From: Daniel Wagner <dwagner@xxxxxxx> [ 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> --- drivers/scsi/qla2xxx/qla_init.c | 10 ++++++++++ drivers/scsi/qla2xxx/qla_inline.h | 5 +++++ 2 files changed, 15 insertions(+) diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c index 2861c636dd651..f17ab22ad0e4a 100644 --- a/drivers/scsi/qla2xxx/qla_init.c +++ b/drivers/scsi/qla2xxx/qla_init.c @@ -63,6 +63,16 @@ 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 1fb6ccac07ccd..26d9c78d4c52c 100644 --- a/drivers/scsi/qla2xxx/qla_inline.h +++ b/drivers/scsi/qla2xxx/qla_inline.h @@ -207,10 +207,15 @@ 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); } -- 2.25.1
