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2025-05-02ftrace: Add cond_resched() to ftrace_graph_set_hash()zhoumin1-0/+1
commit 42ea22e754ba4f2b86f8760ca27f6f71da2d982c upstream. When the kernel contains a large number of functions that can be traced, the loop in ftrace_graph_set_hash() may take a lot of time to execute. This may trigger the softlockup watchdog. Add cond_resched() within the loop to allow the kernel to remain responsive even when processing a large number of functions. This matches the cond_resched() that is used in other locations of the code that iterates over all functions that can be traced. Cc: stable@vger.kernel.org Fixes: b9b0c831bed26 ("ftrace: Convert graph filter to use hash tables") Link: https://lore.kernel.org/tencent_3E06CE338692017B5809534B9C5C03DA7705@qq.com Signed-off-by: zhoumin <teczm@foxmail.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-05-02locking/lockdep: Decrease nr_unused_locks if lock unused in zap_class()Boqun Feng1-0/+3
commit 495f53d5cca0f939eaed9dca90b67e7e6fb0e30c upstream. Currently, when a lock class is allocated, nr_unused_locks will be increased by 1, until it gets used: nr_unused_locks will be decreased by 1 in mark_lock(). However, one scenario is missed: a lock class may be zapped without even being used once. This could result into a situation that nr_unused_locks != 0 but no unused lock class is active in the system, and when `cat /proc/lockdep_stats`, a WARN_ON() will be triggered in a CONFIG_DEBUG_LOCKDEP=y kernel: [...] DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused) [...] WARNING: CPU: 41 PID: 1121 at kernel/locking/lockdep_proc.c:283 lockdep_stats_show+0xba9/0xbd0 And as a result, lockdep will be disabled after this. Therefore, nr_unused_locks needs to be accounted correctly at zap_class() time. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Waiman Long <longman@redhat.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250326180831.510348-1-boqun.feng@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-05-02tracing: fix return value in __ftrace_event_enable_disable for ↵Gabriele Paoloni1-1/+3
TRACE_REG_UNREGISTER [ Upstream commit 0c588ac0ca6c22b774d9ad4a6594681fdfa57d9d ] When __ftrace_event_enable_disable invokes the class callback to unregister the event, the return value is not reported up to the caller, hence leading to event unregister failures being silently ignored. This patch assigns the ret variable to the invocation of the event unregister callback, so that its return value is stored and reported to the caller, and it raises a warning in case of error. Link: https://lore.kernel.org/20250321170821.101403-1-gpaoloni@redhat.com Signed-off-by: Gabriele Paoloni <gpaoloni@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10tracing: Fix use-after-free in print_graph_function_flags during tracer ↵Tengda Wu3-4/+1
switching commit 7f81f27b1093e4895e87b74143c59c055c3b1906 upstream. Kairui reported a UAF issue in print_graph_function_flags() during ftrace stress testing [1]. This issue can be reproduced if puting a 'mdelay(10)' after 'mutex_unlock(&trace_types_lock)' in s_start(), and executing the following script: $ echo function_graph > current_tracer $ cat trace > /dev/null & $ sleep 5 # Ensure the 'cat' reaches the 'mdelay(10)' point $ echo timerlat > current_tracer The root cause lies in the two calls to print_graph_function_flags within print_trace_line during each s_show(): * One through 'iter->trace->print_line()'; * Another through 'event->funcs->trace()', which is hidden in print_trace_fmt() before print_trace_line returns. Tracer switching only updates the former, while the latter continues to use the print_line function of the old tracer, which in the script above is print_graph_function_flags. Moreover, when switching from the 'function_graph' tracer to the 'timerlat' tracer, s_start only calls graph_trace_close of the 'function_graph' tracer to free 'iter->private', but does not set it to NULL. This provides an opportunity for 'event->funcs->trace()' to use an invalid 'iter->private'. To fix this issue, set 'iter->private' to NULL immediately after freeing it in graph_trace_close(), ensuring that an invalid pointer is not passed to other tracers. Additionally, clean up the unnecessary 'iter->private = NULL' during each 'cat trace' when using wakeup and irqsoff tracers. [1] https://lore.kernel.org/all/20231112150030.84609-1-ryncsn@gmail.com/ Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Zheng Yejian <zhengyejian1@huawei.com> Link: https://lore.kernel.org/20250320122137.23635-1-wutengda@huaweicloud.com Fixes: eecb91b9f98d ("tracing: Fix memleak due to race between current_tracer and trace") Closes: https://lore.kernel.org/all/CAMgjq7BW79KDSCyp+tZHjShSzHsScSiJxn5ffskp-QzVM06fxw@mail.gmail.com/ Reported-by: Kairui Song <kasong@tencent.com> Signed-off-by: Tengda Wu <wutengda@huaweicloud.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-10locking/semaphore: Use wake_q to wake up processes outside lock critical sectionWaiman Long1-4/+9
[ Upstream commit 85b2b9c16d053364e2004883140538e73b333cdb ] A circular lock dependency splat has been seen involving down_trylock(): ====================================================== WARNING: possible circular locking dependency detected 6.12.0-41.el10.s390x+debug ------------------------------------------------------ dd/32479 is trying to acquire lock: 0015a20accd0d4f8 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x26/0x90 but task is already holding lock: 000000017e461698 (&zone->lock){-.-.}-{2:2}, at: rmqueue_bulk+0xac/0x8f0 the existing dependency chain (in reverse order) is: -> #4 (&zone->lock){-.-.}-{2:2}: -> #3 (hrtimer_bases.lock){-.-.}-{2:2}: -> #2 (&rq->__lock){-.-.}-{2:2}: -> #1 (&p->pi_lock){-.-.}-{2:2}: -> #0 ((console_sem).lock){-.-.}-{2:2}: The console_sem -> pi_lock dependency is due to calling try_to_wake_up() while holding the console_sem raw_spinlock. This dependency can be broken by using wake_q to do the wakeup instead of calling try_to_wake_up() under the console_sem lock. This will also make the semaphore's raw_spinlock become a terminal lock without taking any further locks underneath it. The hrtimer_bases.lock is a raw_spinlock while zone->lock is a spinlock. The hrtimer_bases.lock -> zone->lock dependency happens via the debug_objects_fill_pool() helper function in the debugobjects code. -> #4 (&zone->lock){-.-.}-{2:2}: __lock_acquire+0xe86/0x1cc0 lock_acquire.part.0+0x258/0x630 lock_acquire+0xb8/0xe0 _raw_spin_lock_irqsave+0xb4/0x120 rmqueue_bulk+0xac/0x8f0 __rmqueue_pcplist+0x580/0x830 rmqueue_pcplist+0xfc/0x470 rmqueue.isra.0+0xdec/0x11b0 get_page_from_freelist+0x2ee/0xeb0 __alloc_pages_noprof+0x2c2/0x520 alloc_pages_mpol_noprof+0x1fc/0x4d0 alloc_pages_noprof+0x8c/0xe0 allocate_slab+0x320/0x460 ___slab_alloc+0xa58/0x12b0 __slab_alloc.isra.0+0x42/0x60 kmem_cache_alloc_noprof+0x304/0x350 fill_pool+0xf6/0x450 debug_object_activate+0xfe/0x360 enqueue_hrtimer+0x34/0x190 __run_hrtimer+0x3c8/0x4c0 __hrtimer_run_queues+0x1b2/0x260 hrtimer_interrupt+0x316/0x760 do_IRQ+0x9a/0xe0 do_irq_async+0xf6/0x160 Normally a raw_spinlock to spinlock dependency is not legitimate and will be warned if CONFIG_PROVE_RAW_LOCK_NESTING is enabled, but debug_objects_fill_pool() is an exception as it explicitly allows this dependency for non-PREEMPT_RT kernel without causing PROVE_RAW_LOCK_NESTING lockdep splat. As a result, this dependency is legitimate and not a bug. Anyway, semaphore is the only locking primitive left that is still using try_to_wake_up() to do wakeup inside critical section, all the other locking primitives had been migrated to use wake_q to do wakeup outside of the critical section. It is also possible that there are other circular locking dependencies involving printk/console_sem or other existing/new semaphores lurking somewhere which may show up in the future. Let just do the migration now to wake_q to avoid headache like this. Reported-by: yzbot+ed801a886dfdbfe7136d@syzkaller.appspotmail.com Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250307232717.1759087-3-boqun.feng@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10sched/deadline: Use online cpus for validating runtimeShrikanth Hegde1-1/+1
[ Upstream commit 14672f059d83f591afb2ee1fff56858efe055e5a ] The ftrace selftest reported a failure because writing -1 to sched_rt_runtime_us returns -EBUSY. This happens when the possible CPUs are different from active CPUs. Active CPUs are part of one root domain, while remaining CPUs are part of def_root_domain. Since active cpumask is being used, this results in cpus=0 when a non active CPUs is used in the loop. Fix it by looping over the online CPUs instead for validating the bandwidth calculations. Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Juri Lelli <juri.lelli@redhat.com> Link: https://lore.kernel.org/r/20250306052954.452005-2-sshegde@linux.ibm.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10ring-buffer: Fix bytes_dropped calculation issueFeng Yang1-2/+2
[ Upstream commit c73f0b69648501978e8b3e8fa7eef7f4197d0481 ] The calculation of bytes-dropped and bytes_dropped_nested is reversed. Although it does not affect the final calculation of total_dropped, it should still be modified. Link: https://lore.kernel.org/20250223070106.6781-1-yangfeng59949@163.com Fixes: 6c43e554a2a5 ("ring-buffer: Add ring buffer startup selftest") Signed-off-by: Feng Yang <yangfeng@kylinos.cn> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10kexec: initialize ELF lowest address to ULONG_MAXSourabh Jain1-1/+1
[ Upstream commit 9986fb5164c8b21f6439cfd45ba36d8cc80c9710 ] Patch series "powerpc/crash: use generic crashkernel reservation", v3. Commit 0ab97169aa05 ("crash_core: add generic function to do reservation") added a generic function to reserve crashkernel memory. So let's use the same function on powerpc and remove the architecture-specific code that essentially does the same thing. The generic crashkernel reservation also provides a way to split the crashkernel reservation into high and low memory reservations, which can be enabled for powerpc in the future. Additionally move powerpc to use generic APIs to locate memory hole for kexec segments while loading kdump kernel. This patch (of 7): kexec_elf_load() loads an ELF executable and sets the address of the lowest PT_LOAD section to the address held by the lowest_load_addr function argument. To determine the lowest PT_LOAD address, a local variable lowest_addr (type unsigned long) is initialized to UINT_MAX. After loading each PT_LOAD, its address is compared to lowest_addr. If a loaded PT_LOAD address is lower, lowest_addr is updated. However, setting lowest_addr to UINT_MAX won't work when the kernel image is loaded above 4G, as the returned lowest PT_LOAD address would be invalid. This is resolved by initializing lowest_addr to ULONG_MAX instead. This issue was discovered while implementing crashkernel high/low reservation on the PowerPC architecture. Link: https://lkml.kernel.org/r/20250131113830.925179-1-sourabhjain@linux.ibm.com Link: https://lkml.kernel.org/r/20250131113830.925179-2-sourabhjain@linux.ibm.com Fixes: a0458284f062 ("powerpc: Add support code for kexec_file_load()") Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com> Acked-by: Hari Bathini <hbathini@linux.ibm.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mahesh Salgaonkar <mahesh@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10bpf: Use preempt_count() directly in bpf_send_signal_common()Hou Tao1-1/+1
[ Upstream commit b4a8b5bba712a711d8ca1f7d04646db63f9c88f5 ] bpf_send_signal_common() uses preemptible() to check whether or not the current context is preemptible. If it is preemptible, it will use irq_work to send the signal asynchronously instead of trying to hold a spin-lock, because spin-lock is sleepable under PREEMPT_RT. However, preemptible() depends on CONFIG_PREEMPT_COUNT. When CONFIG_PREEMPT_COUNT is turned off (e.g., CONFIG_PREEMPT_VOLUNTARY=y), !preemptible() will be evaluated as 1 and bpf_send_signal_common() will use irq_work unconditionally. Fix it by unfolding "!preemptible()" and using "preempt_count() != 0 || irqs_disabled()" instead. Fixes: 87c544108b61 ("bpf: Send signals asynchronously if !preemptible") Signed-off-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/20250220042259.1583319-1-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10perf/ring_buffer: Allow the EPOLLRDNORM flag for pollTao Chen1-1/+1
[ Upstream commit c96fff391c095c11dc87dab35be72dee7d217cde ] The poll man page says POLLRDNORM is equivalent to POLLIN. For poll(), it seems that if user sets pollfd with POLLRDNORM in userspace, perf_poll will not return until timeout even if perf_output_wakeup called, whereas POLLIN returns. Fixes: 76369139ceb9 ("perf: Split up buffer handling from core code") Signed-off-by: Tao Chen <chen.dylane@linux.dev> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250314030036.2543180-1-chen.dylane@linux.dev Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10hrtimers: Mark is_migration_base() with __always_inlineAndy Shevchenko1-10/+12
[ Upstream commit 27af31e44949fa85550176520ef7086a0d00fd7b ] When is_migration_base() is unused, it prevents kernel builds with clang, `make W=1` and CONFIG_WERROR=y: kernel/time/hrtimer.c:156:20: error: unused function 'is_migration_base' [-Werror,-Wunused-function] 156 | static inline bool is_migration_base(struct hrtimer_clock_base *base) | ^~~~~~~~~~~~~~~~~ Fix this by marking it with __always_inline. [ tglx: Use __always_inline instead of __maybe_unused and move it into the usage sites conditional ] Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20250116160745.243358-1-andriy.shevchenko@linux.intel.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-13acct: perform last write from workqueueChristian Brauner1-50/+70
[ Upstream commit 56d5f3eba3f5de0efdd556de4ef381e109b973a9 ] In [1] it was reported that the acct(2) system call can be used to trigger NULL deref in cases where it is set to write to a file that triggers an internal lookup. This can e.g., happen when pointing acc(2) to /sys/power/resume. At the point the where the write to this file happens the calling task has already exited and called exit_fs(). A lookup will thus trigger a NULL-deref when accessing current->fs. Reorganize the code so that the the final write happens from the workqueue but with the caller's credentials. This preserves the (strange) permission model and has almost no regression risk. This api should stop to exist though. Link: https://lore.kernel.org/r/20250127091811.3183623-1-quzicheng@huawei.com [1] Link: https://lore.kernel.org/r/20250211-work-acct-v1-1-1c16aecab8b3@kernel.org Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Zicheng Qu <quzicheng@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-13kernel/acct.c: use dedicated helper to access rlimit valuesYang Yang1-1/+1
[ Upstream commit 3c91dda97eea704ac257ddb138d1154adab8db62 ] Use rlimit() helper instead of manually writing whole chain from task to rlimit value. See patch "posix-cpu-timers: Use dedicated helper to access rlimit values". Link: https://lkml.kernel.org/r/20210728030822.524789-1-yang.yang29@zte.com.cn Signed-off-by: Yang Yang <yang.yang29@zte.com.cn> Reported-by: Zeal Robot <zealci@zte.com.cn> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: sh_def@163.com <sh_def@163.com> Cc: Yang Yang <yang.yang29@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Stable-dep-of: 56d5f3eba3f5 ("acct: perform last write from workqueue") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-13kernel/acct.c: use #elif instead of #end and #elifHui Su1-5/+2
[ Upstream commit 35189b8ff18ee0c6f7c04f4c674584d1149d5c55 ] Cleanup: use #elif instead of #end and #elif. Link: https://lkml.kernel.org/r/20201015150736.GA91603@rlk Signed-off-by: Hui Su <sh_def@163.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Stable-dep-of: 56d5f3eba3f5 ("acct: perform last write from workqueue") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-13sched/core: Prevent rescheduling when interrupts are disabledThomas Gleixner1-1/+1
commit 82c387ef7568c0d96a918a5a78d9cad6256cfa15 upstream. David reported a warning observed while loop testing kexec jump: Interrupts enabled after irqrouter_resume+0x0/0x50 WARNING: CPU: 0 PID: 560 at drivers/base/syscore.c:103 syscore_resume+0x18a/0x220 kernel_kexec+0xf6/0x180 __do_sys_reboot+0x206/0x250 do_syscall_64+0x95/0x180 The corresponding interrupt flag trace: hardirqs last enabled at (15573): [<ffffffffa8281b8e>] __up_console_sem+0x7e/0x90 hardirqs last disabled at (15580): [<ffffffffa8281b73>] __up_console_sem+0x63/0x90 That means __up_console_sem() was invoked with interrupts enabled. Further instrumentation revealed that in the interrupt disabled section of kexec jump one of the syscore_suspend() callbacks woke up a task, which set the NEED_RESCHED flag. A later callback in the resume path invoked cond_resched() which in turn led to the invocation of the scheduler: __cond_resched+0x21/0x60 down_timeout+0x18/0x60 acpi_os_wait_semaphore+0x4c/0x80 acpi_ut_acquire_mutex+0x3d/0x100 acpi_ns_get_node+0x27/0x60 acpi_ns_evaluate+0x1cb/0x2d0 acpi_rs_set_srs_method_data+0x156/0x190 acpi_pci_link_set+0x11c/0x290 irqrouter_resume+0x54/0x60 syscore_resume+0x6a/0x200 kernel_kexec+0x145/0x1c0 __do_sys_reboot+0xeb/0x240 do_syscall_64+0x95/0x180 This is a long standing problem, which probably got more visible with the recent printk changes. Something does a task wakeup and the scheduler sets the NEED_RESCHED flag. cond_resched() sees it set and invokes schedule() from a completely bogus context. The scheduler enables interrupts after context switching, which causes the above warning at the end. Quite some of the code paths in syscore_suspend()/resume() can result in triggering a wakeup with the exactly same consequences. They might not have done so yet, but as they share a lot of code with normal operations it's just a question of time. The problem only affects the PREEMPT_NONE and PREEMPT_VOLUNTARY scheduling models. Full preemption is not affected as cond_resched() is disabled and the preemption check preemptible() takes the interrupt disabled flag into account. Cure the problem by adding a corresponding check into cond_resched(). Reported-by: David Woodhouse <dwmw@amazon.co.uk> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: David Woodhouse <dwmw@amazon.co.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: stable@vger.kernel.org Closes: https://lore.kernel.org/all/7717fe2ac0ce5f0a2c43fdab8b11f4483d54a2a4.camel@infradead.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13perf/core: Fix low freq setting via IOC_PERIODKan Liang1-8/+9
commit 0d39844150546fa1415127c5fbae26db64070dd3 upstream. A low attr::freq value cannot be set via IOC_PERIOD on some platforms. The perf_event_check_period() introduced in: 81ec3f3c4c4d ("perf/x86: Add check_period PMU callback") was intended to check the period, rather than the frequency. A low frequency may be mistakenly rejected by limit_period(). Fix it. Fixes: 81ec3f3c4c4d ("perf/x86: Add check_period PMU callback") Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Ravi Bangoria <ravi.bangoria@amd.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250117151913.3043942-2-kan.liang@linux.intel.com Closes: https://lore.kernel.org/lkml/20250115154949.3147-1-ravi.bangoria@amd.com/ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13ftrace: Avoid potential division by zero in function_stat_show()Nikolay Kuratov1-15/+12
commit a1a7eb89ca0b89dc1c326eeee2596f263291aca3 upstream. Check whether denominator expression x * (x - 1) * 1000 mod {2^32, 2^64} produce zero and skip stddev computation in that case. For now don't care about rec->counter * rec->counter overflow because rec->time * rec->time overflow will likely happen earlier. Cc: stable@vger.kernel.org Cc: Wen Yang <wenyang@linux.alibaba.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20250206090156.1561783-1-kniv@yandex-team.ru Fixes: e31f7939c1c27 ("ftrace: Avoid potential division by zero in function profiler") Signed-off-by: Nikolay Kuratov <kniv@yandex-team.ru> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13acct: block access to kernel internal filesystemsChristian Brauner1-0/+14
commit 890ed45bde808c422c3c27d3285fc45affa0f930 upstream. There's no point in allowing anything kernel internal nor procfs or sysfs. Link: https://lore.kernel.org/r/20250127091811.3183623-1-quzicheng@huawei.com Link: https://lore.kernel.org/r/20250211-work-acct-v1-2-1c16aecab8b3@kernel.org Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reported-by: Zicheng Qu <quzicheng@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13tasklet: Introduce new initialization APIRomain Perier1-1/+17
[ Upstream commit 12cc923f1ccc1df467e046b02a72c2b3b321b6a2 ] Nowadays, modern kernel subsystems that use callbacks pass the data structure associated with a given callback as argument to the callback. The tasklet subsystem remains one which passes an arbitrary unsigned long to the callback function. This has several problems: - This keeps an extra field for storing the argument in each tasklet data structure, it bloats the tasklet_struct structure with a redundant .data field - No type checking can be performed on this argument. Instead of using container_of() like other callback subsystems, it forces callbacks to do explicit type cast of the unsigned long argument into the required object type. - Buffer overflows can overwrite the .func and the .data field, so an attacker can easily overwrite the function and its first argument to whatever it wants. Add a new tasklet initialization API, via DECLARE_TASKLET() and tasklet_setup(), which will replace the existing ones. This work is greatly inspired by the timer_struct conversion series, see commit e99e88a9d2b0 ("treewide: setup_timer() -> timer_setup()") To avoid problems with both -Wcast-function-type (which is enabled in the kernel via -Wextra is several subsystems), and with mismatched function prototypes when build with Control Flow Integrity enabled, this adds the "use_callback" member to let the tasklet caller choose which union member to call through. Once all old API uses are removed, this and the .data member will be removed as well. (On 64-bit this does not grow the struct size as the new member fills the hole after atomic_t, which is also "int" sized.) Signed-off-by: Romain Perier <romain.perier@gmail.com> Co-developed-by: Allen Pais <allen.lkml@gmail.com> Signed-off-by: Allen Pais <allen.lkml@gmail.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Co-developed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Stable-dep-of: 90b7f2961798 ("net: usb: rtl8150: enable basic endpoint checking") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-13printk: Fix signed integer overflow when defining LOG_BUF_LEN_MAXKuan-Wei Chiu1-1/+1
[ Upstream commit 3d6f83df8ff2d5de84b50377e4f0d45e25311c7a ] Shifting 1 << 31 on a 32-bit int causes signed integer overflow, which leads to undefined behavior. To prevent this, cast 1 to u32 before performing the shift, ensuring well-defined behavior. This change explicitly avoids any potential overflow by ensuring that the shift occurs on an unsigned 32-bit integer. Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com> Acked-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20240928113608.1438087-1-visitorckw@gmail.com Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-13sched: Don't try to catch up excess steal time.Suleiman Souhlal1-2/+4
[ Upstream commit 108ad0999085df2366dd9ef437573955cb3f5586 ] When steal time exceeds the measured delta when updating clock_task, we currently try to catch up the excess in future updates. However, this results in inaccurate run times for the future things using clock_task, in some situations, as they end up getting additional steal time that did not actually happen. This is because there is a window between reading the elapsed time in update_rq_clock() and sampling the steal time in update_rq_clock_task(). If the VCPU gets preempted between those two points, any additional steal time is accounted to the outgoing task even though the calculated delta did not actually contain any of that "stolen" time. When this race happens, we can end up with steal time that exceeds the calculated delta, and the previous code would try to catch up that excess steal time in future clock updates, which is given to the next, incoming task, even though it did not actually have any time stolen. This behavior is particularly bad when steal time can be very long, which we've seen when trying to extend steal time to contain the duration that the host was suspended [0]. When this happens, clock_task stays frozen, during which the running task stays running for the whole duration, since its run time doesn't increase. However the race can happen even under normal operation. Ideally we would read the elapsed cpu time and the steal time atomically, to prevent this race from happening in the first place, but doing so is non-trivial. Since the time between those two points isn't otherwise accounted anywhere, neither to the outgoing task nor the incoming task (because the "end of outgoing task" and "start of incoming task" timestamps are the same), I would argue that the right thing to do is to simply drop any excess steal time, in order to prevent these issues. [0] https://lore.kernel.org/kvm/20240820043543.837914-1-suleiman@google.com/ Signed-off-by: Suleiman Souhlal <suleiman@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20241118043745.1857272-1-suleiman@google.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-13PM: hibernate: Add error handling for syscore_suspend()Wentao Liang1-1/+6
[ Upstream commit e20a70c572539a486dbd91b225fa6a194a5e2122 ] In hibernation_platform_enter(), the code did not check the return value of syscore_suspend(), potentially leading to a situation where syscore_resume() would be called even if syscore_suspend() failed. This could cause unpredictable behavior or system instability. Modify the code sequence in question to properly handle errors returned by syscore_suspend(). If an error occurs in the suspend path, the code now jumps to label 'Enable_irqs' skipping the syscore_resume() call and only enabling interrupts after setting the system state to SYSTEM_RUNNING. Fixes: 40dc166cb5dd ("PM / Core: Introduce struct syscore_ops for core subsystems PM") Signed-off-by: Wentao Liang <vulab@iscas.ac.cn> Link: https://patch.msgid.link/20250119143205.2103-1-vulab@iscas.ac.cn [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-13bpf: Send signals asynchronously if !preemptiblePuranjay Mohan1-1/+1
[ Upstream commit 87c544108b612512b254c8f79aa5c0a8546e2cc4 ] BPF programs can execute in all kinds of contexts and when a program running in a non-preemptible context uses the bpf_send_signal() kfunc, it will cause issues because this kfunc can sleep. Change `irqs_disabled()` to `!preemptible()`. Reported-by: syzbot+97da3d7e0112d59971de@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/67486b09.050a0220.253251.0084.GAE@google.com/ Fixes: 1bc7896e9ef4 ("bpf: Fix deadlock with rq_lock in bpf_send_signal()") Signed-off-by: Puranjay Mohan <puranjay@kernel.org> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20250115103647.38487-1-puranjay@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-13padata: fix sysfs store callback checkThomas Weißschuh1-1/+1
[ Upstream commit 9ff6e943bce67d125781fe4780a5d6f072dc44c0 ] padata_sysfs_store() was copied from padata_sysfs_show() but this check was not adapted. Today there is no attribute which can fail this check, but if there is one it may as well be correct. Fixes: 5e017dc3f8bc ("padata: Added sysfs primitives to padata subsystem") Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-01hrtimers: Handle CPU state correctly on hotplugKoichiro Den2-2/+11
commit 2f8dea1692eef2b7ba6a256246ed82c365fdc686 upstream. Consider a scenario where a CPU transitions from CPUHP_ONLINE to halfway through a CPU hotunplug down to CPUHP_HRTIMERS_PREPARE, and then back to CPUHP_ONLINE: Since hrtimers_prepare_cpu() does not run, cpu_base.hres_active remains set to 1 throughout. However, during a CPU unplug operation, the tick and the clockevents are shut down at CPUHP_AP_TICK_DYING. On return to the online state, for instance CFS incorrectly assumes that the hrtick is already active, and the chance of the clockevent device to transition to oneshot mode is also lost forever for the CPU, unless it goes back to a lower state than CPUHP_HRTIMERS_PREPARE once. This round-trip reveals another issue; cpu_base.online is not set to 1 after the transition, which appears as a WARN_ON_ONCE in enqueue_hrtimer(). Aside of that, the bulk of the per CPU state is not reset either, which means there are dangling pointers in the worst case. Address this by adding a corresponding startup() callback, which resets the stale per CPU state and sets the online flag. [ tglx: Make the new callback unconditionally available, remove the online modification in the prepare() callback and clear the remaining state in the starting callback instead of the prepare callback ] Fixes: 5c0930ccaad5 ("hrtimers: Push pending hrtimers away from outgoing CPU earlier") Signed-off-by: Koichiro Den <koichiro.den@canonical.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20241220134421.3809834-1-koichiro.den@canonical.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-01kheaders: Ignore silly-rename filesDavid Howells1-0/+1
[ Upstream commit 973b710b8821c3401ad7a25360c89e94b26884ac ] Tell tar to ignore silly-rename files (".__afs*" and ".nfs*") when building the header archive. These occur when a file that is open is unlinked locally, but hasn't yet been closed. Such files are visible to the user via the getdents() syscall and so programs may want to do things with them. During the kernel build, such files may be made during the processing of header files and the cleanup may get deferred by fput() which may result in tar seeing these files when it reads the directory, but they may have disappeared by the time it tries to open them, causing tar to fail with an error. Further, we don't want to include them in the tarball if they still exist. With CONFIG_HEADERS_INSTALL=y, something like the following may be seen: find: './kernel/.tmp_cpio_dir/include/dt-bindings/reset/.__afs2080': No such file or directory tar: ./include/linux/greybus/.__afs3C95: File removed before we read it The find warning doesn't seem to cause a problem. Fix this by telling tar when called from in gen_kheaders.sh to exclude such files. This only affects afs and nfs; cifs uses the Windows Hidden attribute to prevent the file from being seen. Signed-off-by: David Howells <dhowells@redhat.com> Link: https://lore.kernel.org/r/20241213135013.2964079-2-dhowells@redhat.com cc: Masahiro Yamada <masahiroy@kernel.org> cc: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org cc: linux-nfs@vger.kernel.org cc: linux-kernel@vger.kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-01-09ftrace: use preempt_enable/disable notrace macros to avoid double faultKoichiro Den1-2/+2
Since the backport commit eea46baf1451 ("ftrace: Fix possible use-after-free issue in ftrace_location()") on linux-5.4.y branch, the old ftrace_int3_handler()->ftrace_location() path has included rcu_read_lock(), which has mcount location inside and leads to potential double fault. Replace rcu_read_lock/unlock with preempt_enable/disable notrace macros so that the mcount location does not appear on the int3 handler path. This fix is specific to linux-5.4.y branch, the only branch still using ftrace_int3_handler with commit e60b613df8b6 ("ftrace: Fix possible use-after-free issue in ftrace_location()") backported. It also avoids the need to backport the code conversion to text_poke() on this branch. Reported-by: Koichiro Den <koichiro.den@canonical.com> Closes: https://lore.kernel.org/all/74gjhwxupvozwop7ndhrh7t5qeckomt7yqvkkbm5j2tlx6dkfk@rgv7sijvry2k Fixes: eea46baf1451 ("ftrace: Fix possible use-after-free issue in ftrace_location()") # linux-5.4.y Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Koichiro Den <koichiro.den@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-01-09bpf: fix potential error returnAnton Protopopov1-1/+5
[ Upstream commit c4441ca86afe4814039ee1b32c39d833c1a16bbc ] The bpf_remove_insns() function returns WARN_ON_ONCE(error), where error is a result of bpf_adj_branches(), and thus should be always 0 However, if for any reason it is not 0, then it will be converted to boolean by WARN_ON_ONCE and returned to user space as 1, not an actual error value. Fix this by returning the original err after the WARN check. Signed-off-by: Anton Protopopov <aspsk@isovalent.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20241210114245.836164-1-aspsk@isovalent.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-01-09tracing/kprobe: Make trace_kprobe's module callback called after jump_label ↵Masami Hiramatsu (Google)1-1/+1
update [ Upstream commit d685d55dfc86b1a4bdcec77c3c1f8a83f181264e ] Make sure the trace_kprobe's module notifer callback function is called after jump_label's callback is called. Since the trace_kprobe's callback eventually checks jump_label address during registering new kprobe on the loading module, jump_label must be updated before this registration happens. Link: https://lore.kernel.org/all/173387585556.995044.3157941002975446119.stgit@devnote2/ Fixes: 614243181050 ("tracing/kprobes: Support module init function probing") Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-19tracing/kprobes: Skip symbol counting logic for module symbols in ↵Nikolay Kuratov1-1/+1
create_local_trace_kprobe() commit b022f0c7e404 ("tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols") avoids checking number_of_same_symbols() for module symbol in __trace_kprobe_create(), but create_local_trace_kprobe() should avoid this check too. Doing this check leads to ENOENT for module_name:symbol_name constructions passed over perf_event_open. No bug in newer kernels as it was fixed more generally by commit 9d8616034f16 ("tracing/kprobes: Add symbol counting check when module loads") Link: https://lore.kernel.org/linux-trace-kernel/20240705161030.b3ddb33a8167013b9b1da202@kernel.org Fixes: b022f0c7e404 ("tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols") Signed-off-by: Nikolay Kuratov <kniv@yandex-team.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-14bpf, xdp: Update devmap comments to reflect napi/rcu usageJohn Fastabend1-10/+11
commit 42a84a8cd0ff0cbff5a4595e1304c4567a30267d upstream. Now that we rely on synchronize_rcu and call_rcu waiting to exit perempt-disable regions (NAPI) lets update the comments to reflect this. Fixes: 0536b85239b84 ("xdp: Simplify devmap cleanup") Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Björn Töpel <bjorn.topel@intel.com> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/1580084042-11598-2-git-send-email-john.fastabend@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-14bpf: fix OOB devmap writes when deleting elementsMaciej Fijalkowski1-3/+3
[ Upstream commit ab244dd7cf4c291f82faacdc50b45cc0f55b674d ] Jordy reported issue against XSKMAP which also applies to DEVMAP - the index used for accessing map entry, due to being a signed integer, causes the OOB writes. Fix is simple as changing the type from int to u32, however, when compared to XSKMAP case, one more thing needs to be addressed. When map is released from system via dev_map_free(), we iterate through all of the entries and an iterator variable is also an int, which implies OOB accesses. Again, change it to be u32. Example splat below: [ 160.724676] BUG: unable to handle page fault for address: ffffc8fc2c001000 [ 160.731662] #PF: supervisor read access in kernel mode [ 160.736876] #PF: error_code(0x0000) - not-present page [ 160.742095] PGD 0 P4D 0 [ 160.744678] Oops: Oops: 0000 [#1] PREEMPT SMP [ 160.749106] CPU: 1 UID: 0 PID: 520 Comm: kworker/u145:12 Not tainted 6.12.0-rc1+ #487 [ 160.757050] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019 [ 160.767642] Workqueue: events_unbound bpf_map_free_deferred [ 160.773308] RIP: 0010:dev_map_free+0x77/0x170 [ 160.777735] Code: 00 e8 fd 91 ed ff e8 b8 73 ed ff 41 83 7d 18 19 74 6e 41 8b 45 24 49 8b bd f8 00 00 00 31 db 85 c0 74 48 48 63 c3 48 8d 04 c7 <48> 8b 28 48 85 ed 74 30 48 8b 7d 18 48 85 ff 74 05 e8 b3 52 fa ff [ 160.796777] RSP: 0018:ffffc9000ee1fe38 EFLAGS: 00010202 [ 160.802086] RAX: ffffc8fc2c001000 RBX: 0000000080000000 RCX: 0000000000000024 [ 160.809331] RDX: 0000000000000000 RSI: 0000000000000024 RDI: ffffc9002c001000 [ 160.816576] RBP: 0000000000000000 R08: 0000000000000023 R09: 0000000000000001 [ 160.823823] R10: 0000000000000001 R11: 00000000000ee6b2 R12: dead000000000122 [ 160.831066] R13: ffff88810c928e00 R14: ffff8881002df405 R15: 0000000000000000 [ 160.838310] FS: 0000000000000000(0000) GS:ffff8897e0c40000(0000) knlGS:0000000000000000 [ 160.846528] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 160.852357] CR2: ffffc8fc2c001000 CR3: 0000000005c32006 CR4: 00000000007726f0 [ 160.859604] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 160.866847] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 160.874092] PKRU: 55555554 [ 160.876847] Call Trace: [ 160.879338] <TASK> [ 160.881477] ? __die+0x20/0x60 [ 160.884586] ? page_fault_oops+0x15a/0x450 [ 160.888746] ? search_extable+0x22/0x30 [ 160.892647] ? search_bpf_extables+0x5f/0x80 [ 160.896988] ? exc_page_fault+0xa9/0x140 [ 160.900973] ? asm_exc_page_fault+0x22/0x30 [ 160.905232] ? dev_map_free+0x77/0x170 [ 160.909043] ? dev_map_free+0x58/0x170 [ 160.912857] bpf_map_free_deferred+0x51/0x90 [ 160.917196] process_one_work+0x142/0x370 [ 160.921272] worker_thread+0x29e/0x3b0 [ 160.925082] ? rescuer_thread+0x4b0/0x4b0 [ 160.929157] kthread+0xd4/0x110 [ 160.932355] ? kthread_park+0x80/0x80 [ 160.936079] ret_from_fork+0x2d/0x50 [ 160.943396] ? kthread_park+0x80/0x80 [ 160.950803] ret_from_fork_asm+0x11/0x20 [ 160.958482] </TASK> Fixes: 546ac1ffb70d ("bpf: add devmap, a map for storing net device references") CC: stable@vger.kernel.org Reported-by: Jordy Zomer <jordyzomer@google.com> Suggested-by: Jordy Zomer <jordyzomer@google.com> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/r/20241122121030.716788-3-maciej.fijalkowski@intel.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14xdp: Simplify devmap cleanupBjörn Töpel1-38/+5
[ Upstream commit 0536b85239b8440735cdd910aae0eb076ebbb439 ] After the RCU flavor consolidation [1], call_rcu() and synchronize_rcu() waits for preempt-disable regions (NAPI) in addition to the read-side critical sections. As a result of this, the cleanup code in devmap can be simplified * There is no longer a need to flush in __dev_map_entry_free, since we know that this has been done when the call_rcu() callback is triggered. * When freeing the map, there is no need to explicitly wait for a flush. It's guaranteed to be done after the synchronize_rcu() call in dev_map_free(). The rcu_barrier() is still needed, so that the map is not freed prior the elements. [1] https://lwn.net/Articles/777036/ Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20191219061006.21980-2-bjorn.topel@gmail.com Stable-dep-of: ab244dd7cf4c ("bpf: fix OOB devmap writes when deleting elements") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14tracing: Use atomic64_inc_return() in trace_clock_counter()Uros Bizjak1-1/+1
[ Upstream commit eb887c4567d1b0e7684c026fe7df44afa96589e6 ] Use atomic64_inc_return(&ref) instead of atomic64_add_return(1, &ref) to use optimized implementation and ease register pressure around the primitive for targets that implement optimized variant. Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20241007085651.48544-1-ubizjak@gmail.com Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14tracing: Fix cmp_entries_dup() to respect sort() comparison rulesKuan-Wei Chiu1-5/+1
commit e63fbd5f6810ed756bbb8a1549c7d4132968baa9 upstream. The cmp_entries_dup() function used as the comparator for sort() violated the symmetry and transitivity properties required by the sorting algorithm. Specifically, it returned 1 whenever memcmp() was non-zero, which broke the following expectations: * Symmetry: If x < y, then y > x. * Transitivity: If x < y and y < z, then x < z. These violations could lead to incorrect sorting and failure to correctly identify duplicate elements. Fix the issue by directly returning the result of memcmp(), which adheres to the required comparison properties. Cc: stable@vger.kernel.org Fixes: 08d43a5fa063 ("tracing: Add lock-free tracing_map") Link: https://lore.kernel.org/20241203202228.1274403-1-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-14bpf: Fix exact match conditions in trie_get_next_key()Hou Tao1-2/+2
[ Upstream commit 27abc7b3fa2e09bbe41e2924d328121546865eda ] trie_get_next_key() uses node->prefixlen == key->prefixlen to identify an exact match, However, it is incorrect because when the target key doesn't fully match the found node (e.g., node->prefixlen != matchlen), these two nodes may also have the same prefixlen. It will return expected result when the passed key exist in the trie. However when a recently-deleted key or nonexistent key is passed to trie_get_next_key(), it may skip keys and return incorrect result. Fix it by using node->prefixlen == matchlen to identify exact matches. When the condition is true after t