From: Iago Abal <mail@xxxxxxxxxxx> The EBA code analyzer (https://github.com/models-team/eba) reported the following double lock: 1. In function `megaraid_reset_handler' at 2571; 2. take `&adapter->pend_list_lock' for the first time at 2602: // FIRST spin_lock_irqsave(PENDING_LIST_LOCK(adapter), flags); 3. enter the `list_for_each_entry_safe' loop at 2603; 4. call `megaraid_mbox_mm_done' at 2616; 5. call `megaraid_mbox_runpendq' at 3782; 6. take `&adapter->pend_list_lock' for the second time at 1892: // SECOND: DOUBLE LOCK !!! spin_lock_irqsave(PENDING_LIST_LOCK(adapter), flags); >From my shallow understanding of the code (so please review carefully), I think that it is not necessary to hold `PENDING_LIST_LOCK(adapter)' while executing the body of the `list_for_each_entry_safe' loop. I assume this because both `megaraid_mbox_mm_done' and `megaraid_dealloc_scb' are called from several places where, as far as I can tell, this lock is not hold. In fact, as reported by EBA, at some point `megaraid_mbox_mm_done' will acquire this lock again. Fixes: c005fb4fb2d2 ("[SCSI] megaraid_{mm,mbox}: fix a bug in reset handler") Signed-off-by: Iago Abal <mail@xxxxxxxxxxx> --- drivers/scsi/megaraid/megaraid_mbox.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/scsi/megaraid/megaraid_mbox.c b/drivers/scsi/megaraid/megaraid_mbox.c index f0987f2..7f11898 100644 --- a/drivers/scsi/megaraid/megaraid_mbox.c +++ b/drivers/scsi/megaraid/megaraid_mbox.c @@ -2603,6 +2603,7 @@ static DEF_SCSI_QCMD(megaraid_queue_command) list_for_each_entry_safe(scb, tmp, &adapter->pend_list, list) { list_del_init(&scb->list); // from pending list + spin_unlock_irqrestore(PENDING_LIST_LOCK(adapter), flags); if (scb->sno >= MBOX_MAX_SCSI_CMDS) { con_log(CL_ANN, (KERN_WARNING "megaraid: IOCTL packet with %d[%d:%d] being reset\n", @@ -2630,6 +2631,7 @@ static DEF_SCSI_QCMD(megaraid_queue_command) megaraid_dealloc_scb(adapter, scb); } + spin_lock_irqsave(PENDING_LIST_LOCK(adapter), flags); } spin_unlock_irqrestore(PENDING_LIST_LOCK(adapter), flags); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
