From: Johannes Thumshirn <jthumshirn@xxxxxxx> This patch has been added to the stable tree. If you have any objections, please let us know. =============== [ Upstream commit fd3fc0b4d7305fa7246622dcc0dec69c42443f45 ] Don't crash the machine just because of an empty transfer. Use WARN_ON() combined with returning an error. Found by Dmitry Vyukov and syzkaller. [ Changed to "WARN_ON_ONCE()". Al has a patch that should fix the root cause, but a BUG_ON() is not acceptable in any case, and a WARN_ON() might still be a cause of excessive log spamming. NOTE! If this warning ever triggers, we may end up leaking resources, since this doesn't bother to try to clean the command up. So this WARN_ON_ONCE() triggering does imply real problems. But BUG_ON() is much worse. People really need to stop using BUG_ON() for "this shouldn't ever happen". It makes pretty much any bug worse. - Linus ] Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx> Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: James Bottomley <jejb@xxxxxxxxxxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxx Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> --- drivers/scsi/scsi_lib.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 17fbf1d3eadc..8ef1d5e6619a 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1119,7 +1119,8 @@ int scsi_init_io(struct scsi_cmnd *cmd) bool is_mq = (rq->mq_ctx != NULL); int error; - BUG_ON(!rq->nr_phys_segments); + if (WARN_ON_ONCE(!rq->nr_phys_segments)) + return -EINVAL; error = scsi_init_sgtable(rq, &cmd->sdb); if (error) -- 2.11.0