Date: Fri, 3 Aug 2018 14:45:53 +0000 (UTC) From: Alan Somers <asomers@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r337258 - stable/10/sys/kern Message-ID: <201808031445.w73EjraV086933@repo.freebsd.org>
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Author: asomers Date: Fri Aug 3 14:45:53 2018 New Revision: 337258 URL: https://svnweb.freebsd.org/changeset/base/337258 Log: MFC r336205: Don't acquire evclass_lock with a spinlock held When the "pc" audit class is enabled and auditd is running, witness will panic during thread exit because au_event_class tries to lock an rwlock while holding a spinlock acquired upstack by thread_exit. To fix this, move AUDIT_SYSCALL_EXIT futher upstack, before the spinlock is acquired. Of thread_exit's 16 callers, it's only necessary to call AUDIT_SYSCALL_EXIT from two, exit1 (for exiting processes) and kern_thr_exit (for exiting threads). The other callers are all kernel threads, which needen't call AUDIT_SYSCALL_EXIT because since they can't make syscalls there will be nothing to audit. And exit1 already does call AUDIT_SYSCALL_EXIT, making the second call in thread_exit redundant for that case. PR: 228444 Reported by: aniketp Reviewed by: aniketp, kib Differential Revision: https://reviews.freebsd.org/D16210 Modified: stable/10/sys/kern/kern_thr.c stable/10/sys/kern/kern_thread.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/kern/kern_thr.c ============================================================================== --- stable/10/sys/kern/kern_thr.c Fri Aug 3 14:37:23 2018 (r337257) +++ stable/10/sys/kern/kern_thr.c Fri Aug 3 14:45:53 2018 (r337258) @@ -362,6 +362,11 @@ kern_thr_exit(struct thread *td) racct_sub(p, RACCT_NTHR, 1); tdsigcleanup(td); umtx_thread_exit(td); + +#ifdef AUDIT + AUDIT_SYSCALL_EXIT(0, td); +#endif + PROC_SLOCK(p); thread_stopped(p); thread_exit(); Modified: stable/10/sys/kern/kern_thread.c ============================================================================== --- stable/10/sys/kern/kern_thread.c Fri Aug 3 14:37:23 2018 (r337257) +++ stable/10/sys/kern/kern_thread.c Fri Aug 3 14:45:53 2018 (r337258) @@ -418,9 +418,6 @@ thread_exit(void) SDT_PROBE0(proc, , , lwp__exit); KASSERT(TAILQ_EMPTY(&td->td_sigqueue.sq_list), ("signal pending")); -#ifdef AUDIT - AUDIT_SYSCALL_EXIT(0, td); -#endif /* * drop FPU & debug register state storage, or any other * architecture specific resources that
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