[Cluster-devel] [PATCH AUTOSEL 4.19 085/172] dlm: remove BUG() before panic()

[Cluster-devel] [PATCH AUTOSEL 4.19 085/172] dlm: remove BUG() before panic()

[Sasha Levin]

From: Arnd Bergmann <arnd@arndb.de>

[ Upstream commit fe204591cc9480347af7d2d6029b24a62e449486 ]

Building a kernel with clang sometimes fails with an objtool error in dlm:

fs/dlm/lock.o: warning: objtool: revert_lock_pc()+0xbd: can't find jump dest instruction at .text+0xd7fc

The problem is that BUG() never returns and the compiler knows
that anything after it is unreachable, however the panic still
emits some code that does not get fully eliminated.

Having both BUG() and panic() is really pointless as the BUG()
kills the current process and the subsequent panic() never hits.
In most cases, we probably don't really want either and should
replace the DLM_ASSERT() statements with WARN_ON(), as has
been done for some of them.

Remove the BUG() here so the user at least sees the panic message
and we can reliably build randconfig kernels.

Fixes: e7fd41792fc0 ("[DLM] The core of the DLM for GFS2/CLVM")
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: clang-built-linux at googlegroups.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/dlm/dlm_internal.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index 748e8d59e611..cb287df13a7a 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -99,7 +99,6 @@ do { \
                __LINE__, __FILE__, #x, jiffies); \
     {do} \
     printk("\n"); \
-    BUG(); \
     panic("DLM:  Record message above and reboot.\n"); \
   } \
 }
-- 
2.25.1

[Cluster-devel] [PATCH AUTOSEL 4.19 137/172] gfs2: Allow lock_nolock mount to specify jid=X

[Sasha Levin]

From: Bob Peterson <rpeterso@redhat.com>

[ Upstream commit ea22eee4e6027d8927099de344f7fff43c507ef9 ]

Before this patch, a simple typo accidentally added \n to the jid=
string for lock_nolock mounts. This made it impossible to mount a
gfs2 file system with a journal other than journal0. Thus:

mount -tgfs2 -o hostdata="jid=1" <device> <mount pt>

Resulted in:
mount: wrong fs type, bad option, bad superblock on <device>

In most cases this is not a problem. However, for debugging and
testing purposes we sometimes want to test the integrity of other
journals. This patch removes the unnecessary \n and thus allows
lock_nolock users to specify an alternate journal.

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/ops_fstype.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index b041cb8ae383..ed77b10bdfb5 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -903,7 +903,7 @@ static int init_per_node(struct gfs2_sbd *sdp, int undo)
 }
 
 static const match_table_t nolock_tokens = {
-	{ Opt_jid, "jid=%d\n", },
+	{ Opt_jid, "jid=%d", },
 	{ Opt_err, NULL },
 };
 
-- 
2.25.1

[Cluster-devel] [PATCH AUTOSEL 4.19 152/172] gfs2: fix use-after-free on transaction ail lists

[Sasha Levin]

From: Bob Peterson <rpeterso@redhat.com>

[ Upstream commit 83d060ca8d90fa1e3feac227f995c013100862d3 ]

Before this patch, transactions could be merged into the system
transaction by function gfs2_merge_trans(), but the transaction ail
lists were never merged. Because the ail flushing mechanism can run
separately, bd elements can be attached to the transaction's buffer
list during the transaction (trans_add_meta, etc) but quickly moved
to its ail lists. Later, in function gfs2_trans_end, the transaction
can be freed (by gfs2_trans_end) while it still has bd elements
queued to its ail lists, which can cause it to either lose track of
the bd elements altogether (memory leak) or worse, reference the bd
elements after the parent transaction has been freed.

Although I've not seen any serious consequences, the problem becomes
apparent with the previous patch's addition of:

	gfs2_assert_warn(sdp, list_empty(&tr->tr_ail1_list));

to function gfs2_trans_free().

This patch adds logic into gfs2_merge_trans() to move the merged
transaction's ail lists to the sdp transaction. This prevents the
use-after-free. To do this properly, we need to hold the ail lock,
so we pass sdp into the function instead of the transaction itself.

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/log.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index d3f0612e3347..06752db213d2 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -877,8 +877,10 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
  * @new: New transaction to be merged
  */
 
-static void gfs2_merge_trans(struct gfs2_trans *old, struct gfs2_trans *new)
+static void gfs2_merge_trans(struct gfs2_sbd *sdp, struct gfs2_trans *new)
 {
+	struct gfs2_trans *old = sdp->sd_log_tr;
+
 	WARN_ON_ONCE(!test_bit(TR_ATTACHED, &old->tr_flags));
 
 	old->tr_num_buf_new	+= new->tr_num_buf_new;
@@ -890,6 +892,11 @@ static void gfs2_merge_trans(struct gfs2_trans *old, struct gfs2_trans *new)
 
 	list_splice_tail_init(&new->tr_databuf, &old->tr_databuf);
 	list_splice_tail_init(&new->tr_buf, &old->tr_buf);
+
+	spin_lock(&sdp->sd_ail_lock);
+	list_splice_tail_init(&new->tr_ail1_list, &old->tr_ail1_list);
+	list_splice_tail_init(&new->tr_ail2_list, &old->tr_ail2_list);
+	spin_unlock(&sdp->sd_ail_lock);
 }
 
 static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
@@ -901,7 +908,7 @@ static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 	gfs2_log_lock(sdp);
 
 	if (sdp->sd_log_tr) {
-		gfs2_merge_trans(sdp->sd_log_tr, tr);
+		gfs2_merge_trans(sdp, tr);
 	} else if (tr->tr_num_buf_new || tr->tr_num_databuf_new) {
 		gfs2_assert_withdraw(sdp, test_bit(TR_ALLOCED, &tr->tr_flags));
 		sdp->sd_log_tr = tr;
-- 
2.25.1