From 0809e1087c3d6f0aeb3246114a06c96bb4102274 Mon Sep 17 00:00:00 2001 From: Bob Peterson Date: Thu, 14 Nov 2019 09:49:11 -0500 Subject: [PATCH] gfs2: fix glock reference problem in gfs2_trans_remove_revoke [ Upstream commit fe5e7ba11fcf1d75af8173836309e8562aefedef ] Commit 9287c6452d2b fixed a situation in which gfs2 could use a glock after it had been freed. To do that, it temporarily added a new glock reference by calling gfs2_glock_hold in function gfs2_add_revoke. However, if the bd element was removed by gfs2_trans_remove_revoke, it failed to drop the additional reference. This patch adds logic to gfs2_trans_remove_revoke to properly drop the additional glock reference. Fixes: 9287c6452d2b ("gfs2: Fix occasional glock use-after-free") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Bob Peterson Signed-off-by: Andreas Gruenbacher Signed-off-by: Sasha Levin --- fs/gfs2/log.c | 8 ++++++++ fs/gfs2/log.h | 1 + fs/gfs2/lops.c | 5 +---- fs/gfs2/trans.c | 2 ++ 4 files changed, 12 insertions(+), 4 deletions(-) diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 90b5c8d0c56a..d3f0612e3347 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -613,6 +613,14 @@ void gfs2_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd) list_add(&bd->bd_list, &sdp->sd_log_le_revoke); } +void gfs2_glock_remove_revoke(struct gfs2_glock *gl) +{ + if (atomic_dec_return(&gl->gl_revokes) == 0) { + clear_bit(GLF_LFLUSH, &gl->gl_flags); + gfs2_glock_queue_put(gl); + } +} + void gfs2_write_revokes(struct gfs2_sbd *sdp) { struct gfs2_trans *tr; diff --git a/fs/gfs2/log.h b/fs/gfs2/log.h index 20241436126d..015766cd1f5d 100644 --- a/fs/gfs2/log.h +++ b/fs/gfs2/log.h @@ -80,6 +80,7 @@ extern void gfs2_ail1_flush(struct gfs2_sbd *sdp, struct writeback_control *wbc) extern void gfs2_log_shutdown(struct gfs2_sbd *sdp); extern int gfs2_logd(void *data); extern void gfs2_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd); +extern void gfs2_glock_remove_revoke(struct gfs2_glock *gl); extern void gfs2_write_revokes(struct gfs2_sbd *sdp); #endif /* __LOG_DOT_H__ */ diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c index 8f99b395d7bf..2b3b755ee34c 100644 --- a/fs/gfs2/lops.c +++ b/fs/gfs2/lops.c @@ -662,10 +662,7 @@ static void revoke_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr) bd = list_entry(head->next, struct gfs2_bufdata, bd_list); list_del_init(&bd->bd_list); gl = bd->bd_gl; - if (atomic_dec_return(&gl->gl_revokes) == 0) { - clear_bit(GLF_LFLUSH, &gl->gl_flags); - gfs2_glock_queue_put(gl); - } + gfs2_glock_remove_revoke(gl); kmem_cache_free(gfs2_bufdata_cachep, bd); } } diff --git a/fs/gfs2/trans.c b/fs/gfs2/trans.c index 064c9a0ef046..812b5d5978b2 100644 --- a/fs/gfs2/trans.c +++ b/fs/gfs2/trans.c @@ -266,6 +266,8 @@ void gfs2_trans_add_unrevoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len) list_del_init(&bd->bd_list); gfs2_assert_withdraw(sdp, sdp->sd_log_num_revoke); sdp->sd_log_num_revoke--; + if (bd->bd_gl) + gfs2_glock_remove_revoke(bd->bd_gl); kmem_cache_free(gfs2_bufdata_cachep, bd); tr->tr_num_revoke_rm++; if (--n == 0)