This is a note to let you know that I've just added the patch titled scsi: qla2xxx: Warn if done() or free() are called on an already freed srb to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: scsi-qla2xxx-warn-if-done-or-free-are-called-on-an-a.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit fc75702aa7ccf922451c8b4e920fe5533de960b5 Author: Daniel Wagner <dwagner@xxxxxxx> Date: Tue Sep 8 10:15:13 2020 +0200 scsi: qla2xxx: Warn if done() or free() are called on an already freed srb [ Upstream commit c0014f94218ea3a312f6235febea0d626c5f2154 ] Emit a warning when ->done or ->free are called on an already freed srb. There is a hidden use-after-free bug in the driver which corrupts the srb memory pool which originates from the cleanup callbacks. An extensive search didn't bring any lights on the real problem. The initial fix was to set both pointers to NULL and try to catch invalid accesses. But instead the memory corruption was gone and the driver didn't crash. Since not all calling places check for NULL pointer, add explicitly default handlers. With this we workaround the memory corruption and add a debug help. Link: https://lore.kernel.org/r/20200908081516.8561-2-dwagner@xxxxxxx Reviewed-by: Martin Wilck <mwilck@xxxxxxxx> Reviewed-by: Arun Easi <aeasi@xxxxxxxxxxx> Signed-off-by: Daniel Wagner <dwagner@xxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c index 62d2ee825c97a..b300e11095828 100644 --- a/drivers/scsi/qla2xxx/qla_init.c +++ b/drivers/scsi/qla2xxx/qla_init.c @@ -71,6 +71,16 @@ void qla2x00_sp_free(srb_t *sp) qla2x00_rel_sp(sp); } +void qla2xxx_rel_done_warning(srb_t *sp, int res) +{ + WARN_ONCE(1, "Calling done() of an already freed srb %p object\n", sp); +} + +void qla2xxx_rel_free_warning(srb_t *sp) +{ + WARN_ONCE(1, "Calling free() of an already freed srb %p object\n", sp); +} + /* Asynchronous Login/Logout Routines -------------------------------------- */ unsigned long diff --git a/drivers/scsi/qla2xxx/qla_inline.h b/drivers/scsi/qla2xxx/qla_inline.h index 0c3d907af7692..6dfde42d799b5 100644 --- a/drivers/scsi/qla2xxx/qla_inline.h +++ b/drivers/scsi/qla2xxx/qla_inline.h @@ -183,10 +183,15 @@ qla2xxx_get_qpair_sp(scsi_qla_host_t *vha, struct qla_qpair *qpair, return sp; } +void qla2xxx_rel_done_warning(srb_t *sp, int res); +void qla2xxx_rel_free_warning(srb_t *sp); + static inline void qla2xxx_rel_qpair_sp(struct qla_qpair *qpair, srb_t *sp) { sp->qpair = NULL; + sp->done = qla2xxx_rel_done_warning; + sp->free = qla2xxx_rel_free_warning; mempool_free(sp, qpair->srb_mempool); QLA_QPAIR_MARK_NOT_BUSY(qpair); }