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authorBob Peterson <rpeterso@redhat.com>2021-03-12 07:58:54 -0500
committerAndreas Gruenbacher <agruenba@redhat.com>2021-03-12 14:55:23 +0100
commitd5bf630f355d8c532bef2347cf90e8ae60a5f1bd (patch)
treecb7cdc1c95c123fa07ded5b6f017cf68a70f53be /fs/gfs2
parent1a5a2cfd34c17db73c53ef127272c8c1ae220485 (diff)
downloadlinux-d5bf630f355d8c532bef2347cf90e8ae60a5f1bd.tar.gz
gfs2: bypass signal_our_withdraw if no journal
Before this patch, function signal_our_withdraw referenced the journal
inode immediately. But corrupt file systems may have some invalid
journals, in which case our attempt to read it in will withdraw and the
resulting signal_our_withdraw would dereference the NULL value.

This patch adds a check to signal_our_withdraw so that if the journal
has not yet been initialized, it simply returns and does the old-style
withdraw.

Thanks, Andy Price, for his analysis.

Reported-by: syzbot+50a8a9cf8127f2c6f5df@syzkaller.appspotmail.com
Fixes: 601ef0d52e96 ("gfs2: Force withdraw to replay journals and wait for it to finish")
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Diffstat (limited to 'fs/gfs2')
-rw-r--r--fs/gfs2/util.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/fs/gfs2/util.c b/fs/gfs2/util.c
index 58743315cda9..4f034b87b427 100644
--- a/fs/gfs2/util.c
+++ b/fs/gfs2/util.c
@@ -119,17 +119,22 @@ void gfs2_freeze_unlock(struct gfs2_holder *freeze_gh)
 static void signal_our_withdraw(struct gfs2_sbd *sdp)
 {
 	struct gfs2_glock *live_gl = sdp->sd_live_gh.gh_gl;
-	struct inode *inode = sdp->sd_jdesc->jd_inode;
-	struct gfs2_inode *ip = GFS2_I(inode);
-	struct gfs2_glock *i_gl = ip->i_gl;
-	u64 no_formal_ino = ip->i_no_formal_ino;
+	struct inode *inode;
+	struct gfs2_inode *ip;
+	struct gfs2_glock *i_gl;
+	u64 no_formal_ino;
 	int log_write_allowed = test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
 	int ret = 0;
 	int tries;
 
-	if (test_bit(SDF_NORECOVERY, &sdp->sd_flags))
+	if (test_bit(SDF_NORECOVERY, &sdp->sd_flags) || !sdp->sd_jdesc)
 		return;
 
+	inode = sdp->sd_jdesc->jd_inode;
+	ip = GFS2_I(inode);
+	i_gl = ip->i_gl;
+	no_formal_ino = ip->i_no_formal_ino;
+
 	/* Prevent any glock dq until withdraw recovery is complete */
 	set_bit(SDF_WITHDRAW_RECOVERY, &sdp->sd_flags);
 	/*