Date: Tue, 1 Aug 2017 17:50:28 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r321884 - head/sys/kern Message-ID: <201708011750.v71HoSn6055271@repo.freebsd.org>
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Author: markj Date: Tue Aug 1 17:50:28 2017 New Revision: 321884 URL: https://svnweb.freebsd.org/changeset/base/321884 Log: Fix a witness assertion that fires when a lock type's class changes. When all instances of a lock type are destroyed (for example, after a module unload), the corresponding witness entry remains associated with that lock type. In this case, we shouldn't panic if a new instance of the lock type is created and its lock class does not match that recorded in the witness entry. Reviewed by: jhb MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D11788 Modified: head/sys/kern/subr_witness.c Modified: head/sys/kern/subr_witness.c ============================================================================== --- head/sys/kern/subr_witness.c Tue Aug 1 16:48:33 2017 (r321883) +++ head/sys/kern/subr_witness.c Tue Aug 1 17:50:28 2017 (r321884) @@ -1850,11 +1850,13 @@ enroll(const char *description, struct lock_class *loc found: w->w_refcount++; mtx_unlock_spin(&w_mtx); - if (lock_class != w->w_class) + if (w->w_refcount == 1) + w->w_class = lock_class; + else if (lock_class != w->w_class) kassert_panic( - "lock (%s) %s does not match earlier (%s) lock", - description, lock_class->lc_name, - w->w_class->lc_name); + "lock (%s) %s does not match earlier (%s) lock", + description, lock_class->lc_name, + w->w_class->lc_name); return (w); }
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