Date: Mon, 20 Apr 2020 14:45:18 +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: r360122 - head/sys/vm Message-ID: <202004201445.03KEjIbB018710@repo.freebsd.org>
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Author: markj Date: Mon Apr 20 14:45:17 2020 New Revision: 360122 URL: https://svnweb.freebsd.org/changeset/base/360122 Log: Handle trashed queue pointers in vm_page_acquire_unlocked(). vm_page_acquire_unlocked() relies on type-stability of vm_page structures and assumes that the listq linkage pointers always point to a vm_page or are NULL. QUEUE_MACRO_DEBUG_TRASH breaks that assumption, so add an explicit check for a trashed queue pointer before dereferencing. Reported and tested by: pho Reviewed by: kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D24472 Modified: head/sys/vm/vm_page.c Modified: head/sys/vm/vm_page.c ============================================================================== --- head/sys/vm/vm_page.c Mon Apr 20 14:24:13 2020 (r360121) +++ head/sys/vm/vm_page.c Mon Apr 20 14:45:17 2020 (r360122) @@ -4438,7 +4438,7 @@ vm_page_acquire_unlocked(vm_object_t object, vm_pindex * without barriers. Switch to radix to verify. */ if (prev == NULL || (m = TAILQ_NEXT(prev, listq)) == NULL || - m->pindex != pindex || + QMD_IS_TRASHED(m) || m->pindex != pindex || atomic_load_ptr(&m->object) != object) { prev = NULL; /*
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