| Message ID | 20190811051110.hsdwmjrbvqgrmssc@gofer.mess.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | media: em28xx: modules workqueue not inited for 2nd device | expand |
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: syzbot+b7f57261c521087d89bb@syzkaller.appspotmail.com > Signed-off-by: Sean Young <sean@mess.org> 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 <ezequiel@collabora.com> 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: syzbot+b7f57261c521087d89bb@syzkaller.appspotmail.com > > Signed-off-by: Sean Young <sean@mess.org> > > 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 <ezequiel@collabora.com> > > 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: syzbot+b7f57261c521087d89bb@syzkaller.appspotmail.com > > Signed-off-by: Sean Young <sean@mess.org> > > 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 <ezequiel@collabora.com> > > 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: syzbot+b7f57261c521087d89bb@syzkaller.appspotmail.com >>> Signed-off-by: Sean Young <sean@mess.org> >> 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 <ezequiel@collabora.com> >> >> 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 <brad@nextdimension.cc> >>> --- >>> 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: syzbot+b7f57261c521087d89bb@syzkaller.appspotmail.com > >>> Signed-off-by: Sean Young <sean@mess.org> > >> 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 <ezequiel@collabora.com> > >> > >> 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 <brad@nextdimension.cc> 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
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;
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: syzbot+b7f57261c521087d89bb@syzkaller.appspotmail.com Signed-off-by: Sean Young <sean@mess.org> --- drivers/media/usb/em28xx/em28xx-cards.c | 1 - 1 file changed, 1 deletion(-)