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authorDaniel Jordan2020-06-08 17:26:52 -0400
committerHerbert Xu2020-06-18 17:09:54 +1000
commite04ec0de61c1eb9693179093e83ab8ca68a30d08 (patch)
treec9659db2092a276ee7a64922be0c57e0526f4c07
parent34c86f4c4a7be3b3e35aa48bd18299d4c756064d (diff)
padata: upgrade smp_mb__after_atomic to smp_mb in padata_do_serial
A 5.7 kernel hangs during a tcrypt test of padata that waits for an AEAD request to finish. This is only seen on large machines running many concurrent requests. The issue is that padata never serializes the request. The removal of the reorder_objects atomic missed that the memory barrier in padata_do_serial() depends on it. Upgrade the barrier from smp_mb__after_atomic to smp_mb to get correct ordering again. Fixes: 3facced7aeed1 ("padata: remove reorder_objects") Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: linux-kernel@vger.kernel.org Cc: <stable@vger.kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--kernel/padata.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/padata.c b/kernel/padata.c
index 29fc5d87a4cd..4373f7adaa40 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -335,7 +335,7 @@ static void padata_reorder(struct parallel_data *pd)
*
* Ensure reorder queue is read after pd->lock is dropped so we see
* new objects from another task in padata_do_serial. Pairs with
- * smp_mb__after_atomic in padata_do_serial.
+ * smp_mb in padata_do_serial.
*/
smp_mb();
@@ -418,7 +418,7 @@ void padata_do_serial(struct padata_priv *padata)
* with the trylock of pd->lock in padata_reorder. Pairs with smp_mb
* in padata_reorder.
*/
- smp_mb__after_atomic();
+ smp_mb();
padata_reorder(pd);
}