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| author | Johannes Thumshirn <jthumshirn@suse.de> | 2017-01-31 10:16:00 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-19 09:49:15 -0800 |
| commit | fd3fc0b4d7305fa7246622dcc0dec69c42443f45 (patch) | |
| tree | f66560ae05fd7b68c20b687d4f08981eb810ab80 | |
| parent | 00ea1ceebe0d9f2dc1cc2b7bd575a00100c27869 (diff) | |
| download | linux-stable-fd3fc0b4d7305fa7246622dcc0dec69c42443f45.tar.gz linux-stable-fd3fc0b4d7305fa7246622dcc0dec69c42443f45.tar.bz2 linux-stable-fd3fc0b4d7305fa7246622dcc0dec69c42443f45.zip | |
scsi: don't BUG_ON() empty DMA transfers
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@suse.de>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: James Bottomley <jejb@linux.vnet.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/scsi/scsi_lib.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index e9e1e141af9c..78db07fd8055 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1040,7 +1040,8 @@ int scsi_init_io(struct scsi_cmnd *cmd) bool is_mq = (rq->mq_ctx != NULL); int error; - BUG_ON(!blk_rq_nr_phys_segments(rq)); + if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq))) + return -EINVAL; error = scsi_init_sgtable(rq, &cmd->sdb); if (error) |