High · published July 25, 2025
In the Linux kernel, the following vulnerability has been resolved:
perf: Fix sample vs do_exit()
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.
| Product | Versions | Fixed in |
|---|---|---|
| linux/linux_kernel | ≥ 3.7, < 5.4.295 | 5.4.295 |
| linux/linux_kernel | ≥ 5.5, < 5.10.239 | 5.10.239 |
| linux/linux_kernel | ≥ 5.11, < 5.15.186 | 5.15.186 |
| linux/linux_kernel | ≥ 5.16, < 6.1.142 | 6.1.142 |
| linux/linux_kernel | ≥ 6.2, < 6.6.95 | 6.6.95 |
| linux/linux_kernel | ≥ 6.7, < 6.12.35 | 6.12.35 |
| linux/linux_kernel | ≥ 6.13, < 6.15.4 | 6.15.4 |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |
| debian/debian_linux | all versions | — |