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authorWei Fang <fangwei1@huawei.com>2016-06-07 14:53:56 +0800
committerMartin K. Petersen <martin.petersen@oracle.com>2016-06-08 23:08:04 -0400
commit72d8c36ec364c82bf1bf0c64dfa1041cfaf139f7 (patch)
tree4db26e920be643a2a51d97f1d3890596201c974a /drivers/scsi
parent6b7e9cde49691e04314342b7dce90c67ad567fcc (diff)
scsi: fix race between simultaneous decrements of ->host_failed
sas_ata_strategy_handler() adds the works of the ata error handler to system_unbound_wq. This workqueue asynchronously runs work items, so the ata error handler will be performed concurrently on different CPUs. In this case, ->host_failed will be decreased simultaneously in scsi_eh_finish_cmd() on different CPUs, and become abnormal. It will lead to permanently inequality between ->host_failed and ->host_busy, and scsi error handler thread won't start running. IO errors after that won't be handled. Since all scmds must have been handled in the strategy handler, just remove the decrement in scsi_eh_finish_cmd() and zero ->host_busy after the strategy handler to fix this race. Fixes: 50824d6c5657 ("[SCSI] libsas: async ata-eh") Cc: stable@vger.kernel.org Signed-off-by: Wei Fang <fangwei1@huawei.com> Reviewed-by: James Bottomley <jejb@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi')
-rw-r--r--drivers/scsi/scsi_error.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 984ddcb4786d..1b9c049bd5c5 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1127,7 +1127,6 @@ static int scsi_eh_action(struct scsi_cmnd *scmd, int rtn)
*/
void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
{
- scmd->device->host->host_failed--;
scmd->eh_eflags = 0;
list_move_tail(&scmd->eh_entry, done_q);
}
@@ -2226,6 +2225,9 @@ int scsi_error_handler(void *data)
else
scsi_unjam_host(shost);
+ /* All scmds have been handled */
+ shost->host_failed = 0;
+
/*
* Note - if the above fails completely, the action is to take
* individual devices offline and flush the queue of any