Date: Sun, 24 Sep 2023 21:47:02 GMT From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: aaeaba324335 - releng/14.0 - vfs: fix reference counting/locking on LK_UPGRADE error Message-ID: <202309242147.38OLl2iv031000@gitrepo.freebsd.org>
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The branch releng/14.0 has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=aaeaba3243354f02a7a7c4ff519efd88edc22572 commit aaeaba3243354f02a7a7c4ff519efd88edc22572 Author: Olivier Certner <olce.freebsd@certner.fr> AuthorDate: 2023-09-22 20:57:20 +0000 Commit: Mateusz Guzik <mjg@FreeBSD.org> CommitDate: 2023-09-24 21:46:25 +0000 vfs: fix reference counting/locking on LK_UPGRADE error Factoring out this code unfortunately introduced reference and lock leaks in case of failure in the lock upgrade path under VV_CROSSLOCK. In terms of practical use, this impacts unionfs (and nullfs in a corner case). Fixes: 80bd5ef07025 ("vfs: factor out mount point traversal to a dedicated routine") MFC after: 3 days MFC to: stable/14 releng/14.0 Sponsored by: The FreeBSD Foundation Reviewed by: mjg [mjg: massaged the commit message a little bit] Differential Revision: https://reviews.freebsd.org/D41731 Approved by: re (gjb) (cherry picked from commit 02cbc029dac936b4ddbc38cef969c4b30c9a7d1f) (cherry picked from commit c76dfb929e70c80a2d0280a1371c07738d910c11) --- sys/kern/vfs_lookup.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/sys/kern/vfs_lookup.c b/sys/kern/vfs_lookup.c index 151253ffa0f5..d75351c34314 100644 --- a/sys/kern/vfs_lookup.c +++ b/sys/kern/vfs_lookup.c @@ -905,8 +905,15 @@ vfs_lookup_cross_mount(struct nameidata *ndp) crosslkflags |= LK_EXCLUSIVE | LK_CANRECURSE; } else if ((crosslkflags & LK_EXCLUSIVE) != 0) { error = vn_lock(dp, LK_UPGRADE); - if (error != 0) + if (error != 0) { + MPASS(error == ENOENT); + vrele(dp); + if (dp != ndp->ni_dvp) + vput(ndp->ni_dvp); + else + vrele(ndp->ni_dvp); break; + } if (dp->v_mountedhere != mp) { continue; }
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