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linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <20260724030900.1984491-1-shuangpeng.kernel@gmail.com> <87bjbwesqq.wl-tiwai@suse.de> To: Takashi Iwai X-Mailer: Apple Mail (2.3864.600.51.1.1) > On Jul 24, 2026, at 03:45, Takashi Iwai wrote: >=20 > On Fri, 24 Jul 2026 05:07:50 +0200, > Shuangpeng Bai wrote: >>=20 >> Hi Kernel Maintainers, >>=20 >> I hit the following report while testing current upstream kernel: >>=20 >> KASAN: slab-use-after-free in dummy_timer >>=20 >> on commit: fce2dfa773ced15f27dd27cd0b482a7473cdcf2a (2026-07-16) >>=20 >> The reproducer and .config files are here. >> = https://gist.github.com/shuangpengbai/a410bc05b4f22d1ba4ce7ef059043fea >>=20 >> I'm happy to test debug patches or provide additional information. >>=20 >> Reported-by: Shuangpeng Bai >>=20 >> [ 400.891255][ C0] BUG: KASAN: slab-use-after-free in dummy_timer = (drivers/usb/common/usb-otg-fsm.c:393) >> [ 400.891273][ C0] Read of size 4 at addr ffff8881789bc20c by = task kworker/0:2/773 >> [ 400.891276][ C0] >> [ 400.891291][ C0] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX = + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 >> [ 400.891294][ C0] Workqueue: usb_hub_wq hub_event >> [ 400.891299][ C0] Call Trace: >> [ 400.891301][ C0] >> [ 400.891302][ C0] dump_stack_lvl (lib/dump_stack.c:94 = lib/dump_stack.c:120) >> [ 400.891306][ C0] print_report (mm/kasan/report.c:378 = mm/kasan/report.c:482) >> [ 400.891322][ C0] kasan_report (mm/kasan/report.c:595) >> [ 400.891330][ C0] dummy_timer = (drivers/usb/common/usb-otg-fsm.c:393) >> [ 400.891397][ C0] __hrtimer_run_queues = (kernel/time/hrtimer.c:2032 kernel/time/hrtimer.c:2096) >> [ 400.891403][ C0] hrtimer_run_softirq = (kernel/time/hrtimer.c:2113) >> [ 400.891414][ C0] handle_softirqs (kernel/softirq.c:622) >> [ 400.891420][ C0] __irq_exit_rcu (kernel/softirq.c:656 = kernel/softirq.c:496 kernel/softirq.c:735) >> [ 400.891423][ C0] sysvec_apic_timer_interrupt = (arch/x86/kernel/apic/apic.c:1062 arch/x86/kernel/apic/apic.c:1062) >> [ 400.891427][ C0] >> [ 400.891428][ C0] >> [ 400.891579][ C0] really_probe (drivers/base/dd.c:644 = drivers/base/dd.c:706) >> [ 400.891582][ C0] __driver_probe_device (drivers/base/dd.c:868) >> [ 400.891585][ C0] driver_probe_device (drivers/base/dd.c:898) >> [ 400.891588][ C0] __device_attach_driver = (drivers/base/dd.c:1026) >> [ 400.891593][ C0] bus_for_each_drv (drivers/base/bus.c:500) >> [ 400.891615][ C0] __device_attach (drivers/base/dd.c:1098) >> [ 400.891631][ C0] device_initial_probe (drivers/base/dd.c:1153) >> [ 400.891634][ C0] bus_probe_device (drivers/base/bus.c:620) >> [ 400.891637][ C0] device_add (drivers/base/core.c:3772) >> [ 400.891641][ C0] usb_set_configuration = (drivers/usb/core/message.c:2268) >> [ 400.891647][ C0] usb_generic_driver_probe = (drivers/usb/core/generic.c:250) >> [ 400.891651][ C0] usb_probe_device = (drivers/usb/core/driver.c:291) >> [ 400.891653][ C0] really_probe (drivers/base/dd.c:? = drivers/base/dd.c:706) >> [ 400.891656][ C0] __driver_probe_device (drivers/base/dd.c:868) >> [ 400.891663][ C0] driver_probe_device (drivers/base/dd.c:898) >> [ 400.891665][ C0] __device_attach_driver = (drivers/base/dd.c:1026) >> [ 400.891671][ C0] bus_for_each_drv (drivers/base/bus.c:500) >> [ 400.891685][ C0] __device_attach (drivers/base/dd.c:1098) >> [ 400.891704][ C0] device_initial_probe (drivers/base/dd.c:1153) >> [ 400.891707][ C0] bus_probe_device (drivers/base/bus.c:620) >> [ 400.891710][ C0] device_add (drivers/base/core.c:3772) >> [ 400.891714][ C0] usb_new_device (drivers/usb/core/hub.c:2695) >> [ 400.891726][ C0] hub_event (drivers/usb/core/hub.c:5567 = drivers/usb/core/hub.c:5707 drivers/usb/core/hub.c:5871 = drivers/usb/core/hub.c:5953) >> [ 400.891743][ C0] process_scheduled_works = (kernel/workqueue.c:3322 kernel/workqueue.c:3405) >> [ 400.891748][ C0] worker_thread (kernel/workqueue.c:3486) >> [ 400.891756][ C0] kthread (kernel/kthread.c:436) >> [ 400.891764][ C0] ret_from_fork (arch/x86/kernel/process.c:158) >> [ 400.891790][ C0] ret_from_fork_asm = (arch/x86/entry/entry_64.S:245) >> [ 400.891795][ C0] >> [ 400.891797][ C0] Freed by task 773 on cpu 0 at 400.890164s: >> [ 400.891805][ C0] kasan_save_track (mm/kasan/common.c:57 = mm/kasan/common.c:78) >> [ 400.891813][ C0] kasan_save_free_info (mm/kasan/generic.c:584) >> [ 400.891821][ C0] __kasan_slab_free (mm/kasan/common.c:253 = mm/kasan/common.c:285) >> [ 400.891824][ C0] kfree (./include/linux/kasan.h:235 = mm/slub.c:2705 mm/slub.c:6405 mm/slub.c:6720) >> [ 400.891827][ C0] usb6fire_comm_destroy = (sound/usb/6fire/comm.c:197) >> [ 400.891830][ C0] usb6fire_card_free = (sound/usb/6fire/chip.c:65) >> [ 400.891832][ C0] release_card_device (sound/core/init.c:594 = sound/core/init.c:153) >> [ 400.891852][ C0] kobject_put (lib/kobject.c:689 = lib/kobject.c:720 ./include/linux/kref.h:65 lib/kobject.c:737) >> [ 400.891855][ C0] snd_card_free (sound/core/init.c:626 = sound/core/init.c:658) >> [ 400.891858][ C0] usb6fire_chip_probe = (sound/usb/6fire/chip.c:153) >> [ 400.891860][ C0] usb_probe_interface = (drivers/usb/core/driver.c:396) >=20 > Through a quick glance, this looks like a stale URB firing after the > release. Does the patch below work? >=20 I tested the patch. The reproducer does not trigger the bug on my side. Thanks for your patch. > thanks, >=20 > Takashi >=20 > -- 8< -- > --- a/sound/usb/6fire/chip.c > +++ b/sound/usb/6fire/chip.c > @@ -150,6 +150,10 @@ static int usb6fire_chip_probe(struct = usb_interface *intf, > return 0; >=20 > destroy_chip: > + chip->shutdown =3D true; > + if (card) > + snd_card_disconnect(card); > + usb6fire_chip_abort(chip); > snd_card_free(card); > return ret; > }