| From 3be8828fc507cdafe7040a3dcf361a2bcd8e305b Mon Sep 17 00:00:00 2001 |
| From: Bart Van Assche <bart.vanassche@wdc.com> |
| Date: Thu, 22 Feb 2018 11:30:20 -0800 |
| Subject: scsi: core: Avoid that ATA error handling can trigger a kernel hang or oops |
| |
| From: Bart Van Assche <bart.vanassche@wdc.com> |
| |
| commit 3be8828fc507cdafe7040a3dcf361a2bcd8e305b upstream. |
| |
| Avoid that the recently introduced call_rcu() call in the SCSI core |
| triggers a double call_rcu() call. |
| |
| Reported-by: Natanael Copa <ncopa@alpinelinux.org> |
| Reported-by: Damien Le Moal <damien.lemoal@wdc.com> |
| References: https://bugzilla.kernel.org/show_bug.cgi?id=198861 |
| Fixes: 3bd6f43f5cb3 ("scsi: core: Ensure that the SCSI error handler gets woken up") |
| Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> |
| Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> |
| Tested-by: Damien Le Moal <damien.lemoal@wdc.com> |
| Cc: Natanael Copa <ncopa@alpinelinux.org> |
| Cc: Damien Le Moal <damien.lemoal@wdc.com> |
| Cc: Alexandre Oliva <oliva@gnu.org> |
| Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> |
| Cc: Hannes Reinecke <hare@suse.com> |
| Cc: Johannes Thumshirn <jthumshirn@suse.de> |
| Cc: <stable@vger.kernel.org> |
| Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/scsi/hosts.c | 3 --- |
| drivers/scsi/scsi_error.c | 5 +++-- |
| drivers/scsi/scsi_lib.c | 2 ++ |
| include/scsi/scsi_cmnd.h | 3 +++ |
| include/scsi/scsi_host.h | 2 -- |
| 5 files changed, 8 insertions(+), 7 deletions(-) |
| |
| --- a/drivers/scsi/hosts.c |
| +++ b/drivers/scsi/hosts.c |
| @@ -328,8 +328,6 @@ static void scsi_host_dev_release(struct |
| if (shost->work_q) |
| destroy_workqueue(shost->work_q); |
| |
| - destroy_rcu_head(&shost->rcu); |
| - |
| if (shost->shost_state == SHOST_CREATED) { |
| /* |
| * Free the shost_dev device name here if scsi_host_alloc() |
| @@ -404,7 +402,6 @@ struct Scsi_Host *scsi_host_alloc(struct |
| INIT_LIST_HEAD(&shost->starved_list); |
| init_waitqueue_head(&shost->host_wait); |
| mutex_init(&shost->scan_mutex); |
| - init_rcu_head(&shost->rcu); |
| |
| index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL); |
| if (index < 0) |
| --- a/drivers/scsi/scsi_error.c |
| +++ b/drivers/scsi/scsi_error.c |
| @@ -222,7 +222,8 @@ static void scsi_eh_reset(struct scsi_cm |
| |
| static void scsi_eh_inc_host_failed(struct rcu_head *head) |
| { |
| - struct Scsi_Host *shost = container_of(head, typeof(*shost), rcu); |
| + struct scsi_cmnd *scmd = container_of(head, typeof(*scmd), rcu); |
| + struct Scsi_Host *shost = scmd->device->host; |
| unsigned long flags; |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| @@ -258,7 +259,7 @@ void scsi_eh_scmd_add(struct scsi_cmnd * |
| * Ensure that all tasks observe the host state change before the |
| * host_failed change. |
| */ |
| - call_rcu(&shost->rcu, scsi_eh_inc_host_failed); |
| + call_rcu(&scmd->rcu, scsi_eh_inc_host_failed); |
| } |
| |
| /** |
| --- a/drivers/scsi/scsi_lib.c |
| +++ b/drivers/scsi/scsi_lib.c |
| @@ -670,6 +670,7 @@ static bool scsi_end_request(struct requ |
| if (!blk_rq_is_scsi(req)) { |
| WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED)); |
| cmd->flags &= ~SCMD_INITIALIZED; |
| + destroy_rcu_head(&cmd->rcu); |
| } |
| |
| if (req->mq_ctx) { |
| @@ -1150,6 +1151,7 @@ void scsi_initialize_rq(struct request * |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); |
| |
| scsi_req_init(&cmd->req); |
| + init_rcu_head(&cmd->rcu); |
| cmd->jiffies_at_alloc = jiffies; |
| cmd->retries = 0; |
| } |
| --- a/include/scsi/scsi_cmnd.h |
| +++ b/include/scsi/scsi_cmnd.h |
| @@ -69,6 +69,9 @@ struct scsi_cmnd { |
| struct list_head list; /* scsi_cmnd participates in queue lists */ |
| struct list_head eh_entry; /* entry for the host eh_cmd_q */ |
| struct delayed_work abort_work; |
| + |
| + struct rcu_head rcu; |
| + |
| int eh_eflags; /* Used by error handlr */ |
| |
| /* |
| --- a/include/scsi/scsi_host.h |
| +++ b/include/scsi/scsi_host.h |
| @@ -571,8 +571,6 @@ struct Scsi_Host { |
| struct blk_mq_tag_set tag_set; |
| }; |
| |
| - struct rcu_head rcu; |
| - |
| atomic_t host_busy; /* commands actually active on low-level */ |
| atomic_t host_blocked; |
| |