CVE-2025-38424

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> perf: Fix sample vs do_exit()<br /> <br /> Baisheng Gao reported an ARM64 crash, which Mark decoded as being a<br /> synchronous external abort -- most likely due to trying to access<br /> MMIO in bad ways.<br /> <br /> The crash further shows perf trying to do a user stack sample while in<br /> exit_mmap()&amp;#39;s tlb_finish_mmu() -- i.e. while tearing down the address<br /> space it is trying to access.<br /> <br /> It turns out that we stop perf after we tear down the userspace mm; a<br /> receipie for disaster, since perf likes to access userspace for<br /> various reasons.<br /> <br /> Flip this order by moving up where we stop perf in do_exit().<br /> <br /> Additionally, harden PERF_SAMPLE_CALLCHAIN and PERF_SAMPLE_STACK_USER<br /> to abort when the current task does not have an mm (exit_mm() makes<br /> sure to set current-&gt;mm = NULL; before commencing with the actual<br /> teardown). Such that CPU wide events don&amp;#39;t trip on this same problem.