From 5259a06ef97068b710f45d092a587e8d740f750f Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Tue, 28 Jan 2014 17:56:30 -0800 Subject: target: Fix percpu_ref_put race in transport_lun_remove_cmd This patch fixes a percpu_ref_put race for se_lun->lun_ref in transport_lun_remove_cmd() where ->lun_ref could end up being put more than once per command via different target completion and fabric release contexts. It adds a cmpxchg() for se_cmd->lun_ref_active to ensure that percpu_ref_put() is only ever called once per se_cmd. This bug was manifesting itself as a LUN shutdown regression bug in >= v3.13 code, where percpu_ref_kill() would end up hanging indefinately due to the incorrect percpu_ref count. (Change se_cmd->lun_ref_active from bool -> int to force at least a 4-byte cmpxchg with MIPS ll/sc ins. - Fengguang) Reported-by: Tommy Apel Cc: Tommy Apel Cc: #3.13+ Signed-off-by: Nicholas Bellinger --- include/target/target_core_base.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/target') diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index d28418645b00..909dacbd230f 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -552,7 +552,7 @@ struct se_cmd { void *priv; /* Used for lun->lun_ref counting */ - bool lun_ref_active; + int lun_ref_active; /* DIF related members */ enum target_prot_op prot_op; -- cgit v1.2.3-59-g8ed1b