From: Bob Peterson rpeterso@redhat.com
[ Upstream commit d5bf630f355d8c532bef2347cf90e8ae60a5f1bd ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/gfs2/util.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/fs/gfs2/util.c b/fs/gfs2/util.c index a1ecb2b48250..3ece99e6490c 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); /*