Date: Thu, 1 Oct 2009 12:50:26 +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: r197662 - head/sys/kern Message-ID: <200910011250.n91CoQ5G051511@svn.freebsd.org>
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Author: kib Date: Thu Oct 1 12:50:26 2009 New Revision: 197662 URL: http://svn.freebsd.org/changeset/base/197662 Log: Do not dereference vp->v_mount without holding vnode lock and checking that the vnode is not reclaimed. Noted by: Igor Sysoev <is rambler-co ru> MFC after: 1 week Modified: head/sys/kern/uipc_syscalls.c Modified: head/sys/kern/uipc_syscalls.c ============================================================================== --- head/sys/kern/uipc_syscalls.c Thu Oct 1 12:48:35 2009 (r197661) +++ head/sys/kern/uipc_syscalls.c Thu Oct 1 12:50:26 2009 (r197662) @@ -2086,9 +2086,11 @@ retry_space: /* * Get the page from backing store. */ - bsize = vp->v_mount->mnt_stat.f_iosize; vfslocked = VFS_LOCK_GIANT(vp->v_mount); - vn_lock(vp, LK_SHARED | LK_RETRY); + error = vn_lock(vp, LK_SHARED); + if (error != 0) + goto after_read; + bsize = vp->v_mount->mnt_stat.f_iosize; /* * XXXMAC: Because we don't have fp->f_cred @@ -2101,6 +2103,7 @@ retry_space: IO_VMIO | ((MAXBSIZE / bsize) << IO_SEQSHIFT), td->td_ucred, NOCRED, &resid, td); VOP_UNLOCK(vp, 0); + after_read: VFS_UNLOCK_GIANT(vfslocked); VM_OBJECT_LOCK(obj); vm_page_io_finish(pg);
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