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From: syzbot <syzbot+919c31c248e8a37b89d1@syzkaller.appspotmail.com>
To: anna-maria@linutronix.de, frederic@kernel.org,
	 linux-kernel@vger.kernel.org, linux-sound@vger.kernel.org,
	 syzkaller-bugs@googlegroups.com, tglx@kernel.org
Subject: Re: [syzbot] [sound?] BUG: scheduling while atomic in drain_urb_queue
Date: Fri, 28 Aug 2026 09:17:32 -0700	[thread overview]
Message-ID: <6a91b49c.1d9ded08.62e62.00f1.GAE@google.com> (raw)
In-Reply-To: <6a8a5f45.ae6ddae5.3da009.005f.GAE@google.com>

syzbot has found a reproducer for the following issue on:

HEAD commit:    1b78070aaef6 Merge tag 'net-7.3-rc1' of git://git.kernel.o..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=13016d79580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=19560cab9a915237
dashboard link: https://syzkaller.appspot.com/bug?extid=919c31c248e8a37b89d1
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=162add79580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+919c31c248e8a37b89d1@syzkaller.appspotmail.com

usb 33-1: config 1 interface 0 altsetting 1 bulk endpoint 0x1 has invalid maxpacket 64
usb 33-1: config 1 interface 0 altsetting 1 bulk endpoint 0x82 has invalid maxpacket 64
usb 33-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
BUG: scheduling while atomic: kworker/0:0/9/0x00010001
locks held by kworker/0:0/9: 7, on CPU#0:
 #0: ffff888023287940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1466/0x1b10 kernel/workqueue.c:3362
 #1: ffffc900000e7d08 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3363
 #2: ffff88802c0c21d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #2: ffff88802c0c21d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bb/0x4420 drivers/usb/core/hub.c:5912
 #3: ffff888023ae91d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #3: ffff888023ae91d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
 #4: ffff8880348291a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #4: ffff8880348291a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1073
 #5: ffffffff90bc96c0 (register_mutex#6){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
 #5: ffffffff90bc96c0 (register_mutex#6){+.+.}-{4:4}, at: usb_audio_probe+0x385/0x3b10 sound/usb/card.c:985
 #6: ffff8880268bc160 (&rmidi->open_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
 #6: ffff8880268bc160 (&rmidi->open_mutex){+.+.}-{4:4}, at: rawmidi_release_priv+0x45/0x280 sound/core/rawmidi.c:574
Modules linked in:
Preemption disabled at:
[<ffffffff8bcf4ceb>] __mutex_lock_common kernel/locking/mutex.c:645 [inline]
[<ffffffff8bcf4ceb>] __mutex_lock+0x17b/0x1bc0 kernel/locking/mutex.c:821
Kernel panic - not syncing: scheduling while atomic: panic_on_warn set ...
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 vpanic+0x553/0x970 kernel/panic.c:651
 panic+0xd1/0xe0 kernel/panic.c:788
 check_panic_on_warn kernel/panic.c:525 [inline]
 check_panic_on_warn.cold+0x19/0x34 kernel/panic.c:520
 __schedule_bug.cold+0xc4/0xf4 kernel/sched/core.c:6076
 schedule_debug kernel/sched/core.c:6105 [inline]
 __schedule+0x4066/0x6920 kernel/sched/core.c:7119
 __schedule_loop kernel/sched/core.c:7347 [inline]
 schedule+0xdd/0x2c0 kernel/sched/core.c:7362
 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
 drain_urb_queue.part.0+0x303/0x470 sound/usb/midi2.c:246
 drain_urb_queue sound/usb/midi2.c:242 [inline]
 snd_usb_midi_v2_drain+0x79/0xb0 sound/usb/midi2.c:383
 snd_ump_rawmidi_drain+0x85/0xb0 sound/core/ump.c:294
 snd_rawmidi_drain_output+0x3b3/0x880 sound/core/rawmidi.c:282
 close_substream.part.0+0x3eb/0x860 sound/core/rawmidi.c:551
 close_substream include/linux/mutex.h:253 [inline]
 rawmidi_release_priv+0x210/0x280 sound/core/rawmidi.c:580
 snd_rawmidi_kernel_release+0x3a/0xd0 sound/core/rawmidi.c:596
 ump_request_close sound/core/ump.c:623 [inline]
 snd_ump_parse_endpoint+0x15f/0xb00 sound/core/ump.c:1135
 parse_ump_endpoints sound/usb/midi2.c:810 [inline]
 snd_usb_midi_v2_create+0x1b97/0x4070 sound/usb/midi2.c:1158
 snd_usb_create_quirk+0xad/0xf0 sound/usb/quirks.c:544
 usb_audio_probe+0x96e/0x3b10 sound/usb/card.c:1058
 usb_probe_interface+0x386/0x9b0 drivers/usb/core/driver.c:399
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x210/0x460 drivers/base/dd.c:868
 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
 __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x64/0x160 drivers/base/bus.c:620
 device_add+0x121d/0x1970 drivers/base/core.c:3776
 usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268
 usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
 usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x210/0x460 drivers/base/dd.c:868
 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
 __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x64/0x160 drivers/base/bus.c:620
 device_add+0x121d/0x1970 drivers/base/core.c:3776
 usb_new_device.part.0+0xcc2/0x1686 drivers/usb/core/hub.c:2708
 usb_new_device include/linux/workqueue.h:715 [inline]
 hub_port_connect drivers/usb/core/hub.c:5580 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
 port_event drivers/usb/core/hub.c:5884 [inline]
 hub_event.cold+0x1e3/0xe90 drivers/usb/core/hub.c:5966
 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3387
 process_scheduled_works kernel/workqueue.c:3470 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3551
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

      reply	other threads:[~2026-08-28 16:17 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-23  2:47 [syzbot] [kernel?] " syzbot
2026-08-28 16:17 ` syzbot [this message]

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