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authorEric Biggers <ebiggers@google.com>2018-02-03 20:33:27 -0800
committerTejun Heo <tj@kernel.org>2018-02-12 09:20:34 -0800
commit9173e5e80729c8434b8d27531527c5245f4a5594 (patch)
tree9dba5add9e00e037b6f052dedc770662b9576b59
parent058f58e235cbe03e923b30ea7c49995a46a8725f (diff)
libata: remove WARN() for DMA or PIO command without data
syzkaller hit a WARN() in ata_qc_issue() when writing to /dev/sg0. This happened because it issued a READ_6 command with no data buffer. Just remove the WARN(), as it doesn't appear indicate a kernel bug. The expected behavior is to fail the command, which the code does. Here's a reproducer that works in QEMU when /dev/sg0 refers to a disk of the default type ("82371SB PIIX3 IDE"): #include <fcntl.h> #include <unistd.h> int main() { char buf[42] = { [36] = 0x8 /* READ_6 */ }; write(open("/dev/sg0", O_RDWR), buf, sizeof(buf)); } Fixes: f92a26365a72 ("libata: change ATA_QCFLAG_DMAMAP semantics") Reported-by: syzbot+f7b556d1766502a69d85071d2ff08bd87be53d0f@syzkaller.appspotmail.com Cc: <stable@vger.kernel.org> # v2.6.25+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
-rw-r--r--drivers/ata/libata-core.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 3c09122bf038..61b09968d032 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5401,8 +5401,7 @@ void ata_qc_issue(struct ata_queued_cmd *qc)
* We guarantee to LLDs that they will have at least one
* non-zero sg if the command is a data command.
*/
- if (WARN_ON_ONCE(ata_is_data(prot) &&
- (!qc->sg || !qc->n_elem || !qc->nbytes)))
+ if (ata_is_data(prot) && (!qc->sg || !qc->n_elem || !qc->nbytes))
goto sys_err;
if (ata_is_dma(prot) || (ata_is_pio(prot) &&