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2023-04-13ring-buffer: Fix race while reader and writer are on the same pageZheng Yejian1-1/+12
commit 6455b6163d8c680366663cdb8c679514d55fc30c upstream. When user reads file 'trace_pipe', kernel keeps printing following logs that warn at "cpu_buffer->reader_page->read > rb_page_size(reader)" in rb_get_reader_page(). It just looks like there's an infinite loop in tracing_read_pipe(). This problem occurs several times on arm64 platform when testing v5.10 and below. Call trace: rb_get_reader_page+0x248/0x1300 rb_buffer_peek+0x34/0x160 ring_buffer_peek+0xbc/0x224 peek_next_entry+0x98/0xbc __find_next_entry+0xc4/0x1c0 trace_find_next_entry_inc+0x30/0x94 tracing_read_pipe+0x198/0x304 vfs_read+0xb4/0x1e0 ksys_read+0x74/0x100 __arm64_sys_read+0x24/0x30 el0_svc_common.constprop.0+0x7c/0x1bc do_el0_svc+0x2c/0x94 el0_svc+0x20/0x30 el0_sync_handler+0xb0/0xb4 el0_sync+0x160/0x180 Then I dump the vmcore and look into the problematic per_cpu ring_buffer, I found that tail_page/commit_page/reader_page are on the same page while reader_page->read is obviously abnormal: tail_page == commit_page == reader_page == { .write = 0x100d20, .read = 0x8f9f4805, // Far greater than 0xd20, obviously abnormal!!! .entries = 0x10004c, .real_end = 0x0, .page = { .time_stamp = 0x857257416af0, .commit = 0xd20, // This page hasn't been full filled. // .data[0...0xd20] seems normal. } } The root cause is most likely the race that reader and writer are on the same page while reader saw an event that not fully committed by writer. To fix this, add memory barriers to make sure the reader can see the content of what is committed. Since commit a0fcaaed0c46 ("ring-buffer: Fix race between reset page and reading page") has added the read barrier in rb_get_reader_page(), here we just need to add the write barrier. Link: https://lore.kernel.org/linux-trace-kernel/20230325021247.2923907-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Fixes: 77ae365eca89 ("ring-buffer: make lockless") Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-13tracing: Free error logs of tracing instancesSteven Rostedt (Google)1-0/+1
commit 3357c6e429643231e60447b52ffbb7ac895aca22 upstream. When a tracing instance is removed, the error messages that hold errors that occurred in the instance needs to be freed. The following reports a memory leak: # cd /sys/kernel/tracing # mkdir instances/foo # echo 'hist:keys=x' > instances/foo/events/sched/sched_switch/trigger # cat instances/foo/error_log [ 117.404795] hist:sched:sched_switch: error: Couldn't find field Command: hist:keys=x ^ # rmdir instances/foo Then check for memory leaks: # echo scan > /sys/kernel/debug/kmemleak # cat /sys/kernel/debug/kmemleak unreferenced object 0xffff88810d8ec700 (size 192): comm "bash", pid 869, jiffies 4294950577 (age 215.752s) hex dump (first 32 bytes): 60 dd 68 61 81 88 ff ff 60 dd 68 61 81 88 ff ff `.ha....`.ha.... a0 30 8c 83 ff ff ff ff 26 00 0a 00 00 00 00 00 .0......&....... backtrace: [<00000000dae26536>] kmalloc_trace+0x2a/0xa0 [<00000000b2938940>] tracing_log_err+0x277/0x2e0 [<000000004a0e1b07>] parse_atom+0x966/0xb40 [<0000000023b24337>] parse_expr+0x5f3/0xdb0 [<00000000594ad074>] event_hist_trigger_parse+0x27f8/0x3560 [<00000000293a9645>] trigger_process_regex+0x135/0x1a0 [<000000005c22b4f2>] event_trigger_write+0x87/0xf0 [<000000002cadc509>] vfs_write+0x162/0x670 [<0000000059c3b9be>] ksys_write+0xca/0x170 [<00000000f1cddc00>] do_syscall_64+0x3e/0xc0 [<00000000868ac68c>] entry_SYSCALL_64_after_hwframe+0x72/0xdc unreferenced object 0xffff888170c35a00 (size 32): comm "bash", pid 869, jiffies 4294950577 (age 215.752s) hex dump (first 32 bytes): 0a 20 20 43 6f 6d 6d 61 6e 64 3a 20 68 69 73 74 . Command: hist 3a 6b 65 79 73 3d 78 0a 00 00 00 00 00 00 00 00 :keys=x......... backtrace: [<000000006a747de5>] __kmalloc+0x4d/0x160 [<000000000039df5f>] tracing_log_err+0x29b/0x2e0 [<000000004a0e1b07>] parse_atom+0x966/0xb40 [<0000000023b24337>] parse_expr+0x5f3/0xdb0 [<00000000594ad074>] event_hist_trigger_parse+0x27f8/0x3560 [<00000000293a9645>] trigger_process_regex+0x135/0x1a0 [<000000005c22b4f2>] event_trigger_write+0x87/0xf0 [<000000002cadc509>] vfs_write+0x162/0x670 [<0000000059c3b9be>] ksys_write+0xca/0x170 [<00000000f1cddc00>] do_syscall_64+0x3e/0xc0 [<00000000868ac68c>] entry_SYSCALL_64_after_hwframe+0x72/0xdc The problem is that the error log needs to be freed when the instance is removed. Link: https://lore.kernel.org/lkml/76134d9f-a5ba-6a0d-37b3-28310b4a1e91@alu.unizg.hr/ Link: https://lore.kernel.org/linux-trace-kernel/20230404194504.5790b95f@gandalf.local.home Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Thorsten Leemhuis <regressions@leemhuis.info> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Eric Biggers <ebiggers@kernel.org> Fixes: 2f754e771b1a6 ("tracing: Have the error logs show up in the proper instances") Reported-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr> Tested-by: Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-13ftrace: Fix issue that 'direct->addr' not restored in modify_ftrace_direct()Zheng Yejian1-6/+9
commit 2a2d8c51defb446e8d89a83f42f8e5cd529111e9 upstream. Syzkaller report a WARNING: "WARN_ON(!direct)" in modify_ftrace_direct(). Root cause is 'direct->addr' was changed from 'old_addr' to 'new_addr' but not restored if error happened on calling ftrace_modify_direct_caller(). Then it can no longer find 'direct' by that 'old_addr'. To fix it, restore 'direct->addr' to 'old_addr' explicitly in error path. Link: https://lore.kernel.org/linux-trace-kernel/20230330025223.1046087-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Cc: <mhiramat@kernel.org> Cc: <mark.rutland@arm.com> Cc: <ast@kernel.org> Cc: <daniel@iogearbox.net> Fixes: 8a141dd7f706 ("ftrace: Fix modify_ftrace_direct.") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-13perf/core: Fix the same task check in perf_event_set_outputKan Liang1-1/+1
[ Upstream commit 24d3ae2f37d8bc3c14b31d353c5d27baf582b6a6 ] The same task check in perf_event_set_output has some potential issues for some usages. For the current perf code, there is a problem if using of perf_event_open() to have multiple samples getting into the same mmap’d memory when they are both attached to the same process. https://lore.kernel.org/all/92645262-D319-4068-9C44-2409EF44888E@gmail.com/ Because the event->ctx is not ready when the perf_event_set_output() is invoked in the perf_event_open(). Besides the above issue, before the commit bd2756811766 ("perf: Rewrite core context handling"), perf record can errors out when sampling with a hardware event and a software event as below. $ perf record -e cycles,dummy --per-thread ls failed to mmap with 22 (Invalid argument) That's because that prior to the commit a hardware event and a software event are from different task context. The problem should be a long time issue since commit c3f00c70276d ("perk: Separate find_get_context() from event initialization"). The task struct is stored in the event->hw.target for each per-thread event. It is a more reliable way to determine whether two events are attached to the same task. The event->hw.target was also introduced several years ago by the commit 50f16a8bf9d7 ("perf: Remove type specific target pointers"). It can not only be used to fix the issue with the current code, but also back port to fix the issues with an older kernel. Note: The event->hw.target was introduced later than commit c3f00c70276d. The patch may cannot be applied between the commit c3f00c70276d and commit 50f16a8bf9d7. Anybody that wants to back-port this at that period may have to find other solutions. Fixes: c3f00c70276d ("perf: Separate find_get_context() from event initialization") Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Zhengjun Xing <zhengjun.xing@linux.intel.com> Link: https://lkml.kernel.org/r/20230322202449.512091-1-kan.liang@linux.intel.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-13bpf: hash map, avoid deadlock with suitable hash maskTonghao Zhang1-2/+2
[ Upstream commit 9f907439dc80e4a2fcfb949927b36c036468dbb3 ] The deadlock still may occur while accessed in NMI and non-NMI context. Because in NMI, we still may access the same bucket but with different map_locked index. For example, on the same CPU, .max_entries = 2, we update the hash map, with key = 4, while running bpf prog in NMI nmi_handle(), to update hash map with key = 20, so it will have the same bucket index but have different map_locked index. To fix this issue, using min mask to hash again. Fixes: 20b6cc34ea74 ("bpf: Avoid hashtab deadlock with map_locked") Signed-off-by: Tonghao Zhang <tong@infragraf.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <martin.lau@linux.dev> Cc: Song Liu <song@kernel.org> Cc: Yonghong Song <yhs@fb.com> Cc: John Fastabend <john.fastabend@gmail.com> Cc: KP Singh <kpsingh@kernel.org> Cc: Stanislav Fomichev <sdf@google.com> Cc: Hao Luo <haoluo@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Hou Tao <houtao1@huawei.com> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/20230111092903.92389-1-tong@infragraf.org Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-05tracing: Fix wrong return in kprobe_event_gen_test.cAnton Gusev1-2/+2
[ Upstream commit bc4f359b3b607daac0290d0038561237a86b38cb ] Overwriting the error code with the deletion result may cause the function to return 0 despite encountering an error. Commit b111545d26c0 ("tracing: Remove the useless value assignment in test_create_synth_event()") solves a similar issue by returning the original error code, so this patch does the same. Found by Linux Verification Center (linuxtesting.org) with SVACE. Link: https://lore.kernel.org/linux-trace-kernel/20230131075818.5322-1-aagusev@ispras.ru Signed-off-by: Anton Gusev <aagusev@ispras.ru> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-05sched_getaffinity: don't assume 'cpumask_size()' is fully initializedLinus Torvalds2-3/+3
[ Upstream commit 6015b1aca1a233379625385feb01dd014aca60b5 ] The getaffinity() system call uses 'cpumask_size()' to decide how big the CPU mask is - so far so good. It is indeed the allocation size of a cpumask. But the code also assumes that the whole allocation is initialized without actually doing so itself. That's wrong, because we might have fixed-size allocations (making copying and clearing more efficient), but not all of it is then necessarily used if 'nr_cpu_ids' is smaller. Having checked other users of 'cpumask_size()', they all seem to be ok, either using it purely for the allocation size, or explicitly zeroing the cpumask before using the size in bytes to copy it. See for example the ublk_ctrl_get_queue_affinity() function that uses the proper 'zalloc_cpumask_var()' to make sure that the whole mask is cleared, whether the storage is on the stack or if it was an external allocation. Fix this by just zeroing the allocation before using it. Do the same for the compat version of sched_getaffinity(), which had the same logic. Also, for consistency, make sched_getaffinity() use 'cpumask_bits()' to access the bits. For a cpumask_var_t, it ends up being a pointer to the same data either way, but it's just a good idea to treat it like you would a 'cpumask_t'. The compat case already did that. Reported-by: Ryan Roberts <ryan.roberts@arm.com> Link: https://lore.kernel.org/lkml/7d026744-6bd6-6827-0471-b5e8eae0be3f@arm.com/ Cc: Yury Norov <yury.norov@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-05kcsan: avoid passing -g for testMarco Elver1-1/+1
[ Upstream commit 5eb39cde1e2487ba5ec1802dc5e58a77e700d99e ] Nathan reported that when building with GNU as and a version of clang that defaults to DWARF5, the assembler will complain with: Error: non-constant .uleb128 is not supported This is because `-g` defaults to the compiler debug info default. If the assembler does not support some of the directives used, the above errors occur. To fix, remove the explicit passing of `-g`. All the test wants is that stack traces print valid function names, and debug info is not required for that. (I currently cannot recall why I added the explicit `-g`.) Link: https://lkml.kernel.org/r/20230316224705.709984-2-elver@google.com Fixes: 1fe84fd4a402 ("kcsan: Add test suite") Signed-off-by: Marco Elver <elver@google.com> Reported-by: Nathan Chancellor <nathan@kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-05kernel: kcsan: kcsan_test: build without structleak pluginAnders Roxell1-0/+1
[ Upstream commit 6fcd4267a840d0536b8e5334ad5f31e4105fce85 ] Building kcsan_test with structleak plugin enabled makes the stack frame size to grow. kernel/kcsan/kcsan_test.c:704:1: error: the frame size of 3296 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] Turn off the structleak plugin checks for kcsan_test. Link: https://lkml.kernel.org/r/20221128104358.2660634-1-anders.roxell@linaro.org Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Suggested-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Marco Elver <elver@google.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: David Gow <davidgow@google.com> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Stable-dep-of: 5eb39cde1e24 ("kcsan: avoid passing -g for test") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-30sched/fair: Sanitize vruntime of entity being migratedVincent Guittot2-11/+47
commit a53ce18cacb477dd0513c607f187d16f0fa96f71 upstream. Commit 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed") fixes an overflowing bug, but ignore a case that se->exec_start is reset after a migration. For fixing this case, we delay the reset of se->exec_start after placing the entity which se->exec_start to detect long sleeping task. In order to take into account a possible divergence between the clock_task of 2 rqs, we increase the threshold to around 104 days. Fixes: 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed") Originally-by: Zhang Qiao <zhangqiao22@huawei.com> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Zhang Qiao <zhangqiao22@huawei.com> Link: https://lore.kernel.org/r/20230317160810.107988-1-vincent.guittot@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-30sched/fair: sanitize vruntime of entity being placedZhang Qiao1-2/+13
commit 829c1651e9c4a6f78398d3e67651cef9bb6b42cc upstream. When a scheduling entity is placed onto cfs_rq, its vruntime is pulled to the base level (around cfs_rq->min_vruntime), so that the entity doesn't gain extra boost when placed backwards. However, if the entity being placed wasn't executed for a long time, its vruntime may get too far behind (e.g. while cfs_rq was executing a low-weight hog), which can inverse the vruntime comparison due to s64 overflow. This results in the entity being placed with its original vruntime way forwards, so that it will effectively never get to the cpu. To prevent that, ignore the vruntime of the entity being placed if it didn't execute for much longer than the characteristic sheduler time scale. [rkagan: formatted, adjusted commit log, comments, cutoff value] Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com> Co-developed-by: Roman Kagan <rkagan@amazon.de> Signed-off-by: Roman Kagan <rkagan@amazon.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20230130122216.3555094-1-rkagan@amazon.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-30entry/rcu: Check TIF_RESCHED _after_ delayed RCU wake-upFrederic Weisbecker1-1/+2
[ Upstream commit b416514054810cf2d2cc348ae477cea619b64da7 ] RCU sometimes needs to perform a delayed wake up for specific kthreads handling offloaded callbacks (RCU_NOCB). These wakeups are performed by timers and upon entry to idle (also to guest and to user on nohz_full). However the delayed wake-up on kernel exit is actually performed after the thread flags are fetched towards the fast path check for work to do on exit to user. As a result, and if there is no other pending work to do upon that kernel exit, the current task will resume to userspace with TIF_RESCHED set and the pending wake up ignored. Fix this with fetching the thread flags _after_ the delayed RCU-nocb kthread wake-up. Fixes: 47b8ff194c1f ("entry: Explicitly flush pending rcuog wakeup before last rescheduling point") Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230315194349.10798-3-joel@joelfernandes.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-30entry: Snapshot thread flagsMark Rutland2-4/+4
[ Upstream commit 6ce895128b3bff738fe8d9dd74747a03e319e466 ] Some thread flags can be set remotely, and so even when IRQs are disabled, the flags can change under our feet. Generally this is unlikely to cause a problem in practice, but it is somewhat unsound, and KCSAN will legitimately warn that there is a data race. To avoid such issues, a snapshot of the flags has to be taken prior to using them. Some places already use READ_ONCE() for that, others do not. Convert them all to the new flag accessor helpers. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/r/20211129130653.2037928-3-mark.rutland@arm.com Stable-dep-of: b41651405481 ("entry/rcu: Check TIF_RESCHED _after_ delayed RCU wake-up") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-30bpf: Adjust insufficient default bpf_jit_limitDaniel Borkmann1-1/+1
[ Upstream commit 10ec8ca8ec1a2f04c4ed90897225231c58c124a7 ] We've seen recent AWS EKS (Kubernetes) user reports like the following: After upgrading EKS nodes from v20230203 to v20230217 on our 1.24 EKS clusters after a few days a number of the nodes have containers stuck in ContainerCreating state or liveness/readiness probes reporting the following error: Readiness probe errored: rpc error: code = Unknown desc = failed to exec in container: failed to start exec "4a11039f730203ffc003b7[...]": OCI runtime exec failed: exec failed: unable to start container process: unable to init seccomp: error loading seccomp filter into kernel: error loading seccomp filter: errno 524: unknown However, we had not been seeing this issue on previous AMIs and it only started to occur on v20230217 (following the upgrade from kernel 5.4 to 5.10) with no other changes to the underlying cluster or workloads. We tried the suggestions from that issue (sysctl net.core.bpf_jit_limit=452534528) which helped to immediately allow containers to be created and probes to execute but after approximately a day the issue returned and the value returned by cat /proc/vmallocinfo | grep bpf_jit | awk '{s+=$2} END {print s}' was steadily increasing. I tested bpf tree to observe bpf_jit_charge_modmem, bpf_jit_uncharge_modmem their sizes passed in as well as bpf_jit_current under tcpdump BPF filter, seccomp BPF and native (e)BPF programs, and the behavior all looks sane and expected, that is nothing "leaking" from an upstream perspective. The bpf_jit_limit knob was originally added in order to avoid a situation where unprivileged applications loading BPF programs (e.g. seccomp BPF policies) consuming all the module memory space via BPF JIT such that loading of kernel modules would be prevented. The default limit was defined back in 2018 and while good enough back then, we are generally seeing far more BPF consumers today. Adjust the limit for the BPF JIT pool from originally 1/4 to now 1/2 of the module memory space to better reflect today's needs and avoid more users running into potentially hard to debug issues. Fixes: fdadd04931c2 ("bpf: fix bpf_jit_limit knob for PAGE_SIZE >= 64K") Reported-by: Stephen Haynes <sh@synk.net> Reported-by: Lefteris Alexakis <lefteris.alexakis@kpn.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://github.com/awslabs/amazon-eks-ami/issues/1179 Link: https://github.com/awslabs/amazon-eks-ami/issues/1219 Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://lore.kernel.org/r/20230320143725.8394-1-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-30trace/hwlat: Do not start per-cpu thread if it is already runningTero Kristo1-0/+4
[ Upstream commit 08697bca9bbba15f2058fdbd9f970bd5f6a8a2e8 ] The hwlatd tracer will end up starting multiple per-cpu threads with the following script: #!/bin/sh cd /sys/kernel/debug/tracing echo 0 > tracing_on echo hwlat > current_tracer echo per-cpu > hwlat_detector/mode echo 100000 > hwlat_detector/width echo 200000 > hwlat_detector/window echo 1 > tracing_on To fix the issue, check if the hwlatd thread for the cpu is already running, before starting a new one. Along with the previous patch, this avoids running multiple instances of the same CPU thread on the system. Link: https://lore.kernel.org/all/20230302113654.2984709-1-tero.kristo@linux.intel.com/ Link: https://lkml.kernel.org/r/20230310100451.3948583-3-tero.kristo@linux.intel.com Cc: stable@vger.kernel.org Fixes: f46b16520a087 ("trace/hwlat: Implement the per-cpu mode") Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com> Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-30trace/hwlat: make use of the helper function kthread_run_on_cpu()Cai Huoqing1-5/+1
[ Upstream commit ff78f6679d2e223e073fcbdc8f70b6bc0abadf99 ] Replace kthread_create_on_cpu/wake_up_process() with kthread_run_on_cpu() to simplify the code. Link: https://lkml.kernel.org/r/20211022025711.3673-7-caihuoqing@baidu.com Signed-off-by: Cai Huoqing <caihuoqing@baidu.com> Cc: Bernard Metzler <bmt@zurich.ibm.com> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Doug Ledford <dledford@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: "Paul E . McKenney" <paulmck@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Stable-dep-of: 08697bca9bbb ("trace/hwlat: Do not start per-cpu thread if it is already running") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-30kthread: add the helper function kthread_run_on_cpu()Cai Huoqing1-0/+1
[ Upstream commit 800977f6f32e452cba6b04ef21d2f5383ca29209 ] Add a new helper function kthread_run_on_cpu(), which includes kthread_create_on_cpu/wake_up_process(). In some cases, use kthread_run_on_cpu() directly instead of kthread_create_on_node/kthread_bind/wake_up_process() or kthread_create_on_cpu/wake_up_process() or kthreadd_create/kthread_bind/wake_up_process() to simplify the code. [akpm@linux-foundation.org: export kthread_create_on_cpu to modules] Link: https://lkml.kernel.org/r/20211022025711.3673-2-caihuoqing@baidu.com Signed-off-by: Cai Huoqing <caihuoqing@baidu.com> Cc: Bernard Metzler <bmt@zurich.ibm.com> Cc: Cai Huoqing <caihuoqing@baidu.com> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Doug Ledford <dledford@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: "Paul E . McKenney" <paulmck@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Stable-dep-of: 08697bca9bbb ("trace/hwlat: Do not start per-cpu thread if it is already running") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-30tracing/hwlat: Replace sched_setaffinity with set_cpus_allowed_ptrCosta Shulyupin1-2/+2
[ Upstream commit 71c7a30442b724717a30d5e7d1662ba4904eb3d4 ] There is a problem with the behavior of hwlat in a container, resulting in incorrect output. A warning message is generated: "cpumask changed while in round-robin mode, switching to mode none", and the tracing_cpumask is ignored. This issue arises because the kernel thread, hwlatd, is not a part of the container, and the function sched_setaffinity is unable to locate it using its PID. Additionally, the task_struct of hwlatd is already known. Ultimately, the function set_cpus_allowed_ptr achieves the same outcome as sched_setaffinity, but employs task_struct instead of PID. Test case: # cd /sys/kernel/tracing # echo 0 > tracing_on # echo round-robin > hwlat_detector/mode # echo hwlat > current_tracer # unshare --fork --pid bash -c 'echo 1 > tracing_on' # dmesg -c Actual behavior: [573502.809060] hwlat_detector: cpumask changed while in round-robin mode, switching to mode none Link: https://lore.kernel.org/linux-trace-kernel/20230316144535.1004952-1-costa.shul@redhat.com Cc: Masami Hiramatsu <mhiramat@kernel.org> Fixes: 0330f7aa8ee63 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs") Signed-off-by: Costa Shulyupin <costa.shul@redhat.com> Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-30perf: fix perf_event_context->timeSong Liu1-1/+1
[ Upstream commit baf1b12a67f5b24f395baca03e442ce27cab0c18 ] Time readers rely on perf_event_context->[time|timestamp|timeoffset] to get accurate time_enabled and time_running for an event. The difference between ctx->timestamp and ctx->time is the among of time when the context is not enabled. __update_context_time(ctx, false) is used to increase timestamp, but not time. Therefore, it should only be called in ctx_sched_in() when EVENT_TIME was not enabled. Fixes: 09f5e7dc7ad7 ("perf: Fix perf_event_read_local() time") Signed-off-by: Song Liu <song@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/r/20230313171608.298734-1-song@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-30perf/core: Fix perf_output_begin parameter is incorrectly invoked in ↵Yang Jihong1-1/+1
perf_event_bpf_output [ Upstream commit eb81a2ed4f52be831c9fb879752d89645a312c13 ] syzkaller reportes a KASAN issue with stack-out-of-bounds. The call trace is as follows: dump_stack+0x9c/0xd3 print_address_description.constprop.0+0x19/0x170 __kasan_report.cold+0x6c/0x84 kasan_report+0x3a/0x50 __perf_event_header__init_id+0x34/0x290 perf_event_header__init_id+0x48/0x60 perf_output_begin+0x4a4/0x560 perf_event_bpf_output+0x161/0x1e0 perf_iterate_sb_cpu+0x29e/0x340 perf_iterate_sb+0x4c/0xc0 perf_event_bpf_event+0x194/0x2c0 __bpf_prog_put.constprop.0+0x55/0xf0 __cls_bpf_delete_prog+0xea/0x120 [cls_bpf] cls_bpf_delete_prog_work+0x1c/0x30 [cls_bpf] process_one_work+0x3c2/0x730 worker_thread+0x93/0x650 kthread+0x1b8/0x210 ret_from_fork+0x1f/0x30 commit 267fb27352b6 ("perf: Reduce stack usage of perf_output_begin()") use on-stack struct perf_sample_data of the caller function. However, perf_event_bpf_output uses incorrect parameter to convert small-sized data (struct perf_bpf_event) into large-sized data (struct perf_sample_data), which causes memory overwriting occurs in __perf_event_header__init_id. Fixes: 267fb27352b6 ("perf: Reduce stack usage of perf_output_begin()") Signed-off-by: Yang Jihong <yangjihong1@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20230314044735.56551-1-yangjihong1@huawei.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-22perf: Fix check before add_event_to_groups() in perf_group_detach()Budimir Markovic1-1/+1
commit fd0815f632c24878e325821943edccc7fde947a2 upstream. Events should only be added to a groups rb tree if they have not been removed from their context by list_del_event(). Since remove_on_exec made it possible to call list_del_event() on individual events before they are detached from their group, perf_group_detach() should check each sibling's attach_state before calling add_event_to_groups() on it. Fixes: 2e498d0a74e5 ("perf: Add support for event removal on exec") Signed-off-by: Budimir Markovic <markovicbudimir@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/ZBFzvQV9tEqoHEtH@gentoo Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-22trace/hwlat: Do not wipe the contents of per-cpu thread dataTero Kristo1-3/+0
commit 4c42f5f0d1dd20bddd9f940beb1e6ccad60c4498 upstream. Do not wipe the contents of the per-cpu kthread data when starting the tracer, as this will completely forget about already running instances and can later start new additional per-cpu threads. Link: https://lore.kernel.org/all/20230302113654.2984709-1-tero.kristo@linux.intel.com/ Link: https://lkml.kernel.org/r/20230310100451.3948583-2-tero.kristo@linux.intel.com Cc: stable@vger.kernel.org Fixes: f46b16520a087 ("trace/hwlat: Implement the per-cpu mode") Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com> Acked-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>
2023-03-22ftrace: Fix invalid address access in lookup_rec() when index is 0Chen Zhongjin1-1/+2
commit ee92fa443358f4fc0017c1d0d325c27b37802504 upstream. KASAN reported follow problem: BUG: KASAN: use-after-free in lookup_rec Read of size 8 at addr ffff000199270ff0 by task modprobe CPU: 2 Comm: modprobe Call trace: kasan_report __asan_load8 lookup_rec ftrace_location arch_check_ftrace_location check_kprobe_address_safe register_kprobe When checking pg->records[pg->index - 1].ip in lookup_rec(), it can get a pg which is newly added to ftrace_pages_start in ftrace_process_locs(). Before the first pg->index++, index is 0 and accessing pg->records[-1].ip will cause this problem. Don't check the ip when pg->index is 0. Link: https://lore.kernel.org/linux-trace-kernel/20230309080230.36064-1-chenzhongjin@huawei.com Cc: stable@vger.kernel.org Fixes: 9644302e3315 ("ftrace: Speed up search by skipping pages by address") Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-22tracing: Check field value in hist_field_name()Steven Rostedt (Google)1-0/+3
commit 9f116f76fa8c04c81aef33ad870dbf9a158e5b70 upstream. The function hist_field_name() cannot handle being passed a NULL field parameter. It should never be NULL, but due to a previous bug, NULL was passed to the function and the kernel crashed due to a NULL dereference. Mark Rutland reported this to me on IRC. The bug was fixed, but to prevent future bugs from crashing the kernel, check the field and add a WARN_ON() if it is NULL. Link: https://lkml.kernel.org/r/20230302020810.762384440@goodmis.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Reported-by: Mark Rutland <mark.rutland@arm.com> Fixes: c6afad49d127f ("tracing: Add hist trigger 'sym' and 'sym-offset' modifiers") Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-22tracing: Make splice_read available againSung-hun Kim1-0/+2
commit e400be674a1a40e9dcb2e95f84d6c1fd2d88f31d upstream. Since the commit 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops") is applied to the kernel, splice() and sendfile() calls on the trace file (/sys/kernel/debug/tracing /trace) return EINVAL. This patch restores these system calls by initializing splice_read in file_operations of the trace file. This patch only enables such functionalities for the read case. Link: https://lore.kernel.org/linux-trace-kernel/20230314013707.28814-1-sfoon.kim@samsung.com Cc: stable@vger.kernel.org Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops") Signed-off-by: Sung-hun Kim <sfoon.kim@samsung.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-17watch_queue: fix IOC_WATCH_QUEUE_SET_SIZE alloc error pathsDavid Disseldorp1-0/+1
[ Upstream commit 03e1d60e177eedbd302b77af4ea5e21b5a7ade31 ] The watch_queue_set_size() allocation error paths return the ret value set via the prior pipe_resize_ring() call, which will always be zero. As a result, IOC_WATCH_QUEUE_SET_SIZE callers such as "keyctl watch" fail to detect kernel wqueue->notes allocation failures and proceed to KEYCTL_WATCH_KEY, with any notifications subsequently lost. Fixes: c73be61cede58 ("pipe: Add general notification queue support") Signed-off-by: David Disseldorp <ddiss@suse.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-17irqdomain: Fix mapping-creation raceJohan Hovold1-18/+46
[ Upstream commit 601363cc08da25747feb87c55573dd54de91d66a ] Parallel probing of devices that share interrupts (e.g. when a driver uses asynchronous probing) can currently result in two mappings for the same hardware interrupt to be created due to missing serialisation. Make sure to hold the irq_domain_mutex when creating mappings so that looking for an existing mapping before creating a new one is done atomically. Fixes: 765230b5f084 ("driver-core: add asynchronous probing support for drivers") Fixes: b62b2cf5759b ("irqdomain: Fix handling of type settings for existing mappings") Link: https://lore.kernel.org/r/YuJXMHoT4ijUxnRb@hovoldconsulting.com Cc: stable@vger.kernel.org # 4.8 Cc: Dmitry Torokhov <dtor@chromium.org> Cc: Jon Hunter <jonathanh@nvidia.com> Tested-by: Hsin-Yi Wang <hsinyi@chromium.org> Tested-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com> Signed-off-by: Johan Hovold <johan+linaro@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230213104302.17307-7-johan+linaro@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-17btf: fix resolving BTF_KIND_VAR after ARRAY, STRUCT, UNION, PTRLorenz Bauer1-0/+1
[ Upstream commit 9b459804ff9973e173fabafba2a1319f771e85fa ] btf_datasec_resolve contains a bug that causes the following BTF to fail loading: [1] DATASEC a size=2 vlen=2 type_id=4 offset=0 size=1 type_id=7 offset=1 size=1 [2] INT (anon) size=1 bits_offset=0 nr_bits=8 encoding=(none) [3] PTR (anon) type_id=2 [4] VAR a type_id=3 linkage=0 [5] INT (anon) size=1 bits_offset=0 nr_bits=8 encoding=(none) [6] TYPEDEF td type_id=5 [7] VAR b type_id=6 linkage=0 This error message is printed during btf_check_all_types: [1] DATASEC a size=2 vlen=2 type_id=7 offset=1 size=1 Invalid type By tracing btf_*_resolve we can pinpoint the problem: btf_datasec_resolve(depth: 1, type_id: 1, mode: RESOLVE_TBD) = 0 btf_var_resolve(depth: 2, type_id: 4, mode: RESOLVE_TBD) = 0 btf_ptr_resolve(depth: 3, type_id: 3, mode: RESOLVE_PTR) = 0 btf_var_resolve(depth: 2, type_id: 4, mode: RESOLVE_PTR) = 0 btf_datasec_resolve(depth: 1, type_id: 1, mode: RESOLVE_PTR) = -22 The last invocation of btf_datasec_resolve should invoke btf_var_resolve by means of env_stack_push, instead it returns EINVAL. The reason is that env_stack_push is never executed for the second VAR. if (!env_type_is_resolve_sink(env, var_type) && !env_type_is_resolved(env, var_type_id)) { env_stack_set_next_member(env, i + 1); return env_stack_push(env, var_type, var_type_id); } env_type_is_resolve_sink() changes its behaviour based on resolve_mode. For RESOLVE_PTR, we can simplify the if condition to the following: (btf_type_is_modifier() || btf_type_is_ptr) && !env_type_is_resolved() Since we're dealing with a VAR the clause evaluates to false. This is not sufficient to trigger the bug however. The log output and EINVAL are only generated if btf_type_id_size() fails. if (!btf_type_id_size(btf, &type_id, &type_size)) { btf_verifier_log_vsi(env, v->t, vsi, "Invalid type"); return -EINVAL; } Most types are sized, so for example a VAR referring to an INT is not a problem. The bug is only triggered if a VAR points at a modifier. Since we skipped btf_var_resolve that modifier was also never resolved, which means that btf_resolved_type_id returns 0 aka VOID for the modifier. This in turn causes btf_type_id_size to return NULL, triggering EINVAL. To summarise, the following conditions are necessary: - VAR pointing at PTR, STRUCT, UNION or ARRAY - Followed by a VAR pointing at TYPEDEF, VOLATILE, CONST, RESTRICT or TYPE_TAG The fix is to reset resolve_mode to RESOLVE_TBD before attempting to resolve a VAR from a DATASEC. Fixes: 1dc92851849c ("bpf: kernel side support for BTF Var and DataSec") Signed-off-by: Lorenz Bauer <lmb@isovalent.com> Link: https://lore.kernel.org/r/20230306112138.155352-2-lmb@isovalent.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-17irqdomain: Refactor __irq_domain_alloc_irqs()Johan Hovold1-40/+48
[ Upstream commit d55f7f4c58c07beb5050a834bf57ae2ede599c7e ] Refactor __irq_domain_alloc_irqs() so that it can be called internally while holding the irq_domain_mutex. This will be used to fix a shared-interrupt mapping race, hence the Fixes tag. Fixes: b62b2cf5759b ("irqdomain: Fix handling of type settings for existing mappings") Cc: stable@vger.kernel.org # 4.8 Tested-by: Hsin-Yi Wang <hsinyi@chromium.org> Tested-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com> Signed-off-by: Johan Hovold <johan+linaro@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230213104302.17307-6-johan+linaro@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-17fork: allow CLONE_NEWTIME in clone3 flagsTobias Klauser1-1/+1
commit a402f1e35313fc7ce2ca60f543c4402c2c7c3544 upstream. Currently, calling clone3() with CLONE_NEWTIME in clone_args->flags fails with -EINVAL. This is because CLONE_NEWTIME intersects with CSIGNAL. However, CSIGNAL was deprecated when clone3 was introduced in commit 7f192e3cd316 ("fork: add clone3"), allowing re-use of that part of clone flags. Fix this by explicitly allowing CLONE_NEWTIME in clone3_args_valid. This is also in line with the respective check in check_unshare_flags which allow CLONE_NEWTIME for unshare(). Fixes: 769071ac9f20 ("ns: Introduce Time Namespace") Cc: Andrey Vagin <avagin@openvz.org> Cc: Christian Brauner <brauner@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-11kernel/fail_function: fix memory leak with using debugfs_lookup()Greg Kroah-Hartman1-4/+1
[ Upstream commit 2bb3669f576559db273efe49e0e69f82450efbca ] When calling debugfs_lookup() the result must have dput() called on it, otherwise the memory will leak over time. To make things simpler, just call debugfs_lookup_and_remove() instead which handles all of the logic at once. Cc: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Yang Yingliang <yangyingliang@huawei.com> Link: https://lore.kernel.org/r/20230202151633.2310897-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-11kernel/printk/index.c: fix memory leak with using debugfs_lookup()Greg Kroah-Hartman1-1/+1
[ Upstream commit 55bf243c514553e907efcf2bda92ba090eca8c64 ] When calling debugfs_lookup() the result must have dput() called on it, otherwise the memory will leak over time. To make things simpler, just call debugfs_lookup_and_remove() instead which handles all of the logic at once. Cc: Chris Down <chris@chrisdown.name> Cc: Petr Mladek <pmladek@suse.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: John Ogness <john.ogness@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Reviewed-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20230202151411.2308576-1-gregkh@linuxfoundation.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-11tracing: Add NULL checks for buffer in ring_buffer_free_read_page()Jia-Ju Bai1-1/+6
[ Upstream commit 3e4272b9954094907f16861199728f14002fcaf6 ] In a previous commit 7433632c9ff6, buffer, buffer->buffers and buffer->buffers[cpu] in ring_buffer_wake_waiters() can be NULL, and thus the related checks are added. However, in the same call stack, these variables are also used in ring_buffer_free_read_page(): tracing_buffers_release() ring_buffer_wake_waiters(iter->array_buffer->buffer) cpu_buffer = buffer->buffers[cpu] -> Add checks by previous commit ring_buffer_free_read_page(iter->array_buffer->buffer) cpu_buffer = buffer->buffers[cpu] -> No check Thus, to avod possible null-pointer derefernces, the related checks should be added. These results are reported by a static tool designed by myself. Link: https://lkml.kernel.org/r/20230113125501.760324-1-baijiaju1990@gmail.com Reported-by: TOTE Robot <oslab@tsinghua.edu.cn> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-10ring-buffer: Handle race between rb_move_tail and rb_check_pagesMukesh Ojha1-32/+10
commit 8843e06f67b14f71c044bf6267b2387784c7e198 upstream. It seems a data race between ring_buffer writing and integrity check. That is, RB_FLAG of head_page is been updating, while at same time RB_FLAG was cleared when doing integrity check rb_check_pages(): rb_check_pages() rb_handle_head_page(): -------- -------- rb_head_page_deactivate() rb_head_page_set_normal() rb_head_page_activate() We do intergrity test of the list to check if the list is corrupted and it is still worth doing it. So, let's refactor rb_check_pages() such that we no longer clear and set flag during the list sanity checking. [1] and [2] are the test to reproduce and the crash report respectively. 1: ``` read_trace.sh while true; do # the "trace" file is closed after read head -1 /sys/kernel/tracing/trace > /dev/null done ``` ``` repro.sh sysctl -w kernel.panic_on_warn=1 # function tracer will writing enough data into ring_buffer echo function > /sys/kernel/tracing/current_tracer ./read_trace.sh & ./read_trace.sh & ./read_trace.sh & ./read_trace.sh & ./read_trace.sh & ./read_trace.sh & ./read_trace.sh & ./read_trace.sh & ``` 2: ------------[ cut here ]------------ WARNING: CPU: 9 PID: 62 at kernel/trace/ring_buffer.c:2653 rb_move_tail+0x450/0x470 Modules linked in: CPU: 9 PID: 62 Comm: ksoftirqd/9 Tainted: G W 6.2.0-rc6+ Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 RIP: 0010:rb_move_tail+0x450/0x470 Code: ff ff 4c 89 c8 f0 4d 0f b1 02 48 89 c2 48 83 e2 fc 49 39 d0 75 24 83 e0 03 83 f8 02 0f 84 e1 fb ff ff 48 8b 57 10 f0 ff 42 08 <0f> 0b 83 f8 02 0f 84 ce fb ff ff e9 db RSP: 0018:ffffb5564089bd00 EFLAGS: 00000203 RAX: 0000000000000000 RBX: ffff9db385a2bf81 RCX: ffffb5564089bd18 RDX: ffff9db281110100 RSI: 0000000000000fe4 RDI: ffff9db380145400 RBP: ffff9db385a2bf80 R08: ffff9db385a2bfc0 R09: ffff9db385a2bfc2 R10: ffff9db385a6c000 R11: ffff9db385a2bf80 R12: 0000000000000000 R13: 00000000000003e8 R14: ffff9db281110100 R15: ffffffffbb006108 FS: 0000000000000000(0000) GS:ffff9db3bdcc0000(0000) kn