gfs2_log_release_revokes states in its function documentation that sdp->sd_log_flush_lock must be held. The operations on sd_log_revokes_available are always protected under that lock. All callers except gfs2_trans_remove_revoke hold the lock. Acquire that lock in gfs2_trans_remove_revoke. The other callsites use a read lock as well.
This bug was found using my experimental own-developed static analysis tool, which reported the missing lock on v6.0-rc5. I manually verified this bug report by doing code review as well. I compile tested and runtime checked that the required lock is not held on a x86-64 config. After applying this patch, my analyser no longer reports this potential bug. Fixes: 2129b4288852 ("gfs2: Per-revoke accounting in transactions") Signed-off-by: Niels Dossche <dossche.ni...@gmail.com> --- fs/gfs2/trans.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/gfs2/trans.c b/fs/gfs2/trans.c index 63fec11ef2ce..468e4da20a44 100644 --- a/fs/gfs2/trans.c +++ b/fs/gfs2/trans.c @@ -301,6 +301,7 @@ void gfs2_trans_remove_revoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len) struct gfs2_bufdata *bd, *tmp; unsigned int n = len; + down_read(&sdp->sd_log_flush_lock); gfs2_log_lock(sdp); list_for_each_entry_safe(bd, tmp, &sdp->sd_log_revokes, bd_list) { if ((bd->bd_blkno >= blkno) && (bd->bd_blkno < (blkno + len))) { @@ -316,6 +317,7 @@ void gfs2_trans_remove_revoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len) } } gfs2_log_unlock(sdp); + up_read(&sdp->sd_log_flush_lock); } void gfs2_trans_free(struct gfs2_sbd *sdp, struct gfs2_trans *tr) -- 2.37.3