From: Darrick J. Wong <djwong@kernel.org>
Date: Fri, 15 Oct 2021 20:28:14 +0000 (-0400)
Subject: libxfs: fix crash on second attempt to initialize library
X-Git-Tag: libxfs-5.14-sync_2021-10-16~53
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c1ab394af3c6e51f14ca04bf7d2a2881d3c55daf;p=thirdparty%2Fxfsprogs-dev.git

libxfs: fix crash on second attempt to initialize library

xfs_repair crashes when it tries to initialize the libxfs library but
the initialization fails because the fs is already mounted:

# xfs_repair /dev/sdd
xfs_repair: /dev/sdd contains a mounted filesystem
xfs_repair: urcu.c:553: urcu_memb_register_thread: Assertion `!URCU_TLS(rcu_reader).registered' failed.
Aborted

This is because libxfs_init() registers the main thread with liburcu,
but doesn't unregister the thread if libxfs library initialization
fails.  When repair sets more dangerous options and tries again, the
second initialization attempt causes liburcu to abort.  Fix this by
unregistering the thread with liburcu if libxfs initialization fails.

Observed by running xfs/284.

Fixes: e4da1b16 ("xfsprogs: introduce liburcu support")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
---

diff --git a/libxfs/init.c b/libxfs/init.c
index d0753ce5e..14911596c 100644
--- a/libxfs/init.c
+++ b/libxfs/init.c
@@ -407,8 +407,10 @@ done:
 		unlink(rtpath);
 	if (fd >= 0)
 		close(fd);
-	if (!rval)
+	if (!rval) {
 		libxfs_close_devices(a);
+		rcu_unregister_thread();
+	}
 
 	return rval;
 }