Date: Wed, 23 Oct 2019 17:58:20 +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: r353956 - head/sys/vm Message-ID: <201910231758.x9NHwK3Z079093@repo.freebsd.org>
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Author: markj Date: Wed Oct 23 17:58:19 2019 New Revision: 353956 URL: https://svnweb.freebsd.org/changeset/base/353956 Log: Verify identity after checking for WAITFAIL in vm_page_busy_acquire(). A caller that does not guarantee that a page's identity won't change while sleeping for a busy lock must specify either NOWAIT or WAITFAIL. Reported by: syzkaller Reviewed by: alc, kib Discussed with: jeff Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D22124 Modified: head/sys/vm/vm_page.c Modified: head/sys/vm/vm_page.c ============================================================================== --- head/sys/vm/vm_page.c Wed Oct 23 17:53:20 2019 (r353955) +++ head/sys/vm/vm_page.c Wed Oct 23 17:58:19 2019 (r353956) @@ -900,9 +900,11 @@ vm_page_busy_acquire(vm_page_t m, int allocflags) (allocflags & VM_ALLOC_SBUSY) != 0, locked); if (locked) VM_OBJECT_WLOCK(obj); - MPASS(m->object == obj || m->object == NULL); if ((allocflags & VM_ALLOC_WAITFAIL) != 0) return (FALSE); + KASSERT(m->object == obj || m->object == NULL, + ("vm_page_busy_acquire: page %p does not belong to %p", + m, obj)); } }
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