diff options
| author | Eric Biggers <ebiggers@google.com> | 2018-02-04 07:33:27 +0300 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2018-02-12 20:20:34 +0300 |
| commit | 9173e5e80729c8434b8d27531527c5245f4a5594 (patch) | |
| tree | 9dba5add9e00e037b6f052dedc770662b9576b59 | |
| parent | 058f58e235cbe03e923b30ea7c49995a46a8725f (diff) | |
| download | linux-9173e5e80729c8434b8d27531527c5245f4a5594.tar.xz | |
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.c | 3 |
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) && |