Hello,
syzbot found the following crash on:
HEAD commit: e96407b4 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=15ef3cba600000
kernel config: https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
dashboard link: https://syzkaller.appspot.com/bug?extid=b7f57261c521087d89bb
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16ceae36600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12816f26600000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email protected]
usb 1-1: USB disconnect, device number 2
em28xx 1-1:1.153: Disconnecting em28xx #1
------------[ cut here ]------------
WARNING: CPU: 0 PID: 12 at kernel/workqueue.c:3031
__flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc2+ #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
panic+0x2a3/0x6da kernel/panic.c:219
__warn.cold+0x20/0x4a kernel/panic.c:576
report_bug+0x262/0x2a0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:179 [inline]
fixup_bug arch/x86/kernel/traps.c:174 [inline]
do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026
RIP: 0010:__flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
Code: 9a 22 00 48 c7 c7 20 e4 c5 85 e8 d9 3a 0d 00 0f 0b 45 31 e4 e9 98 86
ff ff e8 51 9a 22 00 48 c7 c7 20 e4 c5 85 e8 be 3a 0d 00 <0f> 0b 45 31 e4
e9 7d 86 ff ff e8 36 9a 22 00 48 c7 c7 20 e4 c5 85
RSP: 0018:ffff8881da20f720 EFLAGS: 00010286
RAX: 0000000000000024 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8128a0fd RDI: ffffed103b441ed6
RBP: ffff8881da20f888 R08: 0000000000000024 R09: fffffbfff11acd9a
R10: fffffbfff11acd99 R11: ffffffff88d66ccf R12: 0000000000000000
R13: 0000000000000001 R14: ffff8881c6685df8 R15: ffff8881d2a85b78
flush_request_modules drivers/media/usb/em28xx/em28xx-cards.c:3325 [inline]
em28xx_usb_disconnect.cold+0x280/0x2a6
drivers/media/usb/em28xx/em28xx-cards.c:4023
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1120 [inline]
device_release_driver_internal+0x404/0x4c0 drivers/base/dd.c:1151
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
device_del+0x420/0xb10 drivers/base/core.c:2288
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at [email protected].
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches
syzbot reports an error on flush_request_modules() for the second device.
This workqueue was never initialised so simply remove the offending line.
usb 1-1: USB disconnect, device number 2
em28xx 1-1:1.153: Disconnecting em28xx #1
------------[ cut here ]------------
WARNING: CPU: 0 PID: 12 at kernel/workqueue.c:3031
__flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc2+ #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
panic+0x2a3/0x6da kernel/panic.c:219
__warn.cold+0x20/0x4a kernel/panic.c:576
report_bug+0x262/0x2a0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:179 [inline]
fixup_bug arch/x86/kernel/traps.c:174 [inline]
do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026
RIP: 0010:__flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
Code: 9a 22 00 48 c7 c7 20 e4 c5 85 e8 d9 3a 0d 00 0f 0b 45 31 e4 e9 98 86
ff ff e8 51 9a 22 00 48 c7 c7 20 e4 c5 85 e8 be 3a 0d 00 <0f> 0b 45 31 e4
e9 7d 86 ff ff e8 36 9a 22 00 48 c7 c7 20 e4 c5 85
RSP: 0018:ffff8881da20f720 EFLAGS: 00010286
RAX: 0000000000000024 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8128a0fd RDI: ffffed103b441ed6
RBP: ffff8881da20f888 R08: 0000000000000024 R09: fffffbfff11acd9a
R10: fffffbfff11acd99 R11: ffffffff88d66ccf R12: 0000000000000000
R13: 0000000000000001 R14: ffff8881c6685df8 R15: ffff8881d2a85b78
flush_request_modules drivers/media/usb/em28xx/em28xx-cards.c:3325 [inline]
em28xx_usb_disconnect.cold+0x280/0x2a6
drivers/media/usb/em28xx/em28xx-cards.c:4023
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1120 [inline]
device_release_driver_internal+0x404/0x4c0 drivers/base/dd.c:1151
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
device_del+0x420/0xb10 drivers/base/core.c:2288
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..
Reported-by: [email protected]
Signed-off-by: Sean Young <[email protected]>
---
drivers/media/usb/em28xx/em28xx-cards.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
index 6e33782c3ca6..5983e72a0622 100644
--- a/drivers/media/usb/em28xx/em28xx-cards.c
+++ b/drivers/media/usb/em28xx/em28xx-cards.c
@@ -4019,7 +4019,6 @@ static void em28xx_usb_disconnect(struct usb_interface *intf)
dev->dev_next->disconnected = 1;
dev_info(&dev->intf->dev, "Disconnecting %s\n",
dev->dev_next->name);
- flush_request_modules(dev->dev_next);
}
dev->disconnected = 1;
--
2.21.0
On Sun, 2019-08-11 at 06:11 +0100, Sean Young wrote:
> syzbot reports an error on flush_request_modules() for the second device.
> This workqueue was never initialised so simply remove the offending line.
>
> usb 1-1: USB disconnect, device number 2
> em28xx 1-1:1.153: Disconnecting em28xx #1
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 12 at kernel/workqueue.c:3031
> __flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
> Kernel panic - not syncing: panic_on_warn set ...
> CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc2+ #25
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Workqueue: usb_hub_wq hub_event
> Call Trace:
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0xca/0x13e lib/dump_stack.c:113
> panic+0x2a3/0x6da kernel/panic.c:219
> __warn.cold+0x20/0x4a kernel/panic.c:576
> report_bug+0x262/0x2a0 lib/bug.c:186
> fixup_bug arch/x86/kernel/traps.c:179 [inline]
> fixup_bug arch/x86/kernel/traps.c:174 [inline]
> do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
> do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
> invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026
> RIP: 0010:__flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
> Code: 9a 22 00 48 c7 c7 20 e4 c5 85 e8 d9 3a 0d 00 0f 0b 45 31 e4 e9 98 86
> ff ff e8 51 9a 22 00 48 c7 c7 20 e4 c5 85 e8 be 3a 0d 00 <0f> 0b 45 31 e4
> e9 7d 86 ff ff e8 36 9a 22 00 48 c7 c7 20 e4 c5 85
> RSP: 0018:ffff8881da20f720 EFLAGS: 00010286
> RAX: 0000000000000024 RBX: dffffc0000000000 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: ffffffff8128a0fd RDI: ffffed103b441ed6
> RBP: ffff8881da20f888 R08: 0000000000000024 R09: fffffbfff11acd9a
> R10: fffffbfff11acd99 R11: ffffffff88d66ccf R12: 0000000000000000
> R13: 0000000000000001 R14: ffff8881c6685df8 R15: ffff8881d2a85b78
> flush_request_modules drivers/media/usb/em28xx/em28xx-cards.c:3325 [inline]
> em28xx_usb_disconnect.cold+0x280/0x2a6
> drivers/media/usb/em28xx/em28xx-cards.c:4023
> usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
> __device_release_driver drivers/base/dd.c:1120 [inline]
> device_release_driver_internal+0x404/0x4c0 drivers/base/dd.c:1151
> bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
> device_del+0x420/0xb10 drivers/base/core.c:2288
> usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
> usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
> hub_port_connect drivers/usb/core/hub.c:4949 [inline]
> hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
> port_event drivers/usb/core/hub.c:5359 [inline]
> hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
> process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
> process_scheduled_works kernel/workqueue.c:2331 [inline]
> worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
> kthread+0x318/0x420 kernel/kthread.c:255
> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
> Kernel Offset: disabled
> Rebooting in 86400 seconds..
>
> Reported-by: [email protected]
> Signed-off-by: Sean Young <[email protected]>
I reviewed the syzbot report, but was left head-scratching and
failing to see how the module-loading worker was supposed to be used :-)
Reviewed-by: Ezequiel Garcia <[email protected]>
Also, this seems a bug, so how about this tag?
Fixes: be7fd3c3a8c5e ("media: em28xx: Hauppauge DualHD second tuner functionality)
> ---
> drivers/media/usb/em28xx/em28xx-cards.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
> index 6e33782c3ca6..5983e72a0622 100644
> --- a/drivers/media/usb/em28xx/em28xx-cards.c
> +++ b/drivers/media/usb/em28xx/em28xx-cards.c
> @@ -4019,7 +4019,6 @@ static void em28xx_usb_disconnect(struct usb_interface *intf)
> dev->dev_next->disconnected = 1;
> dev_info(&dev->intf->dev, "Disconnecting %s\n",
> dev->dev_next->name);
> - flush_request_modules(dev->dev_next);
> }
>
> dev->disconnected = 1;
On Mon, Aug 12, 2019 at 10:21:39AM -0300, Ezequiel Garcia wrote:
> On Sun, 2019-08-11 at 06:11 +0100, Sean Young wrote:
> > syzbot reports an error on flush_request_modules() for the second device.
> > This workqueue was never initialised so simply remove the offending line.
> >
> > usb 1-1: USB disconnect, device number 2
> > em28xx 1-1:1.153: Disconnecting em28xx #1
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 12 at kernel/workqueue.c:3031
> > __flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
> > Kernel panic - not syncing: panic_on_warn set ...
> > CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc2+ #25
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> > Google 01/01/2011
> > Workqueue: usb_hub_wq hub_event
> > Call Trace:
> > __dump_stack lib/dump_stack.c:77 [inline]
> > dump_stack+0xca/0x13e lib/dump_stack.c:113
> > panic+0x2a3/0x6da kernel/panic.c:219
> > __warn.cold+0x20/0x4a kernel/panic.c:576
> > report_bug+0x262/0x2a0 lib/bug.c:186
> > fixup_bug arch/x86/kernel/traps.c:179 [inline]
> > fixup_bug arch/x86/kernel/traps.c:174 [inline]
> > do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
> > do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
> > invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026
> > RIP: 0010:__flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
> > Code: 9a 22 00 48 c7 c7 20 e4 c5 85 e8 d9 3a 0d 00 0f 0b 45 31 e4 e9 98 86
> > ff ff e8 51 9a 22 00 48 c7 c7 20 e4 c5 85 e8 be 3a 0d 00 <0f> 0b 45 31 e4
> > e9 7d 86 ff ff e8 36 9a 22 00 48 c7 c7 20 e4 c5 85
> > RSP: 0018:ffff8881da20f720 EFLAGS: 00010286
> > RAX: 0000000000000024 RBX: dffffc0000000000 RCX: 0000000000000000
> > RDX: 0000000000000000 RSI: ffffffff8128a0fd RDI: ffffed103b441ed6
> > RBP: ffff8881da20f888 R08: 0000000000000024 R09: fffffbfff11acd9a
> > R10: fffffbfff11acd99 R11: ffffffff88d66ccf R12: 0000000000000000
> > R13: 0000000000000001 R14: ffff8881c6685df8 R15: ffff8881d2a85b78
> > flush_request_modules drivers/media/usb/em28xx/em28xx-cards.c:3325 [inline]
> > em28xx_usb_disconnect.cold+0x280/0x2a6
> > drivers/media/usb/em28xx/em28xx-cards.c:4023
> > usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
> > __device_release_driver drivers/base/dd.c:1120 [inline]
> > device_release_driver_internal+0x404/0x4c0 drivers/base/dd.c:1151
> > bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
> > device_del+0x420/0xb10 drivers/base/core.c:2288
> > usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
> > usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
> > hub_port_connect drivers/usb/core/hub.c:4949 [inline]
> > hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
> > port_event drivers/usb/core/hub.c:5359 [inline]
> > hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
> > process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
> > process_scheduled_works kernel/workqueue.c:2331 [inline]
> > worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
> > kthread+0x318/0x420 kernel/kthread.c:255
> > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
> > Kernel Offset: disabled
> > Rebooting in 86400 seconds..
> >
> > Reported-by: [email protected]
> > Signed-off-by: Sean Young <[email protected]>
>
> I reviewed the syzbot report, but was left head-scratching and
> failing to see how the module-loading worker was supposed to be used :-)
>
> Reviewed-by: Ezequiel Garcia <[email protected]>
>
> Also, this seems a bug, so how about this tag?
>
> Fixes: be7fd3c3a8c5e ("media: em28xx: Hauppauge DualHD second tuner functionality)
Thank you for the review and yes it does need that tag.
Thanks
sean
>
> > ---
> > drivers/media/usb/em28xx/em28xx-cards.c | 1 -
> > 1 file changed, 1 deletion(-)
> >
> > diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
> > index 6e33782c3ca6..5983e72a0622 100644
> > --- a/drivers/media/usb/em28xx/em28xx-cards.c
> > +++ b/drivers/media/usb/em28xx/em28xx-cards.c
> > @@ -4019,7 +4019,6 @@ static void em28xx_usb_disconnect(struct usb_interface *intf)
> > dev->dev_next->disconnected = 1;
> > dev_info(&dev->intf->dev, "Disconnecting %s\n",
> > dev->dev_next->name);
> > - flush_request_modules(dev->dev_next);
> > }
> >
> > dev->disconnected = 1;
>
Hi Brad,
On Mon, Aug 12, 2019 at 10:21:39AM -0300, Ezequiel Garcia wrote:
> On Sun, 2019-08-11 at 06:11 +0100, Sean Young wrote:
> > syzbot reports an error on flush_request_modules() for the second device.
> > This workqueue was never initialised so simply remove the offending line.
> >
> > usb 1-1: USB disconnect, device number 2
> > em28xx 1-1:1.153: Disconnecting em28xx #1
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 12 at kernel/workqueue.c:3031
> > __flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
> > Kernel panic - not syncing: panic_on_warn set ...
> > CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc2+ #25
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> > Google 01/01/2011
> > Workqueue: usb_hub_wq hub_event
> > Call Trace:
> > __dump_stack lib/dump_stack.c:77 [inline]
> > dump_stack+0xca/0x13e lib/dump_stack.c:113
> > panic+0x2a3/0x6da kernel/panic.c:219
> > __warn.cold+0x20/0x4a kernel/panic.c:576
> > report_bug+0x262/0x2a0 lib/bug.c:186
> > fixup_bug arch/x86/kernel/traps.c:179 [inline]
> > fixup_bug arch/x86/kernel/traps.c:174 [inline]
> > do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
> > do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
> > invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026
> > RIP: 0010:__flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
> > Code: 9a 22 00 48 c7 c7 20 e4 c5 85 e8 d9 3a 0d 00 0f 0b 45 31 e4 e9 98 86
> > ff ff e8 51 9a 22 00 48 c7 c7 20 e4 c5 85 e8 be 3a 0d 00 <0f> 0b 45 31 e4
> > e9 7d 86 ff ff e8 36 9a 22 00 48 c7 c7 20 e4 c5 85
> > RSP: 0018:ffff8881da20f720 EFLAGS: 00010286
> > RAX: 0000000000000024 RBX: dffffc0000000000 RCX: 0000000000000000
> > RDX: 0000000000000000 RSI: ffffffff8128a0fd RDI: ffffed103b441ed6
> > RBP: ffff8881da20f888 R08: 0000000000000024 R09: fffffbfff11acd9a
> > R10: fffffbfff11acd99 R11: ffffffff88d66ccf R12: 0000000000000000
> > R13: 0000000000000001 R14: ffff8881c6685df8 R15: ffff8881d2a85b78
> > flush_request_modules drivers/media/usb/em28xx/em28xx-cards.c:3325 [inline]
> > em28xx_usb_disconnect.cold+0x280/0x2a6
> > drivers/media/usb/em28xx/em28xx-cards.c:4023
> > usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
> > __device_release_driver drivers/base/dd.c:1120 [inline]
> > device_release_driver_internal+0x404/0x4c0 drivers/base/dd.c:1151
> > bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
> > device_del+0x420/0xb10 drivers/base/core.c:2288
> > usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
> > usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
> > hub_port_connect drivers/usb/core/hub.c:4949 [inline]
> > hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
> > port_event drivers/usb/core/hub.c:5359 [inline]
> > hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
> > process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
> > process_scheduled_works kernel/workqueue.c:2331 [inline]
> > worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
> > kthread+0x318/0x420 kernel/kthread.c:255
> > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
> > Kernel Offset: disabled
> > Rebooting in 86400 seconds..
> >
> > Reported-by: [email protected]
> > Signed-off-by: Sean Young <[email protected]>
>
> I reviewed the syzbot report, but was left head-scratching and
> failing to see how the module-loading worker was supposed to be used :-)
>
> Reviewed-by: Ezequiel Garcia <[email protected]>
>
> Also, this seems a bug, so how about this tag?
>
> Fixes: be7fd3c3a8c5e ("media: em28xx: Hauppauge DualHD second tuner functionality)
Would you mind reviewing this change please Brad? You added the dual_ts
feature to the driver so it would be good to have your view on this.
Thanks
Sean
>
> > ---
> > drivers/media/usb/em28xx/em28xx-cards.c | 1 -
> > 1 file changed, 1 deletion(-)
> >
> > diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
> > index 6e33782c3ca6..5983e72a0622 100644
> > --- a/drivers/media/usb/em28xx/em28xx-cards.c
> > +++ b/drivers/media/usb/em28xx/em28xx-cards.c
> > @@ -4019,7 +4019,6 @@ static void em28xx_usb_disconnect(struct usb_interface *intf)
> > dev->dev_next->disconnected = 1;
> > dev_info(&dev->intf->dev, "Disconnecting %s\n",
> > dev->dev_next->name);
> > - flush_request_modules(dev->dev_next);
> > }
> >
> > dev->disconnected = 1;
>
Hey Sean,
On 13/08/2019 04.10, Sean Young wrote:
> Hi Brad,
>
> On Mon, Aug 12, 2019 at 10:21:39AM -0300, Ezequiel Garcia wrote:
>> On Sun, 2019-08-11 at 06:11 +0100, Sean Young wrote:
>>> syzbot reports an error on flush_request_modules() for the second device.
>>> This workqueue was never initialised so simply remove the offending line.
>>>
>>> usb 1-1: USB disconnect, device number 2
>>> em28xx 1-1:1.153: Disconnecting em28xx #1
>>> ------------[ cut here ]------------
>>> WARNING: CPU: 0 PID: 12 at kernel/workqueue.c:3031
>>> __flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
>>> Kernel panic - not syncing: panic_on_warn set ...
>>> CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc2+ #25
>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>>> Google 01/01/2011
>>> Workqueue: usb_hub_wq hub_event
>>> Call Trace:
>>> __dump_stack lib/dump_stack.c:77 [inline]
>>> dump_stack+0xca/0x13e lib/dump_stack.c:113
>>> panic+0x2a3/0x6da kernel/panic.c:219
>>> __warn.cold+0x20/0x4a kernel/panic.c:576
>>> report_bug+0x262/0x2a0 lib/bug.c:186
>>> fixup_bug arch/x86/kernel/traps.c:179 [inline]
>>> fixup_bug arch/x86/kernel/traps.c:174 [inline]
>>> do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
>>> do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
>>> invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026
>>> RIP: 0010:__flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
>>> Code: 9a 22 00 48 c7 c7 20 e4 c5 85 e8 d9 3a 0d 00 0f 0b 45 31 e4 e9 98 86
>>> ff ff e8 51 9a 22 00 48 c7 c7 20 e4 c5 85 e8 be 3a 0d 00 <0f> 0b 45 31 e4
>>> e9 7d 86 ff ff e8 36 9a 22 00 48 c7 c7 20 e4 c5 85
>>> RSP: 0018:ffff8881da20f720 EFLAGS: 00010286
>>> RAX: 0000000000000024 RBX: dffffc0000000000 RCX: 0000000000000000
>>> RDX: 0000000000000000 RSI: ffffffff8128a0fd RDI: ffffed103b441ed6
>>> RBP: ffff8881da20f888 R08: 0000000000000024 R09: fffffbfff11acd9a
>>> R10: fffffbfff11acd99 R11: ffffffff88d66ccf R12: 0000000000000000
>>> R13: 0000000000000001 R14: ffff8881c6685df8 R15: ffff8881d2a85b78
>>> flush_request_modules drivers/media/usb/em28xx/em28xx-cards.c:3325 [inline]
>>> em28xx_usb_disconnect.cold+0x280/0x2a6
>>> drivers/media/usb/em28xx/em28xx-cards.c:4023
>>> usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
>>> __device_release_driver drivers/base/dd.c:1120 [inline]
>>> device_release_driver_internal+0x404/0x4c0 drivers/base/dd.c:1151
>>> bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
>>> device_del+0x420/0xb10 drivers/base/core.c:2288
>>> usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
>>> usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
>>> hub_port_connect drivers/usb/core/hub.c:4949 [inline]
>>> hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
>>> port_event drivers/usb/core/hub.c:5359 [inline]
>>> hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
>>> process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
>>> process_scheduled_works kernel/workqueue.c:2331 [inline]
>>> worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
>>> kthread+0x318/0x420 kernel/kthread.c:255
>>> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
>>> Kernel Offset: disabled
>>> Rebooting in 86400 seconds..
>>>
>>> Reported-by: [email protected]
>>> Signed-off-by: Sean Young <[email protected]>
>> I reviewed the syzbot report, but was left head-scratching and
>> failing to see how the module-loading worker was supposed to be used :-)
>>
>> Reviewed-by: Ezequiel Garcia <[email protected]>
>>
>> Also, this seems a bug, so how about this tag?
>>
>> Fixes: be7fd3c3a8c5e ("media: em28xx: Hauppauge DualHD second tuner functionality)
> Would you mind reviewing this change please Brad? You added the dual_ts
> feature to the driver so it would be good to have your view on this.
>
> Thanks
> Sean
Hmmm. I've never encountered this oops, nor had it reported to me. Looks
like the second device indeed never calls request_modules, and when I
did the cleanup I just duplicated all the teardown. Since everything
works without the second workqueue already, I don't think the second
device needs to initialize it's own. So, I think your solution is proper.
Reviewed-by: Brad Love <[email protected]>
>>> ---
>>> drivers/media/usb/em28xx/em28xx-cards.c | 1 -
>>> 1 file changed, 1 deletion(-)
>>>
>>> diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
>>> index 6e33782c3ca6..5983e72a0622 100644
>>> --- a/drivers/media/usb/em28xx/em28xx-cards.c
>>> +++ b/drivers/media/usb/em28xx/em28xx-cards.c
>>> @@ -4019,7 +4019,6 @@ static void em28xx_usb_disconnect(struct usb_interface *intf)
>>> dev->dev_next->disconnected = 1;
>>> dev_info(&dev->intf->dev, "Disconnecting %s\n",
>>> dev->dev_next->name);
>>> - flush_request_modules(dev->dev_next);
>>> }
>>>
>>> dev->disconnected = 1;
Hi Brad,
On Tue, Aug 13, 2019 at 01:48:34PM -0500, Brad Love wrote:
> > On Mon, Aug 12, 2019 at 10:21:39AM -0300, Ezequiel Garcia wrote:
> >> On Sun, 2019-08-11 at 06:11 +0100, Sean Young wrote:
> >>> syzbot reports an error on flush_request_modules() for the second device.
> >>> This workqueue was never initialised so simply remove the offending line.
> >>>
> >>> usb 1-1: USB disconnect, device number 2
> >>> em28xx 1-1:1.153: Disconnecting em28xx #1
> >>> ------------[ cut here ]------------
> >>> WARNING: CPU: 0 PID: 12 at kernel/workqueue.c:3031
> >>> __flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
> >>> Kernel panic - not syncing: panic_on_warn set ...
> >>> CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc2+ #25
> >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> >>> Google 01/01/2011
> >>> Workqueue: usb_hub_wq hub_event
> >>> Call Trace:
> >>> __dump_stack lib/dump_stack.c:77 [inline]
> >>> dump_stack+0xca/0x13e lib/dump_stack.c:113
> >>> panic+0x2a3/0x6da kernel/panic.c:219
> >>> __warn.cold+0x20/0x4a kernel/panic.c:576
> >>> report_bug+0x262/0x2a0 lib/bug.c:186
> >>> fixup_bug arch/x86/kernel/traps.c:179 [inline]
> >>> fixup_bug arch/x86/kernel/traps.c:174 [inline]
> >>> do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
> >>> do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
> >>> invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026
> >>> RIP: 0010:__flush_work.cold+0x2c/0x36 kernel/workqueue.c:3031
> >>> Code: 9a 22 00 48 c7 c7 20 e4 c5 85 e8 d9 3a 0d 00 0f 0b 45 31 e4 e9 98 86
> >>> ff ff e8 51 9a 22 00 48 c7 c7 20 e4 c5 85 e8 be 3a 0d 00 <0f> 0b 45 31 e4
> >>> e9 7d 86 ff ff e8 36 9a 22 00 48 c7 c7 20 e4 c5 85
> >>> RSP: 0018:ffff8881da20f720 EFLAGS: 00010286
> >>> RAX: 0000000000000024 RBX: dffffc0000000000 RCX: 0000000000000000
> >>> RDX: 0000000000000000 RSI: ffffffff8128a0fd RDI: ffffed103b441ed6
> >>> RBP: ffff8881da20f888 R08: 0000000000000024 R09: fffffbfff11acd9a
> >>> R10: fffffbfff11acd99 R11: ffffffff88d66ccf R12: 0000000000000000
> >>> R13: 0000000000000001 R14: ffff8881c6685df8 R15: ffff8881d2a85b78
> >>> flush_request_modules drivers/media/usb/em28xx/em28xx-cards.c:3325 [inline]
> >>> em28xx_usb_disconnect.cold+0x280/0x2a6
> >>> drivers/media/usb/em28xx/em28xx-cards.c:4023
> >>> usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
> >>> __device_release_driver drivers/base/dd.c:1120 [inline]
> >>> device_release_driver_internal+0x404/0x4c0 drivers/base/dd.c:1151
> >>> bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
> >>> device_del+0x420/0xb10 drivers/base/core.c:2288
> >>> usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
> >>> usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
> >>> hub_port_connect drivers/usb/core/hub.c:4949 [inline]
> >>> hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
> >>> port_event drivers/usb/core/hub.c:5359 [inline]
> >>> hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
> >>> process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
> >>> process_scheduled_works kernel/workqueue.c:2331 [inline]
> >>> worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
> >>> kthread+0x318/0x420 kernel/kthread.c:255
> >>> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
> >>> Kernel Offset: disabled
> >>> Rebooting in 86400 seconds..
> >>>
> >>> Reported-by: [email protected]
> >>> Signed-off-by: Sean Young <[email protected]>
> >> I reviewed the syzbot report, but was left head-scratching and
> >> failing to see how the module-loading worker was supposed to be used :-)
> >>
> >> Reviewed-by: Ezequiel Garcia <[email protected]>
> >>
> >> Also, this seems a bug, so how about this tag?
> >>
> >> Fixes: be7fd3c3a8c5e ("media: em28xx: Hauppauge DualHD second tuner functionality)
> > Would you mind reviewing this change please Brad? You added the dual_ts
> > feature to the driver so it would be good to have your view on this.
> >
> > Thanks
> > Sean
>
>
> Hmmm. I've never encountered this oops, nor had it reported to me. Looks
> like the second device indeed never calls request_modules, and when I
> did the cleanup I just duplicated all the teardown. Since everything
> works without the second workqueue already, I don't think the second
> device needs to initialize it's own. So, I think your solution is proper.
>
>
> Reviewed-by: Brad Love <[email protected]>
Great, thank you!
If I understand this correctly, then if you build your kernel with KASAN
and UBSAN then I _think_ this is caught.
Thanks
Sean