user/sven/linux.git/kernel/events, branch v6.6.100

perf: Revert to requiring CAP_SYS_ADMIN for uprobes

2025-07-17T16:35:08Z

[ Upstream commit ba677dbe77af5ffe6204e0f3f547f3ba059c6302 ] Jann reports that uprobes can be used destructively when used in the middle of an instruction. The kernel only verifies there is a valid instruction at the requested offset, but due to variable instruction length cannot determine if this is an instruction as seen by the intended execution stream. Additionally, Mark Rutland notes that on architectures that mix data in the text segment (like arm64), a similar things can be done if the data word is 'mistaken' for an instruction. As such, require CAP_SYS_ADMIN for uprobes. Fixes: c9e0924e5c2b ("perf/core: open access to probes for CAP_PERFMON privileged process") Reported-by: Jann Horn Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/CAG48ez1n4520sq0XrWYDHKiKxE_+WCfAK+qt9qkY4ZiBGmL-5g@mail.gmail.com Signed-off-by: Sasha Levin

perf/core: Fix the WARN_ON_ONCE is out of lock protected region

2025-07-17T16:35:08Z

[ Upstream commit 7b4c5a37544ba22c6ebe72c0d4ea56c953459fa5 ] commit 3172fb986666 ("perf/core: Fix WARN in perf_cgroup_switch()") try to fix a concurrency problem between perf_cgroup_switch and perf_cgroup_event_disable. But it does not to move the WARN_ON_ONCE into lock-protected region, so the warning is still be triggered. Fixes: 3172fb986666 ("perf/core: Fix WARN in perf_cgroup_switch()") Signed-off-by: Luo Gengkun Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20250626135403.2454105-1-luogengkun@huaweicloud.com Signed-off-by: Sasha Levin

perf/core: Fix WARN in perf_cgroup_switch()

2025-06-27T10:09:04Z

[ Upstream commit 3172fb986666dfb71bf483b6d3539e1e587fa197 ] There may be concurrency between perf_cgroup_switch and perf_cgroup_event_disable. Consider the following scenario: after a new perf cgroup event is created on CPU0, the new event may not trigger a reprogramming, causing ctx->is_active to be 0. In this case, when CPU1 disables this perf event, it executes __perf_remove_from_context-> list _del_event->perf_cgroup_event_disable on CPU1, which causes a race with perf_cgroup_switch running on CPU0. The following describes the details of this concurrency scenario: CPU0 CPU1 perf_cgroup_switch: ... # cpuctx->cgrp is not NULL here if (READ_ONCE(cpuctx->cgrp) == NULL) return; perf_remove_from_context: ... raw_spin_lock_irq(&ctx->lock); ... # ctx->is_active == 0 because reprogramm is not # tigger, so CPU1 can do __perf_remove_from_context # for CPU0 __perf_remove_from_context: perf_cgroup_event_disable: ... if (--ctx->nr_cgroups) ... # this warning will happened because CPU1 changed # ctx.nr_cgroups to 0. WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0); [peterz: use guard instead of goto unlock] Fixes: db4a835601b7 ("perf/core: Set cgroup in CPU contexts for new cgroup events") Signed-off-by: Luo Gengkun Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20250604033924.3914647-3-luogengkun@huaweicloud.com Signed-off-by: Sasha Levin

perf: Fix cgroup state vs ERROR

2025-06-27T10:09:03Z

[ Upstream commit 61988e36dc5457cdff7ae7927e8d9ad1419ee998 ] While chasing down a missing perf_cgroup_event_disable() elsewhere, Leo Yan found that both perf_put_aux_event() and perf_remove_sibling_event() were also missing one. Specifically, the rule is that events that switch to OFF,ERROR need to call perf_cgroup_event_disable(). Unify the disable paths to ensure this. Fixes: ab43762ef010 ("perf: Allow normal events to output AUX data") Fixes: 9f0c4fa111dc ("perf/core: Add a new PERF_EV_CAP_SIBLING event capability") Reported-by: Leo Yan Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20250605123343.GD35970@noisy.programming.kicks-ass.net Signed-off-by: Sasha Levin

perf: Fix sample vs do_exit()

2025-06-27T10:09:03Z

[ Upstream commit 4f6fc782128355931527cefe3eb45338abd8ab39 ] Baisheng Gao reported an ARM64 crash, which Mark decoded as being a synchronous external abort -- most likely due to trying to access MMIO in bad ways. The crash further shows perf trying to do a user stack sample while in exit_mmap()'s tlb_finish_mmu() -- i.e. while tearing down the address space it is trying to access. It turns out that we stop perf after we tear down the userspace mm; a receipie for disaster, since perf likes to access userspace for various reasons. Flip this order by moving up where we stop perf in do_exit(). Additionally, harden PERF_SAMPLE_CALLCHAIN and PERF_SAMPLE_STACK_USER to abort when the current task does not have an mm (exit_mm() makes sure to set current->mm = NULL; before commencing with the actual teardown). Such that CPU wide events don't trip on this same problem. Fixes: c5ebcedb566e ("perf: Add ability to attach user stack dump to sample") Reported-by: Baisheng Gao Suggested-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20250605110815.GQ39944@noisy.programming.kicks-ass.net Signed-off-by: Sasha Levin

perf: Ensure bpf_perf_link path is properly serialized

2025-06-19T13:28:43Z

[ Upstream commit 7ed9138a72829d2035ecbd8dbd35b1bc3c137c40 ] Ravi reported that the bpf_perf_link_attach() usage of perf_event_set_bpf_prog() is not serialized by ctx->mutex, unlike the PERF_EVENT_IOC_SET_BPF case. Reported-by: Ravi Bangoria Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Ravi Bangoria Link: https://lkml.kernel.org/r/20250307193305.486326750@infradead.org Signed-off-by: Sasha Levin

perf/core: Fix broken throttling when max_samples_per_tick=1

2025-06-19T13:28:02Z

[ Upstream commit f51972e6f8b9a737b2b3eb588069acb538fa72de ] According to the throttling mechanism, the pmu interrupts number can not exceed the max_samples_per_tick in one tick. But this mechanism is ineffective when max_samples_per_tick=1, because the throttling check is skipped during the first interrupt and only performed when the second interrupt arrives. Perhaps this bug may cause little influence in one tick, but if in a larger time scale, the problem can not be underestimated. When max_samples_per_tick = 1: Allowed-interrupts-per-second max-samples-per-second default-HZ ARCH 200 100 100 X86 500 250 250 ARM64 ... Obviously, the pmu interrupt number far exceed the user's expect. Fixes: e050e3f0a71b ("perf: Fix broken interrupt rate throttling") Signed-off-by: Qing Wang Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20250405141635.243786-3-wangqing7171@gmail.com Signed-off-by: Sasha Levin

perf: Avoid the read if the count is already updated

2025-06-04T12:42:13Z

[ Upstream commit 8ce939a0fa194939cc1f92dbd8bc1a7806e7d40a ] The event may have been updated in the PMU-specific implementation, e.g., Intel PEBS counters snapshotting. The common code should not read and overwrite the value. The PERF_SAMPLE_READ in the data->sample_type can be used to detect whether the PMU-specific value is available. If yes, avoid the pmu->read() in the common code. Add a new flag, skip_read, to track the case. Factor out a perf_pmu_read() to clean up the code. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20250121152303.3128733-3-kan.liang@linux.intel.com Signed-off-by: Sasha Levin

perf/hw_breakpoint: Return EOPNOTSUPP for unsupported breakpoint type

2025-06-04T12:42:03Z

[ Upstream commit 061c991697062f3bf87b72ed553d1d33a0e370dd ] Currently, __reserve_bp_slot() returns -ENOSPC for unsupported breakpoint types on the architecture. For example, powerpc does not support hardware instruction breakpoints. This causes the perf_skip BPF selftest to fail, as neither ENOENT nor EOPNOTSUPP is returned by perf_event_open for unsupported breakpoint types. As a result, the test that should be skipped for this arch is not correctly identified. To resolve this, hw_breakpoint_event_init() should exit early by checking for unsupported breakpoint types using hw_breakpoint_slots_cached() and return the appropriate error (-EOPNOTSUPP). Signed-off-by: Saket Kumar Bhaskar Signed-off-by: Ingo Molnar Cc: Marco Elver Cc: Dmitry Vyukov Cc: Ian Rogers Cc: Frederic Weisbecker Link: https://lore.kernel.org/r/20250303092451.1862862-1-skb99@linux.ibm.com Signed-off-by: Sasha Levin

perf/core: Fix WARN_ON(!ctx) in __free_event() for partial init

2025-05-02T05:50:58Z

[ Upstream commit 0ba3a4ab76fd3367b9cb680cad70182c896c795c ] Move the get_ctx(child_ctx) call and the child_event->ctx assignment to occur immediately after the child event is allocated. Ensure that child_event->ctx is non-NULL before any subsequent error path within inherit_event calls free_event(), satisfying the assumptions of the cleanup code. Details: There's no clear Fixes tag, because this bug is a side-effect of multiple interacting commits over time (up to 15 years old), not a single regression. The code initially incremented refcount then assigned context immediately after the child_event was created. Later, an early validity check for child_event was added before the refcount/assignment. Even later, a WARN_ON_ONCE() cleanup check was added, assuming event->ctx is valid if the pmu_ctx is valid. The problem is that the WARN_ON_ONCE() could trigger after the initial check passed but before child_event->ctx was assigned, violating its precondition. The solution is to assign child_event->ctx right after its initial validation. This ensures the context exists for any subsequent checks or cleanup routines, resolving the WARN_ON_ONCE(). To resolve it, defer the refcount update and child_event->ctx assignment directly after child_event->pmu_ctx is set but before checking if the parent event is orphaned. The cleanup routine depends on event->pmu_ctx being non-NULL before it verifies event->ctx is non-NULL. This also maintains the author's original intent of passing in child_ctx to find_get_pmu_context before its refcount/assignment. [ mingo: Expanded the changelog from another email by Gabriel Shahrouzi. ] Reported-by: syzbot+ff3aa851d46ab82953a3@syzkaller.appspotmail.com Signed-off-by: Gabriel Shahrouzi Signed-off-by: Ingo Molnar Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Kan Liang Cc: Oleg Nesterov Cc: Alexander Shishkin Link: https://lore.kernel.org/r/20250405203036.582721-1-gshahrouzi@gmail.com Closes: https://syzkaller.appspot.com/bug?extid=ff3aa851d46ab82953a3 Signed-off-by: Sasha Levin