Vulnerability in Linux

[ Description ]Official description

In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix NULL pmu_ctx passed to pmu->sched_task() perf_pmu_sched_task() returns early when cpuctx->task_ctx is set, and cpc->task_epc is only non-NULL while a task context is scheduled in on this CPU. __perf_pmu_sched_task() therefore always passes NULL: Unable to handle kernel NULL pointer dereference at virtual address 00 pc : armv8pmu_sched_task+0x14/0x50 Call trace: armv8pmu_sched_task+0x14/0x50 (P) perf_pmu_sched_task+0xac/0x108 __perf_event_task_sched_out+0x6c/0xe0 Pass &cpc->epc instead, the CPU-wide context for this PMU, which the function already dereferences a few lines up to find pmu. armv8pmu_sched_task() is the only in-tree implementation that dereferences the argument, and it only reads ->pmu, so the oops needs BRBE, added in v6.17.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References

• git.kernel.org/stable/c/249a2bd87a0e57dc28f36e992807edc9cae309b5
• git.kernel.org/stable/c/36bb85cf36cab15fb611cb44b78a5df06e4e69a2
• git.kernel.org/stable/c/98181f9721f75f1a544dc563b0d8fed1d5c398d5
• git.kernel.org/stable/c/b5409311b606d536cc485f3706c242c2afa93edb
• git.kernel.org/stable/c/ec15f6a50183fc01f470af74ad49900fb3731fca