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2017-07-27alarmtimer: don't rate limit one-shot timersGreg Hackmann
Commit ff86bf0c65f1 ("alarmtimer: Rate limit periodic intervals") sets a minimum bound on the alarm timer interval. This minimum bound shouldn't be applied if the interval is 0. Otherwise, one-shot timers will be converted into periodic ones. Fixes: ff86bf0c65f1 ("alarmtimer: Rate limit periodic intervals") Reported-by: Ben Fennema <fennema@google.com> Signed-off-by: Greg Hackmann <ghackmann@google.com> Cc: stable@vger.kernel.org Cc: John Stultz <john.stultz@linaro.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-27tracing: Fix kmemleak in instance_rmdirChunyu Hu
commit db9108e054700c96322b0f0028546aa4e643cf0b upstream. Hit the kmemleak when executing instance_rmdir, it forgot releasing mem of tracing_cpumask. With this fix, the warn does not appear any more. unreferenced object 0xffff93a8dfaa7c18 (size 8): comm "mkdir", pid 1436, jiffies 4294763622 (age 9134.308s) hex dump (first 8 bytes): ff ff ff ff ff ff ff ff ........ backtrace: [<ffffffff88b6567a>] kmemleak_alloc+0x4a/0xa0 [<ffffffff8861ea41>] __kmalloc_node+0xf1/0x280 [<ffffffff88b505d3>] alloc_cpumask_var_node+0x23/0x30 [<ffffffff88b5060e>] alloc_cpumask_var+0xe/0x10 [<ffffffff88571ab0>] instance_mkdir+0x90/0x240 [<ffffffff886e5100>] tracefs_syscall_mkdir+0x40/0x70 [<ffffffff886565c9>] vfs_mkdir+0x109/0x1b0 [<ffffffff8865b1d0>] SyS_mkdir+0xd0/0x100 [<ffffffff88403857>] do_syscall_64+0x67/0x150 [<ffffffff88b710e7>] return_from_SYSCALL_64+0x0/0x6a [<ffffffffffffffff>] 0xffffffffffffffff Link: http://lkml.kernel.org/r/1500546969-12594-1-git-send-email-chuhu@redhat.com Fixes: ccfe9e42e451 ("tracing: Make tracing_cpumask available for all instances") Signed-off-by: Chunyu Hu <chuhu@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-27Revert "perf/core: Drop kernel samples even though :u is specified"Ingo Molnar
commit 6a8a75f3235724c5941a33e287b2f98966ad14c5 upstream. This reverts commit cc1582c231ea041fbc68861dfaf957eaf902b829. This commit introduced a regression that broke rr-project, which uses sampling events to receive a signal on overflow (but does not care about the contents of the sample). These signals are critical to the correct operation of rr. There's been some back and forth about how to fix it - but to not keep applications in limbo queue up a revert. Reported-by: Kyle Huey <me@kylehuey.com> Acked-by: Kyle Huey <me@kylehuey.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Stephane Eranian <eranian@google.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Link: http://lkml.kernel.org/r/20170628105600.GC5981@leverpostej Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-21tracing: Use SOFTIRQ_OFFSET for softirq dectection for more accurate resultsPavankumar Kondeti
commit c59f29cb144a6a0dfac16ede9dc8eafc02dc56ca upstream. The 's' flag is supposed to indicate that a softirq is running. This can be detected by testing the preempt_count with SOFTIRQ_OFFSET. The current code tests the preempt_count with SOFTIRQ_MASK, which would be true even when softirqs are disabled but not serving a softirq. Link: http://lkml.kernel.org/r/1481300417-3564-1-git-send-email-pkondeti@codeaurora.org Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-21sched/topology: Fix overlapping sched_group_maskPeter Zijlstra
commit 73bb059f9b8a00c5e1bf2f7ca83138c05d05e600 upstream. The point of sched_group_mask is to select those CPUs from sched_group_cpus that can actually arrive at this balance domain. The current code gets it wrong, as can be readily demonstrated with a topology like: node 0 1 2 3 0: 10 20 30 20 1: 20 10 20 30 2: 30 20 10 20 3: 20 30 20 10 Where (for example) domain 1 on CPU1 ends up with a mask that includes CPU0: [] CPU1 attaching sched-domain: [] domain 0: span 0-2 level NUMA [] groups: 1 (mask: 1), 2, 0 [] domain 1: span 0-3 level NUMA [] groups: 0-2 (mask: 0-2) (cpu_capacity: 3072), 0,2-3 (cpu_capacity: 3072) This causes sched_balance_cpu() to compute the wrong CPU and consequently should_we_balance() will terminate early resulting in missed load-balance opportunities. The fixed topology looks like: [] CPU1 attaching sched-domain: [] domain 0: span 0-2 level NUMA [] groups: 1 (mask: 1), 2, 0 [] domain 1: span 0-3 level NUMA [] groups: 0-2 (mask: 1) (cpu_capacity: 3072), 0,2-3 (cpu_capacity: 3072) (note: this relies on OVERLAP domains to always have children, this is true because the regular topology domains are still here -- this is before degenerate trimming) Debugged-by: Lauro Ramos Venancio <lvenanci@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Fixes: e3589f6c81e4 ("sched: Allow for overlapping sched_domain spans") Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-21sched/topology: Optimize build_group_mask()Lauro Ramos Venancio
commit f32d782e31bf079f600dcec126ed117b0577e85c upstream. The group mask is always used in intersection with the group CPUs. So, when building the group mask, we don't have to care about CPUs that are not part of the group. Signed-off-by: Lauro Ramos Venancio <lvenanci@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: lwang@redhat.com Cc: riel@redhat.com Link: http://lkml.kernel.org/r/1492717903-5195-2-git-send-email-lvenanci@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-21kernel/extable.c: mark core_kernel_text notraceMarcin Nowakowski
commit c0d80ddab89916273cb97114889d3f337bc370ae upstream. core_kernel_text is used by MIPS in its function graph trace processing, so having this method traced leads to an infinite set of recursive calls such as: Call Trace: ftrace_return_to_handler+0x50/0x128 core_kernel_text+0x10/0x1b8 prepare_ftrace_return+0x6c/0x114 ftrace_graph_caller+0x20/0x44 return_to_handler+0x10/0x30 return_to_handler+0x0/0x30 return_to_handler+0x0/0x30 ftrace_ops_no_ops+0x114/0x1bc core_kernel_text+0x10/0x1b8 core_kernel_text+0x10/0x1b8 core_kernel_text+0x10/0x1b8 ftrace_ops_no_ops+0x114/0x1bc core_kernel_text+0x10/0x1b8 prepare_ftrace_return+0x6c/0x114 ftrace_graph_caller+0x20/0x44 (...) Mark the function notrace to avoid it being traced. Link: http://lkml.kernel.org/r/1498028607-6765-1-git-send-email-marcin.nowakowski@imgtec.com Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Meyer <thomas@m3y3r.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-15tracing/kprobes: Allow to create probe with a module name starting with a digitSabrina Dubroca
commit 9e52b32567126fe146f198971364f68d3bc5233f upstream. Always try to parse an address, since kstrtoul() will safely fail when given a symbol as input. If that fails (which will be the case for a symbol), try to parse a symbol instead. This allows creating a probe such as: p:probe/vlan_gro_receive 8021q:vlan_gro_receive+0 Which is necessary for this command to work: perf probe -m 8021q -a vlan_gro_receive Link: http://lkml.kernel.org/r/fd72d666f45b114e2c5b9cf7e27b91de1ec966f1.1498122881.git.sd@queasysnail.net Fixes: 413d37d1e ("tracing: Add kprobe-based event tracer") Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-05sysctl: enable strict writesKees Cook
commit 41662f5cc55335807d39404371cfcbb1909304c4 upstream. SYSCTL_WRITES_WARN was added in commit f4aacea2f5d1 ("sysctl: allow for strict write position handling"), and released in v3.16 in August of 2014. Since then I can find only 1 instance of non-zero offset writing[1], and it was fixed immediately in CRIU[2]. As such, it appears safe to flip this to the strict state now. [1] https://www.google.com/search?q="when%20file%20position%20was%20not%200" [2] http://lists.openvz.org/pipermail/criu/2015-April/019819.html Signed-off-by: Kees Cook <keescook@chromium.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Sumit Semwal <sumit.semwal@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-29signal: Only reschedule timers on signals timers have sentEric W. Biederman
commit 57db7e4a2d92c2d3dfbca4ef8057849b2682436b upstream. Thomas Gleixner wrote: > The CRIU support added a 'feature' which allows a user space task to send > arbitrary (kernel) signals to itself. The changelog says: > > The kernel prevents sending of siginfo with positive si_code, because > these codes are reserved for kernel. I think we can allow a task to > send such a siginfo to itself. This operation should not be dangerous. > > Quite contrary to that claim, it turns out that it is outright dangerous > for signals with info->si_code == SI_TIMER. The following code sequence in > a user space task allows to crash the kernel: > > id = timer_create(CLOCK_XXX, ..... signo = SIGX); > timer_set(id, ....); > info->si_signo = SIGX; > info->si_code = SI_TIMER: > info->_sifields._timer._tid = id; > info->_sifields._timer._sys_private = 2; > rt_[tg]sigqueueinfo(..., SIGX, info); > sigemptyset(&sigset); > sigaddset(&sigset, SIGX); > rt_sigtimedwait(sigset, info); > > For timers based on CLOCK_PROCESS_CPUTIME_ID, CLOCK_THREAD_CPUTIME_ID this > results in a kernel crash because sigwait() dequeues the signal and the > dequeue code observes: > > info->si_code == SI_TIMER && info->_sifields._timer._sys_private != 0 > > which triggers the following callchain: > > do_schedule_next_timer() -> posix_cpu_timer_schedule() -> arm_timer() > > arm_timer() executes a list_add() on the timer, which is already armed via > the timer_set() syscall. That's a double list add which corrupts the posix > cpu timer list. As a consequence the kernel crashes on the next operation > touching the posix cpu timer list. > > Posix clocks which are internally implemented based on hrtimers are not > affected by this because hrtimer_start() can handle already armed timers > nicely, but it's a reliable way to trigger the WARN_ON() in > hrtimer_forward(), which complains about calling that function on an > already armed timer. This problem has existed since the posix timer code was merged into 2.5.63. A few releases earlier in 2.5.60 ptrace gained the ability to inject not just a signal (which linux has supported since 1.0) but the full siginfo of a signal. The core problem is that the code will reschedule in response to signals getting dequeued not just for signals the timers sent but for other signals that happen to a si_code of SI_TIMER. Avoid this confusion by testing to see if the queued signal was preallocated as all timer signals are preallocated, and so far only the timer code preallocates signals. Move the check for if a timer needs to be rescheduled up into collect_signal where the preallocation check must be performed, and pass the result back to dequeue_signal where the code reschedules timers. This makes it clear why the code cares about preallocated timers. Reported-by: Thomas Gleixner <tglx@linutronix.de> History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Reference: 66dd34ad31e5 ("signal: allow to send any siginfo to itself") Reference: 1669ce53e2ff ("Add PTRACE_GETSIGINFO and PTRACE_SETSIGINFO") Fixes: db8b50ba75f2 ("[PATCH] POSIX clocks & timers") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-26alarmtimer: Rate limit periodic intervalsThomas Gleixner
commit ff86bf0c65f14346bf2440534f9ba5ac232c39a0 upstream. The alarmtimer code has another source of potentially rearming itself too fast. Interval timers with a very samll interval have a similar CPU hog effect as the previously fixed overflow issue. The reason is that alarmtimers do not implement the normal protection against this kind of problem which the other posix timer use: timer expires -> queue signal -> deliver signal -> rearm timer This scheme brings the rearming under scheduler control and prevents permanently firing timers which hog the CPU. Bringing this scheme to the alarm timer code is a major overhaul because it lacks all the necessary mechanisms completely. So for a quick fix limit the interval to one jiffie. This is not problematic in practice as alarmtimers are usually backed by an RTC for suspend which have 1 second resolution. It could be therefor argued that the resolution of this clock should be set to 1 second in general, but that's outside the scope of this fix. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kostya Serebryany <kcc@google.com> Cc: syzkaller <syzkaller@googlegroups.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Dmitry Vyukov <dvyukov@google.com> Link: http://lkml.kernel.org/r/20170530211655.896767100@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-26genirq: Release resources in __setup_irq() error pathHeiner Kallweit
commit fa07ab72cbb0d843429e61bf179308aed6cbe0dd upstream. In case __irq_set_trigger() fails the resources requested via irq_request_resources() are not released. Add the missing release call into the error handling path. Fixes: c1bacbae8192 ("genirq: Provide irq_request/release_resources chip callbacks") Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/655538f5-cb20-a892-ff15-fbd2dd1fa4ec@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-14perf/core: Drop kernel samples even though :u is specifiedJin Yao
commit cc1582c231ea041fbc68861dfaf957eaf902b829 upstream. When doing sampling, for example: perf record -e cycles:u ... On workloads that do a lot of kernel entry/exits we see kernel samples, even though :u is specified. This is due to skid existing. This might be a security issue because it can leak kernel addresses even though kernel sampling support is disabled. The patch drops the kernel samples if exclude_kernel is specified. For example, test on Haswell desktop: perf record -e cycles:u <mgen> perf report --stdio Before patch applied: 99.77% mgen mgen [.] buf_read 0.20% mgen mgen [.] rand_buf_init 0.01% mgen [kernel.vmlinux] [k] apic_timer_interrupt 0.00% mgen mgen [.] last_free_elem 0.00% mgen libc-2.23.so [.] __random_r 0.00% mgen libc-2.23.so [.] _int_malloc 0.00% mgen mgen [.] rand_array_init 0.00% mgen [kernel.vmlinux] [k] page_fault 0.00% mgen libc-2.23.so [.] __random 0.00% mgen libc-2.23.so [.] __strcasestr 0.00% mgen ld-2.23.so [.] strcmp 0.00% mgen ld-2.23.so [.] _dl_start 0.00% mgen libc-2.23.so [.] sched_setaffinity@@GLIBC_2.3.4 0.00% mgen ld-2.23.so [.] _start We can see kernel symbols apic_timer_interrupt and page_fault. After patch applied: 99.79% mgen mgen [.] buf_read 0.19% mgen mgen [.] rand_buf_init 0.00% mgen libc-2.23.so [.] __random_r 0.00% mgen mgen [.] rand_array_init 0.00% mgen mgen [.] last_free_elem 0.00% mgen libc-2.23.so [.] vfprintf 0.00% mgen libc-2.23.so [.] rand 0.00% mgen libc-2.23.so [.] __random 0.00% mgen libc-2.23.so [.] _int_malloc 0.00% mgen libc-2.23.so [.] _IO_doallocbuf 0.00% mgen ld-2.23.so [.] do_lookup_x 0.00% mgen ld-2.23.so [.] open_verify.constprop.7 0.00% mgen ld-2.23.so [.] _dl_important_hwcaps 0.00% mgen libc-2.23.so [.] sched_setaffinity@@GLIBC_2.3.4 0.00% mgen ld-2.23.so [.] _start There are only userspace symbols. Signed-off-by: Jin Yao <yao.jin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: acme@kernel.org Cc: jolsa@kernel.org Cc: kan.liang@intel.com Cc: mark.rutland@arm.com Cc: will.deacon@arm.com Cc: yao.jin@intel.com Link: http://lkml.kernel.org/r/1495706947-3744-1-git-send-email-yao.jin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-14stackprotector: Increase the per-task stack canary's random range from 32 ↵Daniel Micay
bits to 64 bits on 64-bit platforms commit 5ea30e4e58040cfd6434c2f33dc3ea76e2c15b05 upstream. The stack canary is an 'unsigned long' and should be fully initialized to random data rather than only 32 bits of random data. Signed-off-by: Daniel Micay <danielmicay@gmail.com> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Arjan van Ven <arjan@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-hardening@lists.openwall.com Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20170504133209.3053-1-danielmicay@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-07Revert "stackprotector: Increase the per-task stack canary's random range ↵Greg Kroah-Hartman
from 32 bits to 64 bits on 64-bit platforms" This reverts commit 609a3e81550b0b4ea87197b0f59455a7bcff975a which is commit 5ea30e4e58040cfd6434c2f33dc3ea76e2c15b05 upstream. It shouldn't have been backported to 3.18, as we do not have get_random_long() in that kernel tree. Reported-by: Philip Müller <philm@manjaro.org> Cc: Daniel Micay <danielmicay@gmail.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Arjan van Ven <arjan@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-hardening@lists.openwall.com Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-25tracing/kprobes: Enforce kprobes teardown after testingThomas Gleixner
commit 30e7d894c1478c88d50ce94ddcdbd7f9763d9cdd upstream. Enabling the tracer selftest triggers occasionally the warning in text_poke(), which warns when the to be modified page is not marked reserved. The reason is that the tracer selftest installs kprobes on functions marked __init for testing. These probes are removed after the tests, but that removal schedules the delayed kprobes_optimizer work, which will do the actual text poke. If the work is executed after the init text is freed, then the warning triggers. The bug can be reproduced reliably when the work delay is increased. Flush the optimizer work and wait for the optimizing/unoptimizing lists to become empty before returning from the kprobes tracer selftest. That ensures that all operations which were queued due to the probes removal have completed. Link: http://lkml.kernel.org/r/20170516094802.76a468bb@gandalf.local.home Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Fixes: 6274de498 ("kprobes: Support delayed unoptimizing") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-25stackprotector: Increase the per-task stack canary's random range from 32 ↵Daniel Micay
bits to 64 bits on 64-bit platforms commit 5ea30e4e58040cfd6434c2f33dc3ea76e2c15b05 upstream. The stack canary is an 'unsigned long' and should be fully initialized to random data rather than only 32 bits of random data. Signed-off-by: Daniel Micay <danielmicay@gmail.com> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Arjan van Ven <arjan@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-hardening@lists.openwall.com Link: http://lkml.kernel.org/r/20170504133209.3053-1-danielmicay@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-25pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processesEric W. Biederman
commit b9a985db98961ae1ba0be169f19df1c567e4ffe0 upstream. The code can potentially sleep for an indefinite amount of time in zap_pid_ns_processes triggering the hung task timeout, and increasing the system average. This is undesirable. Sleep with a task state of TASK_INTERRUPTIBLE instead of TASK_UNINTERRUPTIBLE to remove these undesirable side effects. Apparently under heavy load this has been allowing Chrome to trigger the hung time task timeout error and cause ChromeOS to reboot. Reported-by: Vovo Yang <vovoy@google.com> Reported-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Fixes: 6347e9009104 ("pidns: guarantee that the pidns init will be the last pidns process reaped") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-20sched: panic on corrupted stack endJann Horn
commit 29d6455178a09e1dc340380c582b13356227e8df upstream. Until now, hitting this BUG_ON caused a recursive oops (because oops handling involves do_exit(), which calls into the scheduler, which in turn raises an oops), which caused stuff below the stack to be overwritten until a panic happened (e.g. via an oops in interrupt context, caused by the overwritten CPU index in the thread_info). Just panic directly. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [AmitP: Minor refactoring of upstream changes for linux-3.18.y] Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-20perf: Fix race in swevent hashPeter Zijlstra
commit 12ca6ad2e3a896256f086497a7c7406a547ee373 upstream. There's a race on CPU unplug where we free the swevent hash array while it can still have events on. This will result in a use-after-free which is BAD. Simply do not free the hash array on unplug. This leaves the thing around and no use-after-free takes place. When the last swevent dies, we do a for_each_possible_cpu() iteration anyway to clean these up, at which time we'll free it, so no leakage will occur. Reported-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-20perf: Fix event->ctx lockingPeter Zijlstra
commit f63a8daa5812afef4f06c962351687e1ff9ccb2b upstream. There have been a few reported issues wrt. the lack of locking around changing event->ctx. This patch tries to address those. It avoids the whole rwsem thing; and while it appears to work, please give it some thought in review. What I did fail at is sensible runtime checks on the use of event->ctx, the RCU use makes it very hard. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20150123125834.209535886@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-20padata: free correct variableJason A. Donenfeld
commit 07a77929ba672d93642a56dc2255dd21e6e2290b upstream. The author meant to free the variable that was just allocated, instead of the one that failed to be allocated, but made a simple typo. This patch rectifies that. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-08perf: Tighten (and fix) the grouping conditionPeter Zijlstra
commit c3c87e770458aa004bd7ed3f29945ff436fd6511 upstream. The fix from 9fc81d87420d ("perf: Fix events installation during moving group") was incomplete in that it failed to recognise that creating a group with events for different CPUs is semantically broken -- they cannot be co-scheduled. Furthermore, it leads to real breakage where, when we create an event for CPU Y and then migrate it to form a group on CPU X, the code gets confused where the counter is programmed -- triggered in practice as well by me via the perf fuzzer. Fix this by tightening the rules for creating groups. Only allow grouping of counters that can be co-scheduled in the same context. This means for the same task and/or the same cpu. Fixes: 9fc81d87420d ("perf: Fix events installation during moving group") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20150123125834.090683288@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-30kconfig: tinyconfig: provide whole choice blocks to avoid warningsArnd Bergmann
commit 236dec051078a8691950f56949612b4b74107e48 upstream. Using "make tinyconfig" produces a couple of annoying warnings that show up for build test machines all the time: .config:966:warning: override: NOHIGHMEM changes choice state .config:965:warning: override: SLOB changes choice state .config:963:warning: override: KERNEL_XZ changes choice state .config:962:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state .config:933:warning: override: SLOB changes choice state .config:930:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state .config:870:warning: override: SLOB changes choice state .config:868:warning: override: KERNEL_XZ changes choice state .config:867:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state I've made a previous attempt at fixing them and we discussed a number of alternatives. I tried changing the Makefile to use "merge_config.sh -n $(fragment-list)" but couldn't get that to work properly. This is yet another approach, based on the observation that we do want to see a warning for conflicting 'choice' options, and that we can simply make them non-conflicting by listing all other options as disabled. This is a trivial patch that we can apply independent of plans for other changes. Link: http://lkml.kernel.org/r/20160829214952.1334674-2-arnd@arndb.de Link: https://storage.kernelci.org/mainline/v4.7-rc6/x86-tinyconfig/build.log https://patchwork.kernel.org/patch/9212749/ Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-30perf: Avoid horrible stack usagePeter Zijlstra (Intel)
commit 86038c5ea81b519a8a1fcfcd5e4599aab0cdd119 upstream. Both Linus (most recent) and Steve (a while ago) reported that perf related callbacks have massive stack bloat. The problem is that software events need a pt_regs in order to properly report the event location and unwind stack. And because we could not assume one was present we allocated one on stack and filled it with minimal bits required for operation. Now, pt_regs is quite large, so this is undesirable. Furthermore it turns out that most sites actually have a pt_regs pointer available, making this even more onerous, as the stack space is pointless waste. This patch addresses the problem by observing that software events have well defined nesting semantics, therefore we can use static per-cpu storage instead of on-stack. Linus made the further observation that all but the scheduler callers of perf_sw_event() have a pt_regs available, so we change the regular perf_sw_event() to require a valid pt_regs (where it used to be optional) and add perf_sw_event_sched() for the scheduler. We have a scheduler specific call instead of a more generic _noregs() like construct because we can assume non-recursion from the scheduler and thereby simplify the code further (_noregs would have to put the recursion context call inline in order to assertain which __perf_regs element to use). One last note on the implementation of perf_trace_buf_prepare(); we allow .regs = NULL for those cases where we already have a pt_regs pointer available and do not need another. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Javi Merino <javi.merino@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Petr Mladek <pmladek@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Vaibhav Nagarnaik <vnagarnaik@google.com> Link: http://lkml.kernel.org/r/20141216115041.GW3337@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-30ring-buffer: Have ring_buffer_iter_empty() return true when emptySteven Rostedt (VMware)
commit 78f7a45dac2a2d2002f98a3a95f7979867868d73 upstream. I noticed that reading the snapshot file when it is empty no longer gives a status. It suppose to show the status of the snapshot buffer as well as how to allocate and use it. For example: ># cat snapshot # tracer: nop # # # * Snapshot is allocated * # # Snapshot commands: # echo 0 > snapshot : Clears and frees snapshot buffer # echo 1 > snapshot : Allocates snapshot buffer, if not already allocated. # Takes a snapshot of the main buffer. # echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free) # (Doesn't have to be '2' works with any number that # is not a '0' or '1') But instead it just showed an empty buffer: ># cat snapshot # tracer: nop # # entries-in-buffer/entries-written: 0/0 #P:4 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | What happened was that it was using the ring_buffer_iter_empty() function to see if it was empty, and if it was, it showed the status. But that function was returning false when it was empty. The reason was that the iter header page was on the reader page, and the reader page was empty, but so was the buffer itself. The check only tested to see if the iter was on the commit page, but the commit page was no longer pointing to the reader page, but as all pages were empty, the buffer is also. Fixes: 651e22f2701b ("ring-buffer: Always reset iterator to reader page") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-30tracing: Allocate the snapshot buffer before enabling probeSteven Rostedt (VMware)
commit df62db5be2e5f070ecd1a5ece5945b590ee112e0 upstream. Currently the snapshot trigger enables the probe and then allocates the snapshot. If the probe triggers before the allocation, it could cause the snapshot to fail and turn tracing off. It's best to allocate the snapshot buffer first, and then enable the trigger. If something goes wrong in the enabling of the trigger, the snapshot buffer is still allocated, but it can also be freed by the user by writting zero into the snapshot buffer file. Also add a check of the return status of alloc_snapshot(). Fixes: 77fd5c15e3 ("tracing: Add snapshot trigger to function probes") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-22ring-buffer: Fix return value check in test_ringbuffer()Wei Yongjun
commit 62277de758b155dc04b78f195a1cb5208c37b2df upstream. In case of error, the function kthread_run() returns ERR_PTR() and never returns NULL. The NULL test in the return value check should be replaced with IS_ERR(). Link: http://lkml.kernel.org/r/1466184839-14927-1-git-send-email-weiyj_lk@163.com Fixes: 6c43e554a ("ring-buffer: Add ring buffer startup selftest") Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-22perf/core: Fix event inheritance on fork()Peter Zijlstra
commit e7cc4865f0f31698ef2f7aac01a50e78968985b7 upstream. While hunting for clues to a use-after-free, Oleg spotted that perf_event_init_context() can loose an error value with the result that fork() can succeed even though we did not fully inherit the perf event context. Spotted-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: oleg@redhat.com Fixes: 889ff0150661 ("perf/core: Split context's event group list into pinned and non-pinned lists") Link: http://lkml.kernel.org/r/20170316125823.190342547@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-22ptrace: fix PTRACE_LISTEN race corrupting task->statebsegall@google.com
commit 5402e97af667e35e54177af8f6575518bf251d51 upstream. In PT_SEIZED + LISTEN mode STOP/CONT signals cause a wakeup against __TASK_TRACED. If this races with the ptrace_unfreeze_traced at the end of a PTRACE_LISTEN, this can wake the task /after/ the check against __TASK_TRACED, but before the reset of state to TASK_TRACED. This causes it to instead clobber TASK_WAKING, allowing a subsequent wakeup against TRACED while the task is still on the rq wake_list, corrupting it. Oleg said: "The kernel can crash or this can lead to other hard-to-debug problems. In short, "task->state = TASK_TRACED" in ptrace_unfreeze_traced() assumes that nobody else can wake it up, but PTRACE_LISTEN breaks the contract. Obviusly it is very wrong to manipulate task->state if this task is already running, or WAKING, or it sleeps again" [akpm@linux-foundation.org: coding-style fixes] Fixes: 9899d11f ("ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL") Link: http://lkml.kernel.org/r/xm26y3vfhmkp.fsf_-_@bsegall-linux.mtv.corp.google.com Signed-off-by: Ben Segall <bsegall@google.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-22ftrace: Fix removing of second function probeSteven Rostedt (VMware)
commit 82cc4fc2e70ec5baeff8f776f2773abc8b2cc0ae upstream. When two function probes are added to set_ftrace_filter, and then one of them is removed, the update to the function locations is not performed, and the record keeping of the function states are corrupted, and causes an ftrace_bug() to occur. This is easily reproducable by adding two probes, removing one, and then adding it back again. # cd /sys/kernel/debug/tracing # echo schedule:traceoff > set_ftrace_filter # echo do_IRQ:traceoff > set_ftrace_filter # echo \!do_IRQ:traceoff > /debug/tracing/set_ftrace_filter # echo do_IRQ:traceoff > set_ftrace_filter Causes: ------------[ cut here ]------------ WARNING: CPU: 2 PID: 1098 at kernel/trace/ftrace.c:2369 ftrace_get_addr_curr+0x143/0x220 Modules linked in: [...] CPU: 2 PID: 1098 Comm: bash Not tainted 4.10.0-test+ #405 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012 Call Trace: dump_stack+0x68/0x9f __warn+0x111/0x130 ? trace_irq_work_interrupt+0xa0/0xa0 warn_slowpath_null+0x1d/0x20 ftrace_get_addr_curr+0x143/0x220 ? __fentry__+0x10/0x10 ftrace_replace_code+0xe3/0x4f0 ? ftrace_int3_handler+0x90/0x90 ? printk+0x99/0xb5 ? 0xffffffff81000000 ftrace_modify_all_code+0x97/0x110 arch_ftrace_update_code+0x10/0x20 ftrace_run_update_code+0x1c/0x60 ftrace_run_modify_code.isra.48.constprop.62+0x8e/0xd0 register_ftrace_function_probe+0x4b6/0x590 ? ftrace_startup+0x310/0x310 ? debug_lockdep_rcu_enabled.part.4+0x1a/0x30 ? update_stack_state+0x88/0x110 ? ftrace_regex_write.isra.43.part.44+0x1d3/0x320 ? preempt_count_sub+0x18/0xd0 ? mutex_lock_nested+0x104/0x800 ? ftrace_regex_write.isra.43.part.44+0x1d3/0x320 ? __unwind_start+0x1c0/0x1c0 ? _mutex_lock_nest_lock+0x800/0x800 ftrace_trace_probe_callback.isra.3+0xc0/0x130 ? func_set_flag+0xe0/0xe0 ? __lock_acquire+0x642/0x1790 ? __might_fault+0x1e/0x20 ? trace_get_user+0x398/0x470 ? strcmp+0x35/0x60 ftrace_trace_onoff_callback+0x48/0x70 ftrace_regex_write.isra.43.part.44+0x251/0x320 ? match_records+0x420/0x420 ftrace_filter_write+0x2b/0x30 __vfs_write+0xd7/0x330 ? do_loop_readv_writev+0x120/0x120 ? locks_remove_posix+0x90/0x2f0 ? do_lock_file_wait+0x160/0x160 ? __lock_is_held+0x93/0x100 ? rcu_read_lock_sched_held+0x5c/0xb0 ? preempt_count_sub+0x18/0xd0 ? __sb_start_write+0x10a/0x230 ? vfs_write+0x222/0x240 vfs_write+0xef/0x240 SyS_write+0xab/0x130 ? SyS_read+0x130/0x130 ? trace_hardirqs_on_caller+0x182/0x280 ? trace_hardirqs_on_thunk+0x1a/0x1c entry_SYSCALL_64_fastpath+0x18/0xad RIP: 0033:0x7fe61c157c30 RSP: 002b:00007ffe87890258 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: ffffffff8114a410 RCX: 00007fe61c157c30 RDX: 0000000000000010 RSI: 000055814798f5e0 RDI: 0000000000000001 RBP: ffff8800c9027f98 R08: 00007fe61c422740 R09: 00007fe61ca53700 R10: 0000000000000073 R11: 0000000000000246 R12: 0000558147a36400 R13: 00007ffe8788f160 R14: 0000000000000024 R15: 00007ffe8788f15c ? trace_hardirqs_off_caller+0xc0/0x110 ---[ end trace 99fa09b3d9869c2c ]--- Bad trampoline accounting at: ffffffff81cc3b00 (do_IRQ+0x0/0x150) Fixes: 59df055f1991 ("ftrace: trace different functions with a different tracer") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-18futex: Add missing error handling to FUTEX_REQUEUE_PIPeter Zijlstra
commit 9bbb25afeb182502ca4f2c4f3f88af0681b34cae upstream. Thomas spotted that fixup_pi_state_owner() can return errors and we fail to unlock the rt_mutex in that case. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Darren Hart <dvhart@linux.intel.com> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: dvhart@infradead.org Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170304093558.867401760@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-18futex: Fix potential use-after-free in FUTEX_REQUEUE_PIPeter Zijlstra
commit c236c8e95a3d395b0494e7108f0d41cf36ec107c upstream. While working on the futex code, I stumbled over this potential use-after-free scenario. Dmitry triggered it later with syzkaller. pi_mutex is a pointer into pi_state, which we drop the reference on in unqueue_me_pi(). So any access to that pointer after that is bad. Since other sites already do rt_mutex_unlock() with hb->lock held, see for example futex_lock_pi(), simply move the unlock before unqueue_me_pi(). Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Darren Hart <dvhart@linux.intel.com> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: dvhart@infradead.org Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170304093558.801744246@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-18padata: avoid race in reorderingJason A. Donenfeld
commit de5540d088fe97ad583cc7d396586437b32149a5 upstream. Under extremely heavy uses of padata, crashes occur, and with list debugging turned on, this happens instead: [87487.298728] WARNING: CPU: 1 PID: 882 at lib/list_debug.c:33 __list_add+0xae/0x130 [87487.301868] list_add corruption. prev->next should be next (ffffb17abfc043d0), but was ffff8dba70872c80. (prev=ffff8dba70872b00). [87487.339011] [<ffffffff9a53d075>] dump_stack+0x68/0xa3 [87487.342198] [<ffffffff99e119a1>] ? console_unlock+0x281/0x6d0 [87487.345364] [<ffffffff99d6b91f>] __warn+0xff/0x140 [87487.348513] [<ffffffff99d6b9aa>] warn_slowpath_fmt+0x4a/0x50 [87487.351659] [<ffffffff9a58b5de>] __list_add+0xae/0x130 [87487.354772] [<ffffffff9add5094>] ? _raw_spin_lock+0x64/0x70 [87487.357915] [<ffffffff99eefd66>] padata_reorder+0x1e6/0x420 [87487.361084] [<ffffffff99ef0055>] padata_do_serial+0xa5/0x120 padata_reorder calls list_add_tail with the list to which its adding locked, which seems correct: spin_lock(&squeue->serial.lock); list_add_tail(&padata->list, &squeue->serial.list); spin_unlock(&squeue->serial.lock); This therefore leaves only place where such inconsistency could occur: if padata->list is added at the same time on two different threads. This pdata pointer comes from the function call to padata_get_next(pd), which has in it the following block: next_queue = per_cpu_ptr(pd->pqueue, cpu); padata = NULL; reorder = &next_queue->reorder; if (!list_empty(&reorder->list)) { padata = list_entry(reorder->list.next, struct padata_priv, list); spin_lock(&reorder->lock); list_del_init(&padata->list); atomic_dec(&pd->reorder_objects); spin_unlock(&reorder->lock); pd->processed++; goto out; } out: return padata; I strongly suspect that the problem here is that two threads can race on reorder list. Even though the deletion is locked, call to list_entry is not locked, which means it's feasible that two threads pick up the same padata object and subsequently call list_add_tail on them at the same time. The fix is thus be hoist that lock outside of that block. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Acked-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-15fgraph: Handle a case where a tracer ignores set_graph_notraceSteven Rostedt (Red Hat)
[ Upstream commit 794de08a16cf1fc1bf785dc48f66d36218cf6d88 ] Both the wakeup and irqsoff tracers can use the function graph tracer when the display-graph option is set. The problem is that they ignore the notrace file, and record the entry of functions that would be ignored by the function_graph tracer. This causes the trace->depth to be recorded into the ring buffer. The set_graph_notrace uses a trick by adding a large negative number to the trace->depth when a graph function is to be ignored. On trace output, the graph function uses the depth to record a stack of functions. But since the depth is negative, it accesses the array with a negative number and causes an out of bounds access that can cause a kernel oops or corrupt data. Have the print functions handle cases where a tracer still records functions even when they are in set_graph_notrace. Also add warnings if the depth is below zero before accessing the array. Note, the function graph logic will still prevent the return of these functions from being recorded, which means that they will be left hanging without a return. For example: # echo '*spin*' > set_graph_notrace # echo 1 > options/display-graph # echo wakeup > current_tracer # cat trace [...] _raw_spin_lock() { preempt_count_add() { do_raw_spin_lock() { update_rq_clock(); Where it should look like: _raw_spin_lock() { preempt_count_add(); do_raw_spin_lock(); } update_rq_clock(); Cc: stable@vger.kernel.org Cc: Namhyung Kim <namhyung.kim@lge.com> Fixes: 29ad23b00474 ("ftrace: Add set_graph_notrace filter") Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-12-23cpuset: handle race between CPU hotplug and cpuset_hotplug_workJoonwoo Park
[ Upstream commit 28b89b9e6f7b6c8fef7b3af39828722bca20cfee ] A discrepancy between cpu_online_mask and cpuset's effective_cpus mask is inevitable during hotplug since cpuset defers updating of effective_cpus mask using a workqueue, during which time nothing prevents the system from more hotplug operations. For that reason guarantee_online_cpus() walks up the cpuset hierarchy until it finds an intersection under the assumption that top cpuset's effective_cpus mask intersects with cpu_online_mask even with such a race occurring. However a sequence of CPU hotplugs can open a time window, during which none of the effective CPUs in the top cpuset intersect with cpu_online_mask. For example when there are 4 possible CPUs 0-3 and only CPU0 is online: ======================== =========================== cpu_online_mask top_cpuset.effective_cpus ======================== =========================== echo 1 > cpu2/online. CPU hotplug notifier woke up hotplug work but not yet scheduled. [0,2] [0] echo 0 > cpu0/online. The workqueue is still runnable. [2] [0] ======================== =========================== Now there is no intersection between cpu_online_mask and top_cpuset.effective_cpus. Thus invoking sys_sched_setaffinity() at this moment can cause following: Unable to handle kernel NULL pointer dereference at virtual address 000000d0 ------------[ cut here ]------------ Kernel BUG at ffffffc0001389b0 [verbose debug info unavailable] Internal error: Oops - BUG: 96000005 [#1] PREEMPT SMP Modules linked in: CPU: 2 PID: 1420 Comm: taskset Tainted: G W 4.4.8+ #98 task: ffffffc06a5c4880 ti: ffffffc06e124000 task.ti: ffffffc06e124000 PC is at guarantee_online_cpus+0x2c/0x58 LR is at cpuset_cpus_allowed+0x4c/0x6c <snip> Process taskset (pid: 1420, stack limit = 0xffffffc06e124020) Call trace: [<ffffffc0001389b0>] guarantee_online_cpus+0x2c/0x58 [<ffffffc00013b208>] cpuset_cpus_allowed+0x4c/0x6c [<ffffffc0000d61f0>] sched_setaffinity+0xc0/0x1ac [<ffffffc0000d6374>] SyS_sched_setaffinity+0x98/0xac [<ffffffc000085cb0>] el0_svc_naked+0x24/0x28 The top cpuset's effective_cpus are guaranteed to be identical to cpu_online_mask eventually. Hence fall back to cpu_online_mask when there is no intersection between top cpuset's effective_cpus and cpu_online_mask. Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Tejun Heo <tj@kernel.org> Cc: cgroups@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: <stable@vger.kernel.org> # 3.17+ Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-10-05genirq: Generic chip: Change irq_reg_{readl,writel} argumentsKevin Cernekee
[ Upstream commit 332fd7c4fef5f3b166e93decb07fd69eb24f7998 ] Pass in the irq_chip_generic struct so we can use different readl/writel settings for each irqchip driver, when appropriate. Compute (gc->reg_base + reg_offset) in the helper function because this is pretty much what all callers want to do anyway. Compile-tested using the following configurations: at91_dt_defconfig (CONFIG_ATMEL_AIC_IRQ=y) sama5_defconfig (CONFIG_ATMEL_AIC5_IRQ=y) sunxi_defconfig (CONFIG_ARCH_SUNXI=y) tb10x (ARC) is untested. Signed-off-by: Kevin Cernekee <cernekee@gmail.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Acked-by: Arnd Bergmann <arnd@arndb.de> Link: https://lkml.kernel.org/r/1415342669-30640-3-git-send-email-cernekee@gmail.com Signed-off-by: Jason Cooper <jason@lakedaemon.net> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-10-05sched/core: Fix a race between try_to_wake_up() and a woken up taskBalbir Singh
[ Upstream commit 135e8c9250dd5c8c9aae5984fde6f230d0cbfeaf ] The origin of the issue I've seen is related to a missing memory barrier between check for task->state and the check for task->on_rq. The task being woken up is already awake from a schedule() and is doing the following: do { schedule() set_current_state(TASK_(UN)INTERRUPTIBLE); } while (!cond); The waker, actually gets stuck doing the following in try_to_wake_up(): while (p->on_cpu) cpu_relax(); Analysis: The instance I've seen involves the following race: CPU1 CPU2 while () { if (cond) break; do { schedule(); set_current_state(TASK_UN..) } while (!cond); wakeup_routine() spin_lock_irqsave(wait_lock) raw_spin_lock_irqsave(wait_lock) wake_up_process() } try_to_wake_up() set_current_state(TASK_RUNNING); .. list_del(&waiter.list); CPU2 wakes up CPU1, but before it can get the wait_lock and set current state to TASK_RUNNING the following occurs: CPU3 wakeup_routine() raw_spin_lock_irqsave(wait_lock) if (!list_empty) wake_up_process() try_to_wake_up() raw_spin_lock_irqsave(p->pi_lock) .. if (p->on_rq && ttwu_wakeup()) .. while (p->on_cpu) cpu_relax() .. CPU3 tries to wake up the task on CPU1 again since it finds it on the wait_queue, CPU1 is spinning on wait_lock, but immediately after CPU2, CPU3 got it. CPU3 checks the state of p on CPU1, it is TASK_UNINTERRUPTIBLE and the task is spinning on the wait_lock. Interestingly since p->on_rq is checked under pi_lock, I've noticed that try_to_wake_up() finds p->on_rq to be 0. This was the most confusing bit of the analysis, but p->on_rq is changed under runqueue lock, rq_lock, the p->on_rq check is not reliable without this fix IMHO. The race is visible (based on the analysis) only when ttwu_queue() does a remote wakeup via ttwu_queue_remote. In which case the p->on_rq change is not done uder the pi_lock. The result is that after a while the entire system locks up on the raw_spin_irqlock_save(wait_lock) and the holder spins infintely Reproduction of the issue: The issue can be reproduced after a long run on my system with 80 threads and having to tweak available memory to very low and running memory stress-ng mmapfork test. It usually takes a long time to reproduce. I am trying to work on a test case that can reproduce the issue faster, but thats work in progress. I am still testing the changes on my still in a loop and the tests seem OK thus far. Big thanks to Benjamin and Nick for helping debug this as well. Ben helped catch the missing barrier, Nick caught every missing bit in my theory. Signed-off-by: Balbir Singh <bsingharora@gmail.com> [ Updated comment to clarify matching barriers. Many architectures do not have a full barrier in switch_to() so that cannot be relied upon. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Alexey Kardashevskiy <aik@ozlabs.ru> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <nicholas.piggin@gmail.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/e02cce7b-d9ca-1ad0-7a61-ea97c7582b37@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-09-12cpuset: make sure new tasks conform to the current config of the cpusetZefan Li
[ Upstream commit 06f4e94898918bcad00cdd4d349313a439d6911e ] A new task inherits cpus_allowed and mems_allowed masks from its parent, but if someone changes cpuset's config by writing to cpuset.cpus/cpuset.mems before this new task is inserted into the cgroup's task list, the new task won't be updated accordingly. Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-08-31timekeeping: Cap array access in timekeeping_debugJohn Stultz
[ Upstream commit a4f8f6667f099036c88f231dcad4cf233652c824 ] It was reported that hibernation could fail on the 2nd attempt, where the system hangs at hibernate() -> syscore_resume() -> i8237A_resume() -> claim_dma_lock(), because the lock has already been taken. However there is actually no other process would like to grab this lock on that problematic platform. Further investigation showed that the problem is triggered by setting /sys/power/pm_trace to 1 before the 1st hibernation. Since once pm_trace is enabled, the rtc becomes unmeaningful after suspend, and meanwhile some BIOSes would like to adjust the 'invalid' RTC (e.g, smaller than 1970) to the release date of that motherboard during POST stage, thus after resumed, it may seem that the system had a significant long sleep time which is a completely meaningless value. Then in timekeeping_resume -> tk_debug_account_sleep_time, if the bit31 of the sleep time happened to be set to 1, fls() returns 32 and we add 1 to sleep_time_bin[32], which causes an out of bounds array access and therefor memory being overwritten. As depicted by System.map: 0xffffffff81c9d080 b sleep_time_bin 0xffffffff81c9d100 B dma_spin_lock the dma_spin_lock.val is set to 1, which caused this problem. This patch adds a sanity check in tk_debug_account_sleep_time() to ensure we don't index past the sleep_time_bin array. [jstultz: Problem diagnosed and original patch by Chen Yu, I've solved the issue slightly differently, but borrowed his excelent explanation of the issue here.] Fixes: 5c83545f24ab "power: Add option to log time spent in suspend" Reported-by: Janek Kozicki <cosurgi@gmail.com> Reported-by: Chen Yu <yu.c.chen@intel.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: linux-pm@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Xunlei Pang <xpang@redhat.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: stable <stable@vger.kernel.org> Cc: Zhang Rui <rui.zhang@intel.com> Link: http://lkml.kernel.org/r/1471993702-29148-3-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-08-31uprobes: Fix the memcg accountingOleg Nesterov
[ Upstream commit 6c4687cc17a788a6dd8de3e27dbeabb7cbd3e066 ] __replace_page() wronlgy calls mem_cgroup_cancel_charge() in "success" path, it should only do this if page_check_address() fails. This means that every enable/disable leads to unbalanced mem_cgroup_uncharge() from put_page(old_page), it is trivial to underflow the page_counter->count and trigger OOM. Reported-and-tested-by: Brenden Blanco <bblanco@plumgrid.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: stable@vger.kernel.org # 3.17+ Fixes: 00501b531c47 ("mm: memcontrol: rewrite charge API") Link: http://lkml.kernel.org/r/20160817153629.GB29724@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-08-22module: Invalidate signatures on force-loaded modulesBen Hutchings
[ Upstream commit bca014caaa6130e57f69b5bf527967aa8ee70fdd ] Signing a module should only make it trusted by the specific kernel it was built for, not anything else. Loading a signed module meant for a kernel with a different ABI could have interesting effects. Therefore, treat all signatures as invalid when a module is force-loaded. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: stable@vger.kernel.org Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-08-22audit: fix a double fetch in audit_log_single_execve_arg()Paul Moore
[ Upstream commit 43761473c254b45883a64441dd0bc85a42f3645c ] There is a double fetch problem in audit_log_single_execve_arg() where we first check the execve(2) argumnets for any "bad" characters which would require hex encoding and then re-fetch the arguments for logging in the audit record[1]. Of course this leaves a window of opportunity for an unsavory application to munge with the data. This patch reworks things by only fetching the argument data once[2] into a buffer where it is scanned and logged into the audit records(s). In addition to fixing the double fetch, this patch improves on the original code in a few other ways: better handling of large arguments which require encoding, stricter record length checking, and some performance improvements (completely unverified, but we got rid of some strlen() calls, that's got to be a good thing). As part of the development of this patch, I've also created a basic regression test for the audit-testsuite, the test can be tracked on GitHub at the following link: * https://github.com/linux-audit/audit-testsuite/issues/25 [1] If you pay careful attention, there is actually a triple fetch problem due to a strnlen_user() call at the top of the function. [2] This is a tiny white lie, we do make a call to strnlen_user() prior to fetching the argument data. I don't like it, but due to the way the audit record is structured we really have no choice unless we copy the entire argument at once (which would require a rather wasteful allocation). The good news is that with this patch the kernel no longer relies on this strnlen_user() value for anything beyond recording it in the log, we also update it with a trustworthy value whenever possible. Reported-by: Pengfei Wang <wpengfeinudt@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-08-22Fix broken audit tests for exec arg lenLinus Torvalds
[ Upstream commit 45820c294fe1b1a9df495d57f40585ef2d069a39 ] The "fix" in commit 0b08c5e5944 ("audit: Fix check of return value of strnlen_user()") didn't fix anything, it broke things. As reported by Steven Rostedt: "Yes, strnlen_user() returns 0 on fault, but if you look at what len is set to, than you would notice that on fault len would be -1" because we just subtracted one from the return value. So testing against 0 doesn't test for a fault condition, it tests against a perfectly valid empty string. Also fix up the usual braindamage wrt using WARN_ON() inside a conditional - make it part of the conditional and remove the explicit unlikely() (which is already part of the WARN_ON*() logic, exactly so that you don't have to write unreadable code. Reported-and-tested-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Cc: Paul Moore <pmoore@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-08-22audit: Fix check of return value of strnlen_user()Jan Kara
[ Upstream commit 0b08c5e59441d08ab4b5e72afefd5cd98a4d83df ] strnlen_user() returns 0 when it hits fault, not -1. Fix the test in audit_log_single_execve_arg(). Luckily this shouldn't ever happen unless there's a kernel bug so it's mostly a cosmetic fix. CC: Paul Moore <pmoore@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Paul Moore <pmoore@redhat.com> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-08-07posix_cpu_timer: Exit early when process has been reapedAlexey Dobriyan
[ Upstream commit 2c13ce8f6b2f6fd9ba2f9261b1939fc0f62d1307 ] Variable "now" seems to be genuinely used unintialized if branch if (CPUCLOCK_PERTHREAD(timer->it_clock)) { is not taken and branch if (unlikely(sighand == NULL)) { is taken. In this case the process has been reaped and the timer is marked as disarmed anyway. So none of the postprocessing of the sample is required. Return right away. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20160707223911.GA26483@p183.telecom.by Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-07-12pipe: limit the per-user amount of pages allocated in pipesWilly Tarreau
[ Upstream commit 759c01142a5d0f364a462346168a56de28a80f52 ] On no-so-small systems, it is possible for a single process to cause an OOM condition by filling large pipes with data that are never read. A typical process filling 4000 pipes with 1 MB of data will use 4 GB of memory. On small systems it may be tricky to set the pipe max size to prevent this from happening. This patch makes it possible to enforce a per-user soft limit above which new pipes will be limited to a single page, effectively limiting them to 4 kB each, as well as a hard limit above which no new pipes may be created for this user. This has the effect of protecting the system against memory abuse without hurting other users, and still allowing pipes to work correctly though with less data at once. The limit are controlled by two new sysctls : pipe-user-pages-soft, and pipe-user-pages-hard. Both may be disabled by setting them to zero. The default soft limit allows the default number of FDs per process (1024) to create pipes of the default size (64kB), thus reaching a limit of 64MB before starting to create only smaller pipes. With 256 processes limited to 1024 FDs each, this results in 1024*64kB + (256*1024 - 1024) * 4kB = 1084 MB of memory allocated for a user. The hard limit is disabled by default to avoid breaking existing applications that make intensive use of pipes (eg: for splicing). Reported-by: socketpair@gmail.com Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Mitigates: CVE-2013-4312 (Linux 2.0+) Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2016-07-12bpf: fix double-fdput in replace_map_fd_with_map_ptr()Jann Horn
[ Upstream commit 8358b02bf67d3a5d8a825070e1aa73f25fb2e4c7 ] When bpf(BPF_PROG_LOAD, ...) was invoked with a BPF program whose bytecode references a non-map file descriptor as a map file descriptor, the error handling code called fdput() twice instead of once (in __bpf_map_get() and in replace_map_fd_with_map_ptr()). If the file descriptor table of the current task is shared, this causes f_count to be decremented too much, allowing the struct file to be freed while it is still in use (use-after-free). This can be exploited to gain root privileges by an unprivileged user. This bug was introduced in commit 0246e64d9a5f ("bpf: handle pseudo BPF_LD_IMM64 insn"), but is only exploitable since commit 1be7f75d1668 ("bpf: enable non-root eBPF programs") because previously, CAP_SYS_ADMIN was required to reach the vulnerable code. (posted publicly according to request by maintainer) Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2016-07-12futex: Acknowledge a new waiter in counter before plistDavidlohr Bueso
[ Upstream commit fe1bce9e2107ba3a8faffe572483b6974201a0e6 ] Otherwise an incoming waker on the dest hash bucket can miss the waiter adding itself to the plist during the lockless check optimization (small window but still the correct way of doing this); similarly to the decrement counterpart. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: bigeasy@linutronix.de Cc: dvhart@infradead.org Cc: stable@kernel.org Link: http://lkml.kernel.org/r/1461208164-29150-1-git-send-email-dave@stgolabs.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2016-07-12tracing: Handle NULL formats in hold_module_trace_bprintk_format()Steven Rostedt (Red Hat)
[ Upstream commit 70c8217acd4383e069fe1898bbad36ea4fcdbdcc ] If a task uses a non constant string for the format parameter in trace_printk(), then the trace_printk_fmt variable is set to NULL. This variable is then saved in the __trace_printk_fmt section. The function hold_module_trace_bprintk_format() checks to see if duplicate formats are used by modules, and reuses them if so (saves them to the list if it is new). But this function calls lookup_format() that does a strcmp() to the value (which is now NULL) and can cause a kernel oops. This wasn't an issue till 3debb0a9ddb ("tracing: Fix trace_printk() to print when not using bprintk()") which added "__used" to the trace_printk_fmt variable, and before that, the kernel simply optimized it out (no NULL value was saved). The fix is simply to handle the NULL pointer in lookup_format() and have the caller ignore the value if it was NULL. Link: http://lkml.kernel.org/r/1464769870-18344-1-git-send-email-zhengjun.xing@intel.com Reported-by: xingzhen <zhengjun.xing@intel.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Fixes: 3debb0a9ddb ("tracing: Fix trace_printk() to print when not using bprintk()") Cc: stable@vger.kernel.org # v3.5+ Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>