Date: Wed, 21 May 2003 23:20:49 -0700 (PDT) From: Don Lewis <truckman@FreeBSD.org> To: des@FreeBSD.org, jeff@FreeBSD.org Cc: current@FreeBSD.org Subject: possible patch for vnode double unlock in pfs_lookup() Message-ID: <200305220620.h4M6KnM7075096@gw.catspoiler.org>
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If the ISDOTDOT flag is set and the lockparent or ISLASTCN flags are not set, pfs_lookup() unlocks the same vnode twice. This can be observed by running find / -print with the DEBUG_VFS_LOCKS kernel option enabled. I think the following is the correct patch: I believe that it is safe to defer committing a fix until after 5.1-RELEASE. Index: sys/fs/pseudofs/pseudofs_vnops.c =================================================================== RCS file: /home/ncvs/src/sys/fs/pseudofs/pseudofs_vnops.c,v retrieving revision 1.35 diff -u -r1.35 pseudofs_vnops.c --- sys/fs/pseudofs/pseudofs_vnops.c 2 Mar 2003 22:23:45 -0000 1.35 +++ sys/fs/pseudofs/pseudofs_vnops.c 22 May 2003 04:40:09 -0000 @@ -411,7 +411,8 @@ vn_lock(vn, LK_EXCLUSIVE|LK_RETRY, cnp->cn_thread); cnp->cn_flags &= ~PDIRUNLOCK; } - if (!lockparent || !(cnp->cn_flags & ISLASTCN)) + if ((!lockparent || !(cnp->cn_flags & ISLASTCN)) && + !(cnp->cn_flags & ISDOTDOT)) VOP_UNLOCK(vn, 0, cnp->cn_thread); /*
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