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(envelope-from ); Sun, 26 Jul 2026 07:48:51 +0000 Date: Sun, 26 Jul 2026 09:48:50 +0200 Message-ID: <875x22b38d.wl-tiwai@suse.de> From: Takashi Iwai To: Shuangpeng Cc: Takashi Iwai , Jaroslav Kysela , Takashi Iwai , Kees Cook , linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [BUG] ALSA: usb: 6fire: KASAN slab-use-after-free in dummy_timer In-Reply-To: References: <20260724030900.1984491-1-shuangpeng.kernel@gmail.com> <87bjbwesqq.wl-tiwai@suse.de> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/30.2 Mule/6.0 Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-Spam-Score: -1.80 X-Spam-Level: X-Spam-Flag: NO X-Spamd-Result: default: False [-1.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; TAGGED_RCPT(0.00)[]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; FUZZY_RATELIMITED(0.00)[rspamd.com]; FREEMAIL_TO(0.00)[gmail.com]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_SEVEN(0.00)[7]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:email,suse.de:mid] On Fri, 24 Jul 2026 16:49:27 +0200, Shuangpeng wrote: > > > > > On Jul 24, 2026, at 03:45, Takashi Iwai wrote: > > > > On Fri, 24 Jul 2026 05:07:50 +0200, > > Shuangpeng Bai wrote: > >> > >> Hi Kernel Maintainers, > >> > >> I hit the following report while testing current upstream kernel: > >> > >> KASAN: slab-use-after-free in dummy_timer > >> > >> on commit: fce2dfa773ced15f27dd27cd0b482a7473cdcf2a (2026-07-16) > >> > >> The reproducer and .config files are here. > >> https://gist.github.com/shuangpengbai/a410bc05b4f22d1ba4ce7ef059043fea > >> > >> I'm happy to test debug patches or provide additional information. > >> > >> Reported-by: Shuangpeng Bai > >> > >> [ 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) > > > > Through a quick glance, this looks like a stale URB firing after the > > release. Does the patch below work? > > > > I tested the patch. The reproducer does not trigger the bug on my side. > Thanks for your patch. Thanks for quick testing. I submitted a proper fix patch for merging to the upstream now. Takashi