CVE-2025-21889

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> perf/core: Add RCU read lock protection to perf_iterate_ctx()<br /> <br /> The perf_iterate_ctx() function performs RCU list traversal but<br /> currently lacks RCU read lock protection. This causes lockdep warnings<br /> when running perf probe with unshare(1) under CONFIG_PROVE_RCU_LIST=y:<br /> <br /> WARNING: suspicious RCU usage<br /> kernel/events/core.c:8168 RCU-list traversed in non-reader section!!<br /> <br /> Call Trace:<br /> lockdep_rcu_suspicious<br /> ? perf_event_addr_filters_apply<br /> perf_iterate_ctx<br /> perf_event_exec<br /> begin_new_exec<br /> ? load_elf_phdrs<br /> load_elf_binary<br /> ? lock_acquire<br /> ? find_held_lock<br /> ? bprm_execve<br /> bprm_execve<br /> do_execveat_common.isra.0<br /> __x64_sys_execve<br /> do_syscall_64<br /> entry_SYSCALL_64_after_hwframe<br /> <br /> This protection was previously present but was removed in commit<br /> bd2756811766 ("perf: Rewrite core context handling"). Add back the<br /> necessary rcu_read_lock()/rcu_read_unlock() pair around<br /> perf_iterate_ctx() call in perf_event_exec().<br /> <br /> [ mingo: Use scoped_guard() as suggested by Peter ]