Hello,
syzbot found the following crash on:
HEAD commit: 1e76a3e5 kmsan: replace __GFP_NO_KMSAN_SHADOW with kmsan_i..
git tree: https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=16860a63600000
kernel config: https://syzkaller.appspot.com/x/.config?x=f03c659d0830ab8d
dashboard link: https://syzkaller.appspot.com/bug?extid=6bf9606ee955b646c0e1
compiler: clang version 9.0.0 (/home/glider/llvm/clang
80fee25776c2fb61e74c1ecb1a523375c2500b69)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12c1101b600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15db3cfd600000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email protected]
dvb-usb: schedule remote query interval to 1000 msecs.
dvb-usb: Nebula Electronics uDigiTV DVB-T USB2.0) successfully initialized
and connected.
dvb-usb: bulk message failed: -22 (7/0)
dvb-usb: bulk message failed: -22 (7/0)
dvb-usb: bulk message failed: -22 (7/-30591)
dvb-usb: bulk message failed: -22 (7/0)
=====================================================
BUG: KMSAN: uninit-value in legacy_dvb_usb_read_remote_control+0x106/0x790
drivers/media/usb/dvb-usb/dvb-usb-remote.c:123
CPU: 1 PID: 3844 Comm: kworker/1:2 Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: events legacy_dvb_usb_read_remote_control
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x191/0x1f0 lib/dump_stack.c:113
kmsan_report+0x13a/0x2b0 mm/kmsan/kmsan_report.c:108
__msan_warning+0x73/0xe0 mm/kmsan/kmsan_instr.c:250
digitv_rc_query+0x76a/0x890 drivers/media/usb/dvb-usb/digitv.c:259
legacy_dvb_usb_read_remote_control+0x106/0x790
drivers/media/usb/dvb-usb/dvb-usb-remote.c:123
process_one_work+0x1572/0x1ef0 kernel/workqueue.c:2269
worker_thread+0x111b/0x2460 kernel/workqueue.c:2415
kthread+0x4b5/0x4f0 kernel/kthread.c:256
ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355
Local variable description: ----key@digitv_rc_query
Variable was created at:
digitv_rc_query+0x78/0x890 drivers/media/usb/dvb-usb/digitv.c:234
legacy_dvb_usb_read_remote_control+0x106/0x790
drivers/media/usb/dvb-usb/dvb-usb-remote.c:123
=====================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 3844 Comm: kworker/1:2 Tainted: G B 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: events legacy_dvb_usb_read_remote_control
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x191/0x1f0 lib/dump_stack.c:113
panic+0x3c9/0xc1e kernel/panic.c:219
kmsan_report+0x2a2/0x2b0 mm/kmsan/kmsan_report.c:131
__msan_warning+0x73/0xe0 mm/kmsan/kmsan_instr.c:250
digitv_rc_query+0x76a/0x890 drivers/media/usb/dvb-usb/digitv.c:259
legacy_dvb_usb_read_remote_control+0x106/0x790
drivers/media/usb/dvb-usb/dvb-usb-remote.c:123
process_one_work+0x1572/0x1ef0 kernel/workqueue.c:2269
worker_thread+0x111b/0x2460 kernel/workqueue.c:2415
kthread+0x4b5/0x4f0 kernel/kthread.c:256
ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355
Kernel Offset: disabled
Rebooting in 86400 seconds..
---
This bug is generated by a bot. It may contain errors.
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syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches
For fixing syzbot "KMSAN: uninit-value in digitv_rc_query"
In scenario testing for syzbot, failure reading from
digitv_ctrl_msg() [1].
Eg:
[ 91.846657][ T3844] dvb-usb: bulk message failed: -22 (7/0)
digitv_rc_query() always return 0. But in this case a wrong thing happens.
Reported-by: [email protected]
Tested-by: [email protected]
[1]: https://syzkaller.appspot.com/text?tag=CrashLog&x=16860a63600000
[2]: https://groups.google.com/d/msg/syzkaller-bugs/-TXIJAZ0J9Q/T4PEUQoeAQAJ
Signed-off-by: Phong Tran <[email protected]>
---
drivers/media/usb/dvb-usb/digitv.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/media/usb/dvb-usb/digitv.c b/drivers/media/usb/dvb-usb/digitv.c
index dd5bb230cec1..61bc8945e6b9 100644
--- a/drivers/media/usb/dvb-usb/digitv.c
+++ b/drivers/media/usb/dvb-usb/digitv.c
@@ -231,17 +231,21 @@ static struct rc_map_table rc_map_digitv_table[] = {
static int digitv_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
{
int i;
- u8 key[5];
+ u8 key[5] = { 0 };
u8 b[4] = { 0 };
+ int ret;
*event = 0;
*state = REMOTE_NO_KEY_PRESSED;
- digitv_ctrl_msg(d,USB_READ_REMOTE,0,NULL,0,&key[1],4);
-
+ ret = digitv_ctrl_msg(d, USB_READ_REMOTE, 0, NULL, 0, &key[1], 4);
+ if (ret < 0)
+ return ret;
/* Tell the device we've read the remote. Not sure how necessary
this is, but the Nebula SDK does it. */
- digitv_ctrl_msg(d,USB_WRITE_REMOTE,0,b,4,NULL,0);
+ ret = digitv_ctrl_msg(d, USB_WRITE_REMOTE, 0, b, 4, NULL, 0);
+ if (ret < 0)
+ return ret;
/* if something is inside the buffer, simulate key press */
if (key[1] != 0)
--
2.20.1
Hello,
On Tue, Dec 03, 2019 at 07:41:38AM +0700, Phong Tran wrote:
> For fixing syzbot "KMSAN: uninit-value in digitv_rc_query"
>
> In scenario testing for syzbot, failure reading from
> digitv_ctrl_msg() [1].
>
> Eg:
> [ 91.846657][ T3844] dvb-usb: bulk message failed: -22 (7/0)
>
> digitv_rc_query() always return 0. But in this case a wrong thing happens.
>
> Reported-by: [email protected]
> Tested-by: [email protected]
A fix for this was already merged I'm afraid, see commit eecc70d22ae5
("media: digitv: don't continue if remote control state can't be read").
> [1]: https://syzkaller.appspot.com/text?tag=CrashLog&x=16860a63600000
> [2]: https://groups.google.com/d/msg/syzkaller-bugs/-TXIJAZ0J9Q/T4PEUQoeAQAJ
>
> Signed-off-by: Phong Tran <[email protected]>
> ---
> drivers/media/usb/dvb-usb/digitv.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/usb/dvb-usb/digitv.c b/drivers/media/usb/dvb-usb/digitv.c
> index dd5bb230cec1..61bc8945e6b9 100644
> --- a/drivers/media/usb/dvb-usb/digitv.c
> +++ b/drivers/media/usb/dvb-usb/digitv.c
> @@ -231,17 +231,21 @@ static struct rc_map_table rc_map_digitv_table[] = {
> static int digitv_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
> {
> int i;
> - u8 key[5];
> + u8 key[5] = { 0 };
The merged commit does not change this line. Why was this changed?
Thanks
Sean
> u8 b[4] = { 0 };
> + int ret;
>
> *event = 0;
> *state = REMOTE_NO_KEY_PRESSED;
>
> - digitv_ctrl_msg(d,USB_READ_REMOTE,0,NULL,0,&key[1],4);
> -
> + ret = digitv_ctrl_msg(d, USB_READ_REMOTE, 0, NULL, 0, &key[1], 4);
> + if (ret < 0)
> + return ret;
> /* Tell the device we've read the remote. Not sure how necessary
> this is, but the Nebula SDK does it. */
> - digitv_ctrl_msg(d,USB_WRITE_REMOTE,0,b,4,NULL,0);
> + ret = digitv_ctrl_msg(d, USB_WRITE_REMOTE, 0, b, 4, NULL, 0);
> + if (ret < 0)
> + return ret;
>
> /* if something is inside the buffer, simulate key press */
> if (key[1] != 0)
> --
> 2.20.1
On Wed, Jan 15, 2020 at 05:32:26PM +0000, Sean Young wrote:
> Hello,
>
> On Tue, Dec 03, 2019 at 07:41:38AM +0700, Phong Tran wrote:
> > For fixing syzbot "KMSAN: uninit-value in digitv_rc_query"
> >
> > In scenario testing for syzbot, failure reading from
> > digitv_ctrl_msg() [1].
> >
> > Eg:
> > [ 91.846657][ T3844] dvb-usb: bulk message failed: -22 (7/0)
> >
> > digitv_rc_query() always return 0. But in this case a wrong thing happens.
> >
> > Reported-by: [email protected]
> > Tested-by: [email protected]
>
> A fix for this was already merged I'm afraid, see commit eecc70d22ae5
> ("media: digitv: don't continue if remote control state can't be read").
>
> > [1]: https://syzkaller.appspot.com/text?tag=CrashLog&x=16860a63600000
> > [2]: https://groups.google.com/d/msg/syzkaller-bugs/-TXIJAZ0J9Q/T4PEUQoeAQAJ
> >
> > Signed-off-by: Phong Tran <[email protected]>
> > ---
> > drivers/media/usb/dvb-usb/digitv.c | 12 ++++++++----
> > 1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/media/usb/dvb-usb/digitv.c b/drivers/media/usb/dvb-usb/digitv.c
> > index dd5bb230cec1..61bc8945e6b9 100644
> > --- a/drivers/media/usb/dvb-usb/digitv.c
> > +++ b/drivers/media/usb/dvb-usb/digitv.c
> > @@ -231,17 +231,21 @@ static struct rc_map_table rc_map_digitv_table[] = {
> > static int digitv_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
> > {
> > int i;
> > - u8 key[5];
> > + u8 key[5] = { 0 };
>
> The merged commit does not change this line. Why was this changed?
>
It would fix the problem that key[0] is never initialized... But the
correct fix is to make key 4 elements long and delete key[0].
regards,
dan carpenter
On Wed, Jan 15, 2020 at 09:01:17PM +0300, Dan Carpenter wrote:
> On Wed, Jan 15, 2020 at 05:32:26PM +0000, Sean Young wrote:
> > Hello,
> >
> > On Tue, Dec 03, 2019 at 07:41:38AM +0700, Phong Tran wrote:
> > > For fixing syzbot "KMSAN: uninit-value in digitv_rc_query"
> > >
> > > In scenario testing for syzbot, failure reading from
> > > digitv_ctrl_msg() [1].
> > >
> > > Eg:
> > > [ 91.846657][ T3844] dvb-usb: bulk message failed: -22 (7/0)
> > >
> > > digitv_rc_query() always return 0. But in this case a wrong thing happens.
> > >
> > > Reported-by: [email protected]
> > > Tested-by: [email protected]
> >
> > A fix for this was already merged I'm afraid, see commit eecc70d22ae5
> > ("media: digitv: don't continue if remote control state can't be read").
> >
> > > [1]: https://syzkaller.appspot.com/text?tag=CrashLog&x=16860a63600000
> > > [2]: https://groups.google.com/d/msg/syzkaller-bugs/-TXIJAZ0J9Q/T4PEUQoeAQAJ
> > >
> > > Signed-off-by: Phong Tran <[email protected]>
> > > ---
> > > drivers/media/usb/dvb-usb/digitv.c | 12 ++++++++----
> > > 1 file changed, 8 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/media/usb/dvb-usb/digitv.c b/drivers/media/usb/dvb-usb/digitv.c
> > > index dd5bb230cec1..61bc8945e6b9 100644
> > > --- a/drivers/media/usb/dvb-usb/digitv.c
> > > +++ b/drivers/media/usb/dvb-usb/digitv.c
> > > @@ -231,17 +231,21 @@ static struct rc_map_table rc_map_digitv_table[] = {
> > > static int digitv_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
> > > {
> > > int i;
> > > - u8 key[5];
> > > + u8 key[5] = { 0 };
> >
> > The merged commit does not change this line. Why was this changed?
> >
>
> It would fix the problem that key[0] is never initialized... But the
> correct fix is to make key 4 elements long and delete key[0].
Phong,
Presumably you can fix this? You will have to renumber key[1] to
key[0] and key[2] to key[1] etc... Add a fixes tag.
Fixes: 774c0de4aed4 ("V4L/DVB (4616): [PATCH] Nebula DigiTV USB RC support")
Otherwise if you want I can send the patch.
regards,
dan carpenter