Date: Mon, 8 Dec 2014 16:02:02 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r275615 - head/sys/kern Message-ID: <201412081602.sB8G22F4085965@svn.freebsd.org>
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Author: kib Date: Mon Dec 8 16:02:02 2014 New Revision: 275615 URL: https://svnweb.freebsd.org/changeset/base/275615 Log: When process is exiting, check for suspension regardless of multithreaded status of the process. The stopped state must be cleared before P_WEXIT is set. A stop signal delivered just before first PROC_LOCK() block in exit1(9) would put the process into pending stop with P_WEXIT set or assertion triggered. Also recheck for the suspension after failed thread_single(9) call, since process lock could be dropped. Reported and tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week Modified: head/sys/kern/kern_exit.c Modified: head/sys/kern/kern_exit.c ============================================================================== --- head/sys/kern/kern_exit.c Mon Dec 8 15:47:52 2014 (r275614) +++ head/sys/kern/kern_exit.c Mon Dec 8 16:02:02 2014 (r275615) @@ -182,14 +182,15 @@ exit1(struct thread *td, int rv) * MUST abort all other threads before proceeding past here. */ PROC_LOCK(p); + /* + * First check if some other thread or external request got + * here before us. If so, act appropriately: exit or suspend. + * We must ensure that stop requests are handled before we set + * P_WEXIT. + */ + thread_suspend_check(0); while (p->p_flag & P_HADTHREADS) { /* - * First check if some other thread got here before us. - * If so, act appropriately: exit or suspend. - */ - thread_suspend_check(0); - - /* * Kill off the other threads. This requires * some co-operation from other parts of the kernel * so it may not be instantaneous. With this state set @@ -207,12 +208,18 @@ exit1(struct thread *td, int rv) * either be suspended there or exit. */ if (!thread_single(SINGLE_EXIT)) + /* + * All other activity in this process is now + * stopped. Threading support has been turned + * off. + */ break; - /* - * All other activity in this process is now stopped. - * Threading support has been turned off. + * Recheck for new stop or suspend requests which + * might appear while process lock was dropped in + * thread_single(). */ + thread_suspend_check(0); } KASSERT(p->p_numthreads == 1, ("exit1: proc %p exiting with %d threads", p, p->p_numthreads));
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