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authorBob Peterson <rpeterso@redhat.com>2019-11-14 17:49:11 +0300
committerAndreas Gruenbacher <agruenba@redhat.com>2019-11-14 18:51:00 +0300
commitfe5e7ba11fcf1d75af8173836309e8562aefedef (patch)
treec10085dc5073f46c1472d98d12106f7e21dc523d /fs/gfs2
parentfeed98a8e5f3e54a8c41a3b26aa914db5d7e3c18 (diff)
downloadlinux-fe5e7ba11fcf1d75af8173836309e8562aefedef.tar.xz
gfs2: fix glock reference problem in gfs2_trans_remove_revoke
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 <rpeterso@redhat.com> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Diffstat (limited to 'fs/gfs2')
-rw-r--r--fs/gfs2/log.c8
-rw-r--r--fs/gfs2/log.h1
-rw-r--r--fs/gfs2/lops.c5
-rw-r--r--fs/gfs2/trans.c2
4 files changed, 12 insertions, 4 deletions
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 4a7713c62f04..68af71eb28c6 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -611,6 +611,14 @@ void gfs2_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
list_add(&bd->bd_list, &sdp->sd_log_revokes);
}
+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 2421181dbfb9..2ff163a8dce1 100644
--- a/fs/gfs2/log.h
+++ b/fs/gfs2/log.h
@@ -76,6 +76,7 @@ extern void gfs2_ail1_flush(struct gfs2_sbd *sdp, struct writeback_control *wbc)
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 313b83ef6657..55fed7daf2b1 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -883,10 +883,7 @@ 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 35e3059255fe..9d4227330de4 100644
--- a/fs/gfs2/trans.c
+++ b/fs/gfs2/trans.c
@@ -262,6 +262,8 @@ void gfs2_trans_remove_revoke(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--;
if (--n == 0)