: perf record -e arm_spe// -vvv -- stress -c 1 With this patch applied they continue to be printed. This behaviour doesn't happen when using systemwide or per-cpu mode. Reported-by: Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com> Signed-off-by: James Clark <james.clark@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20211206113840.130802-2-james.clark@arm.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-02-16PM: hibernate: Remove register_nosave_region_late()Amadeusz Sławiński
[ Upstream commit 33569ef3c754a82010f266b7b938a66a3ccf90a4 ] It is an unused wrapper forcing kmalloc allocation for registering nosave regions. Also, rename __register_nosave_region() to register_nosave_region() now that there is no need for disambiguation. Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com> Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-02-16tracing: Propagate is_signed to expressionTom Zanussi
commit 097f1eefedeab528cecbd35586dfe293853ffb17 upstream. During expression parsing, a new expression field is created which should inherit the properties of the operands, such as size and is_signed. is_signed propagation was missing, causing spurious errors with signed operands. Add it in parse_expr() and parse_unary() to fix the problem. Link: https://lkml.kernel.org/r/f4dac08742fd7a0920bf80a73c6c44042f5eaa40.1643319703.git.zanussi@kernel.org Cc: stable@vger.kernel.org Fixes: 100719dcef447 ("tracing: Add simple expression support to hist triggers") Reported-by: Yordan Karadzhov <ykaradzhov@vmware.com> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215513 Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> [sudip: adjust context] Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-08cgroup/cpuset: Fix "suspicious RCU usage" lockdep warningWaiman Long
commit 2bdfd2825c9662463371e6691b1a794e97fa36b4 upstream. It was found that a "suspicious RCU usage" lockdep warning was issued with the rcu_read_lock() call in update_sibling_cpumasks(). It is because the update_cpumasks_hier() function may sleep. So we have to release the RCU lock, call update_cpumasks_hier() and reacquire it afterward. Also add a percpu_rwsem_assert_held() in update_sibling_cpumasks() instead of stating that in the comment. Fixes: 4716909cc5c5 ("cpuset: Track cpusets that use parent's effective_cpus") Signed-off-by: Waiman Long <longman@redhat.com> Tested-by: Phil Auld <pauld@redhat.com> Reviewed-by: Phil Auld <pauld@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-08bpf: Use VM_MAP instead of VM_ALLOC for ringbufHou Tao
commit b293dcc473d22a62dc6d78de2b15e4f49515db56 upstream. After commit 2fd3fb0be1d1 ("kasan, vmalloc: unpoison VM_ALLOC pages after mapping"), non-VM_ALLOC mappings will be marked as accessible in __get_vm_area_node() when KASAN is enabled. But now the flag for ringbuf area is VM_ALLOC, so KASAN will complain out-of-bound access after vmap() returns. Because the ringbuf area is created by mapping allocated pages, so use VM_MAP instead. After the change, info in /proc/vmallocinfo also changes from [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmalloc user to [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmap user Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it") Reported-by: syzbot+5ad567a418794b9b5983@syzkaller.appspotmail.com Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220202060158.6260-1-houtao1@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-08audit: improve audit queue handling when "audit=1" on cmdlinePaul Moore
commit f26d04331360d42dbd6b58448bd98e4edbfbe1c5 upstream. When an admin enables audit at early boot via the "audit=1" kernel command line the audit queue behavior is slightly different; the audit subsystem goes to greater lengths to avoid dropping records, which unfortunately can result in problems when the audit daemon is forcibly stopped for an extended period of time. This patch makes a number of changes designed to improve the audit queuing behavior so that leaving the audit daemon in a stopped state for an extended period does not cause a significant impact to the system. - kauditd_send_queue() is now limited to looping through the passed queue only once per call. This not only prevents the function from looping indefinitely when records are returned to the current queue, it also allows any recovery handling in kauditd_thread() to take place when kauditd_send_queue() returns. - Transient netlink send errors seen as -EAGAIN now cause the record to be returned to the retry queue instead of going to the hold queue. The intention of the hold queue is to store, perhaps for an extended period of time, the events which led up to the audit daemon going offline. The retry queue remains a temporary queue intended to protect against transient issues between the kernel and the audit daemon. - The retry queue is now limited by the audit_backlog_limit setting, the same as the other queues. This allows admins to bound the size of all of the audit queues on the system. - kauditd_rehold_skb() now returns records to the end of the hold queue to ensure ordering is preserved in the face of recent changes to kauditd_send_queue(). Cc: stable@vger.kernel.org Fixes: 5b52330bbfe63 ("audit: fix auditd/kernel connection state tracking") Fixes: f4b3ee3c85551 ("audit: improve robustness of the audit queue handling") Reported-by: Gaosheng Cui <cuigaosheng1@huawei.com> Tested-by: Gaosheng Cui <cuigaosheng1@huawei.com> Reviewed-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-05cpuset: Fix the bug that subpart_cpus updated wrongly in update_cpumask()Tianchen Ding
commit c80d401c52a2d1baf2a5afeb06f0ffe678e56d23 upstream. subparts_cpus should be limited as a subset of cpus_allowed, but it is updated wrongly by using cpumask_andnot(). Use cpumask_and() instead to fix it. Fixes: ee8dde0cd2ce ("cpuset: Add new v2 cpuset.sched.partition flag") Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com> Reviewed-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-05cgroup-v1: Require capabilities to set release_agentEric W. Biederman
commit 24f6008564183aa120d07c03d9289519c2fe02af upstream. The cgroup release_agent is called with call_usermodehelper. The function call_usermodehelper starts the release_agent with a full set fo capabilities. Therefore require capabilities when setting the release_agaent. Reported-by: Tabitha Sable <tabitha.c.sable@gmail.com> Tested-by: Tabitha Sable <tabitha.c.sable@gmail.com> Fixes: 81a6a5cdd2c5 ("Task Control Groups: automatic userspace notification of idle cgroups") Cc: stable@vger.kernel.org # v2.6.24+ Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-05psi: Fix uaf issue when psi trigger is destroyed while being polledSuren Baghdasaryan
commit a06247c6804f1a7c86a2e5398a4c1f1db1471848 upstream. With write operation on psi files replacing old trigger with a new one, the lifetime of its waitqueue is totally arbitrary. Overwriting an existing trigger causes its waitqueue to be freed and pending poll() will stumble on trigger->event_wait which was destroyed. Fix this by disallowing to redefine an existing psi trigger. If a write operation is used on a file descriptor with an already existing psi trigger, the operation will fail with EBUSY error. Also bypass a check for psi_disabled in the psi_trigger_destroy as the flag can be flipped after the trigger is created, leading to a memory leak. Fixes: 0e94682b73bf ("psi: introduce psi monitor") Reported-by: syzbot+cdb5dd11c97cc532efad@syzkaller.appspotmail.com Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Analyzed-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Eric Biggers <ebiggers@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220111232309.1786347-1-surenb@google.com [surenb: backported to 5.10 kernel] CC: stable@vger.kernel.org # 5.10 Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-01sched/pelt: Relax the sync of util_sum with util_avgVincent Guittot
[ Upstream commit 98b0d890220d45418cfbc5157b3382e6da5a12ab ] Rick reported performance regressions in bugzilla because of cpu frequency being lower than before: https://bugzilla.kernel.org/show_bug.cgi?id=215045 He bisected the problem to: commit 1c35b07e6d39 ("sched/fair: Ensure _sum and _avg values stay consistent") This commit forces util_sum to be synced with the new util_avg after removing the contribution of a task and before the next periodic sync. By doing so util_sum is rounded to its lower bound and might lost up to LOAD_AVG_MAX-1 of accumulated contribution which has not yet been reflected in util_avg. Instead of always setting util_sum to the low bound of util_avg, which can significantly lower the utilization of root cfs_rq after propagating the change down into the hierarchy, we revert the change of util_sum and propagate the difference. In addition, we also check that cfs's util_sum always stays above the lower bound for a given util_avg as it has been observed that sched_entity's util_sum is sometimes above cfs one. Fixes: 1c35b07e6d39 ("sched/fair: Ensure _sum and _avg values stay consistent") Reported-by: Rick Yiu <rickyiu@google.com> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Tested-by: Sachin Sant <sachinp@linux.ibm.com> Link: https://lkml.kernel.org/r/20220111134659.24961-2-vincent.guittot@linaro.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-02-01perf: Fix perf_event_read_local() timePeter Zijlstra
[ Upstream commit 09f5e7dc7ad705289e1b1ec065439aa3c42951c4 ] Time readers that cannot take locks (due to NMI etc..) currently make use of perf_event::shadow_ctx_time, which, for that event gives: time' = now + (time - timestamp) or, alternatively arranged: time' = time + (now - timestamp) IOW, the progression of time since the last time the shadow_ctx_time was updated. There's problems with this: A) the shadow_ctx_time is per-event, even though the ctx_time it reflects is obviously per context. The direct concequence of this is that the context needs to iterate all events all the time to keep the shadow_ctx_time in sync. B) even with the prior point, the context itself might not be active meaning its time should not advance to begin with. C) shadow_ctx_time isn't consistently updated when ctx_time is There are 3 users of this stuff, that suffer differently from this: - calc_timer_values() - perf_output_read() - perf_event_update_userpage() /* A */ - perf_event_read_local() /* A,B */ In particular, perf_output_read() doesn't suffer at all, because it's sample driven and hence only relevant when the event is actually running. This same was supposed to be true for perf_event_update_userpage(), after all self-monitoring implies the context is active *HOWEVER*, as per commit f79256532682 ("perf/core: fix userpage->time_enabled of inactive events") this goes wrong when combined with counter overcommit, in that case those events that do not get scheduled when the context becomes active (task events typically) miss out on the EVENT_TIME update and ENABLED time is inflated (for a little while) with the time the context was inactive. Once the event gets rotated in, this gets corrected, leading to a non-monotonic timeflow. perf_event_read_local() made things even worse, it can request time at any point, suffering all the problems perf_event_update_userpage() does and more. Because while perf_event_update_userpage() is limited by the context being active, perf_event_read_local() users have no such constraint. Therefore, completely overhaul things and do away with perf_event::shadow_ctx_time. Instead have regular context time updates keep track of this offset directly and provide perf_event_time_now() to complement perf_event_time(). perf_event_time_now() will, in adition to being context wide, also take into account if the context is active. For inactive context, it will not advance time. This latter property means the cgroup perf_cgroup_info context needs to grow addition state to track this. Additionally, since all this is strictly per-cpu, we can use barrier() to order context activity vs context time. Fixes: 7d9285e82db5 ("perf/bpf: Extend the perf_event_read_local() interface, a.k.a. "bpf: perf event change needed for subsequent bpf helpers"") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Song Liu <song@kernel.org> Tested-by: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/r/YcB06DasOBtU0b00@hirez.programming.kicks-ass.net Signed-off-by: Sasha Levin <sashal@kernel.org>
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