From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.167.200 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792680793; b=bVXLzJCNzIluyaB0TvC0W89mNVfvEiSdxGg8oEwSor8rEGVUgvKwUDsuoWc+TCauXffJ 4q2bdsM1MO0soP0kdEOVH9C/MT7ltPXnO+l5EBkIC7pu0V64uDebJPv5hWm7vxRYJlrYI zEWZeq6fFQwt6YKWSw1xV0JM7KchaxHt9k6RM4kSBczc5KiPrsv9yrQrr96tuV+U32tRB uTjnpiZ1k5ximiNXUTZ3tL5EdUDOZn5SPxEo2+bq7FmtE503LYlVpeRBQHByYxNvwDpEs PLiVT7klChLcasSMSDYqKj6LFkEzr87B5A0fTX8MZfKkEP+aUUbx/qbswGURJGtBPmQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792680793; h=DMARC-Filter:Received:X-Google-DKIM-Signature:X-Gm-Message-State: MIME-Version:X-Received:Date:In-Reply-To:X-Google-Appengine-App-Id: X-Google-Appengine-App-Id-Alias:Message-ID:Subject:From:To: Content-Type:Content-Transfer-Encoding; bh=+9yXn1W9xrKqYjqwzCBrzZnC8Ug2E7ECksvMXjcNhhU=; b=BtisuiVhhn7is2eji2N2gtXoJb0CCa0qmHe1FSQQsam5NQOlUJf+FP6YRAdOrmMe+ot1 rV6mcgINjvOtL5Fy21zhtgc4djA4h2QJY43/WwU2j/870GbjocqfUfrQ3N19pN5IcGTJE xERHOWOhdvpGzmHNm9Ma5R08bsUl5nf6YecMIA74v3aaXBKb3o/bzBIkWj7hn9sgJ8PQt Q2xJehTfJbhEleQp3JVPNpIEmXmEzke14YG6JdKQSryU++51c++bkXWw21e7wNutZm5J+ +SkGQqAhYV+5PfywWWalhWOSBzsonbS8BQ6nHpDmDILW4GwIusu60AW4wZRVEjgecCA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.remote-ip=209.85.167.200 Received: from mail-oi1-f200.google.com (mail-oi1-f200.google.com [209.85.167.200]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C12DC606A319 for ; Thu, 22 Oct 2026 14:53:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org C12DC606A319 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oi1-f200.google.com with SMTP id 5614622812f47-4c55ba309c2so2608664b6e.1 for ; Thu, 22 Oct 2026 07:53:12 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1792680791; x=1793285591; h=content-transfer-encoding:content-type:to:from:subject:message-id :in-reply-to:date:mime-version:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to:content-type; bh=+9yXn1W9xrKqYjqwzCBrzZnC8Ug2E7ECksvMXjcNhhU=; b=HlCrTYb+FFVyBaTX6aTHg+PEFkYAwXsJYyt0B73gJIQ57X+a6Z/jITDo+xiVxefwsy 61E855niTLn7oYri1IQKWoTB6gbSWH998k3//wmwW7aSRbVh4VuHUz/nRqRLw86Xd6qw mr3kBxCMLpqk5AtppKS0489rPyzyTpZ5TrBJwR5M9baToZQoDCU8U6H1jEnappDqffBZ vcLNZq+cQ1mz4KsxGEEPrhKl4qOk/FlnS6j/i/T9rF/FWFCicc09N5qtHkoC+F2A8VNn creoDvfzeqDQ+ifaxNzFfP/9E8cS5AO4VvrIyLbjrmkv6UyeAEREdhTHu/DO/blPqkp9 jdog== X-Gm-Message-State: AFq9FYLh1HE7aaJcXWT+AlnF5EbIna8aUXN01nvFie+3SpqlO7XeVyCZ 4g0tzfQNf4VCLFF28CDpmiqKQGc3iuln6nKUDZNQJjNmnCuWaGOWFYqC7c7b8IL1PjIdFJBA7W9 yQfmwFwYZysr//1M1XGwvUcQQiD/HIUv3qJNzE2erLyJ04++Uw+0hxVkWWRs= X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-Received: by 2002:a05:6808:4f62:b0:4fb:6996:aac9 with SMTP id 5614622812f47-553580952bfmr4138273b6e.35.1792680791488; Thu, 22 Oct 2026 07:53:11 -0700 (PDT) Date: Thu, 22 Oct 2026 07:53:11 -0700 In-Reply-To: <6ad958f5.16f08417.1cb7b7.0001.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6ada2357.4c8f3b9a.1a805.0085.GAE@google.com> Subject: Forwarded: Re: [syzbot] [media?] [usb?] kernel BUG in v4l2_device_put From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: Re: [syzbot] [media?] [usb?] kernel BUG in v4l2_device_put Author: neganhat@gmail.com #syz test: linux-next 8f7df005a756 On Thu, Oct 22, 2026 at 9:08=E2=80=AFPM syzbot wrote: > > Hello, > > syzbot has tested the proposed patch but the reproducer is still triggeri= ng an issue: > KASAN: slab-use-after-free Read in v4l2_release > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > BUG: KASAN: slab-use-after-free in v4l2_device_supports_requests include/= media/v4l2-device.h:252 [inline] > BUG: KASAN: slab-use-after-free in v4l2_release+0xfe/0x350 drivers/media/= v4l2-core/v4l2-dev.c:466 > Read of size 8 at addr ffff888035785b10 by task v4l_id/7282 > > CPU: 1 UID: 0 PID: 7282 Comm: v4l_id Not tainted syzkaller #0 PREEMPT(ful= l) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS G= oogle 10/07/2026 > Call Trace: > > dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 > print_address_description+0x55/0x1e0 mm/kasan/report.c:378 > print_report+0x58/0x70 mm/kasan/report.c:482 > kasan_report+0x117/0x150 mm/kasan/report.c:595 > v4l2_device_supports_requests include/media/v4l2-device.h:252 [inline] > v4l2_release+0xfe/0x350 drivers/media/v4l2-core/v4l2-dev.c:466 > __fput+0x408/0xa40 fs/file_table.c:513 > fput_close_sync+0x11f/0x240 fs/file_table.c:619 > filp_close_sync fs/open.c:1897 [inline] > __do_sys_close fs/open.c:2153 [inline] > __se_sys_close+0xa2/0x160 fs/open.c:2140 > do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] > do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7f4a56ca7407 > Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 f= c 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80= 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff > RSP: 002b:00007ffcfee18b00 EFLAGS: 00000202 ORIG_RAX: 0000000000000003 > RAX: ffffffffffffffda RBX: 00007f4a57357880 RCX: 00007f4a56ca7407 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 > RBP: 00007f4a573576e8 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000013 > R13: 00007ffcfee18d30 R14: 00007f4a5745c000 R15: 0000557c8543f4d8 > > > Allocated by task 5749: > kasan_save_stack mm/kasan/common.c:57 [inline] > kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 > poison_kmalloc_redzone mm/kasan/common.c:409 [inline] > __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426 > kasan_kmalloc include/linux/kasan.h:263 [inline] > __kmalloc_cache_noprof+0x31c/0x600 mm/slub.c:5680 > _kmalloc_noprof include/linux/slab.h:991 [inline] > _kzalloc_noprof include/linux/slab.h:1312 [inline] > em28xx_media_device_init drivers/media/usb/em28xx/em28xx-cards.c:3757 [i= nline] > em28xx_init_dev+0x857/0x2680 drivers/media/usb/em28xx/em28xx-cards.c:394= 7 > em28xx_usb_probe+0x17b2/0x2dd0 drivers/media/usb/em28xx/em28xx-cards.c:4= 324 > usb_probe_interface+0x751/0xe00 drivers/usb/core/driver.c:399 > call_driver_probe drivers/base/dd.c:-1 [inline] > really_probe+0x254/0xae0 drivers/base/dd.c:707 > __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:869 > driver_probe_device+0x4f/0x240 drivers/base/dd.c:899 > __device_attach_driver+0x270/0x410 drivers/base/dd.c:1027 > bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:503 > __device_attach+0x2bd/0x430 drivers/base/dd.c:1131 > device_initial_probe+0x9c/0x100 drivers/base/dd.c:1190 > __bus_probe_device+0x126/0x220 drivers/base/bus.c:617 > device_add+0x7d7/0xb80 drivers/base/core.c:3776 > usb_set_configuration+0x1bb5/0x2260 drivers/usb/core/message.c:2280 > usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250 > usb_probe_device+0x1c3/0x3b0 drivers/usb/core/driver.c:293 > call_driver_probe drivers/base/dd.c:-1 [inline] > really_probe+0x254/0xae0 drivers/base/dd.c:707 > __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:869 > driver_probe_device+0x4f/0x240 drivers/base/dd.c:899 > __device_attach_driver+0x270/0x410 drivers/base/dd.c:1027 > bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:503 > __device_attach+0x2bd/0x430 drivers/base/dd.c:1131 > device_initial_probe+0x9c/0x100 drivers/base/dd.c:1190 > __bus_probe_device+0x126/0x220 drivers/base/bus.c:617 > device_add+0x7d7/0xb80 drivers/base/core.c:3776 > usb_new_device+0x9aa/0x1690 drivers/usb/core/hub.c:2713 > hub_port_connect drivers/usb/core/hub.c:5585 [inline] > hub_port_connect_change drivers/usb/core/hub.c:5725 [inline] > port_event drivers/usb/core/hub.c:5889 [inline] > hub_event+0x28e8/0x4d30 drivers/usb/core/hub.c:5971 > process_one_work kernel/workqueue.c:3495 [inline] > process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578 > worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659 > kthread+0x38b/0x480 kernel/kthread.c:436 > ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 > > Freed by task 5749: > kasan_save_stack mm/kasan/common.c:57 [inline] > kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 > kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 > poison_slab_object mm/kasan/common.c:264 [inline] > __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296 > kasan_slab_free include/linux/kasan.h:235 [inline] > slab_free_hook mm/slub.c:2780 [inline] > slab_free mm/slub.c:6630 [inline] > kfree+0x1c5/0x650 mm/slub.c:6923 > em28xx_unregister_media_device drivers/media/usb/em28xx/em28xx-cards.c:3= 779 [inline] > em28xx_release_resources+0xde/0x240 drivers/media/usb/em28xx/em28xx-card= s.c:3798 > em28xx_usb_disconnect+0x19f/0x2f0 drivers/media/usb/em28xx/em28xx-cards.= c:4493 > usb_unbind_interface+0x295/0x9c0 drivers/usb/core/driver.c:460 > device_remove drivers/base/dd.c:619 [inline] > __device_release_driver drivers/base/dd.c:1357 [inline] > device_release_driver_internal+0x48d/0x7d0 drivers/base/dd.c:1380 > bus_remove_device+0x444/0x560 drivers/base/bus.c:681 > device_del+0x524/0x8f0 drivers/base/core.c:3965 > usb_disable_device+0x3d4/0x8d0 drivers/usb/core/message.c:1484 > usb_disconnect+0x346/0x9a0 drivers/usb/core/hub.c:2355 > hub_port_connect drivers/usb/core/hub.c:5425 [inline] > hub_port_connect_change drivers/usb/core/hub.c:5725 [inline] > port_event drivers/usb/core/hub.c:5889 [inline] > hub_event+0x1bbb/0x4d30 drivers/usb/core/hub.c:5971 > process_one_work kernel/workqueue.c:3495 [inline] > process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578 > worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659 > kthread+0x38b/0x480 kernel/kthread.c:436 > ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 > > The buggy address belongs to the object at ffff888035785800 > which belongs to the cache kmalloc-1k of size 1024 > The buggy address is located 784 bytes inside of > freed 1024-byte region [ffff888035785800, ffff888035785c00) > > The buggy address belongs to the physical page: > page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3578= 0 > head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 > flags: 0xfff00000000040(head|node=3D0|zone=3D1|lastcpupid=3D0x7ff) > page_type: f5(slab) > raw: 00fff00000000040 ffff88813ff2bdc0 dead000000000100 dead000000000122 > raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 > head: 00fff00000000040 ffff88813ff2bdc0 dead000000000100 dead000000000122 > head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 > head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff > head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 > page dumped because: kasan: bad access detected > page_owner tracks the page as allocated > page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2820(= GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 162= , tgid 162 (kworker/u8:7), ts 176383093465 > set_page_owner include/linux/page_owner.h:33 [inline] > post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1856 > prep_new_page mm/page_alloc.c:1864 [inline] > get_page_from_freelist+0x220f/0x2280 mm/page_alloc.c:3935 > __alloc_frozen_pages_noprof+0x1fe/0x410 mm/page_alloc.c:5459 > alloc_slab_page mm/slub.c:3384 [inline] > allocate_slab+0x7d/0x5e0 mm/slub.c:3499 > new_slab mm/slub.c:3550 [inline] > refill_objects+0x2d5/0x350 mm/slub.c:7539 > refill_sheaf mm/slub.c:2917 [inline] > __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4811 > alloc_from_pcs mm/slub.c:4887 [inline] > slab_alloc_node mm/slub.c:5021 [inline] > __do_kmalloc_node mm/slub.c:5530 [inline] > __kmalloc_noprof+0x476/0x710 mm/slub.c:5556 > _kmalloc_noprof include/linux/slab.h:995 [inline] > _kzalloc_noprof include/linux/slab.h:1312 [inline] > ieee802_11_parse_elems_full+0x14b/0x2a10 net/mac80211/parse.c:1077 > ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2583 [inline] > ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1542 [inline] > ieee80211_ibss_rx_queued_mgmt+0x509/0x2c40 net/mac80211/ibss.c:1573 > ieee80211_iface_process_skb net/mac80211/iface.c:1805 [inline] > ieee80211_iface_work+0x769/0xfa0 net/mac80211/iface.c:1859 > cfg80211_wiphy_work+0x29e/0x420 net/wireless/core.c:610 > process_one_work kernel/workqueue.c:3495 [inline] > process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578 > worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659 > kthread+0x38b/0x480 kernel/kthread.c:436 > ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 > page last free pid 31 tgid 31 ts 176051931514 stack trace: > reset_page_owner include/linux/page_owner.h:26 [inline] > __free_pages_prepare mm/page_alloc.c:1403 [inline] > __free_frozen_pages+0xc97/0xd90 mm/page_alloc.c:2954 > __slab_free+0x269/0x2c0 mm/slub.c:5926 > qlink_free mm/kasan/quarantine.c:163 [inline] > qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 > kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 > __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:361 > kasan_slab_alloc include/linux/kasan.h:253 [inline] > slab_post_alloc_hook mm/slub.c:4720 [inline] > slab_alloc_node mm/slub.c:5033 [inline] > __kmalloc_cache_noprof+0x29a/0x600 mm/slub.c:5676 > _kmalloc_noprof include/linux/slab.h:991 [inline] > dummy_urb_enqueue+0x7c/0x7a0 drivers/usb/gadget/udc/dummy_hcd.c:1327 > usb_hcd_submit_urb+0x328/0x1b60 drivers/usb/core/hcd.c:1543 > usb_start_wait_urb+0x13f/0x5b0 drivers/usb/core/message.c:62 > usb_internal_control_msg drivers/usb/core/message.c:117 [inline] > usb_control_msg+0x234/0x3e0 drivers/usb/core/message.c:167 > get_bMaxPacketSize0 drivers/usb/core/hub.c:4869 [inline] > hub_port_init+0xb0b/0x28c0 drivers/usb/core/hub.c:5065 > hub_port_connect drivers/usb/core/hub.c:5514 [inline] > hub_port_connect_change drivers/usb/core/hub.c:5725 [inline] > port_event drivers/usb/core/hub.c:5889 [inline] > hub_event+0x24e8/0x4d30 drivers/usb/core/hub.c:5971 > process_one_work kernel/workqueue.c:3495 [inline] > process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578 > worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659 > kthread+0x38b/0x480 kernel/kthread.c:436 > ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 > > Memory state around the buggy address: > ffff888035785a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff888035785a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > >ffff888035785b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff888035785b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff888035785c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > > Tested on: > > commit: 8f7df005 Add linux-next specific files for 20261020 > git tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-= next.git > console output: https://syzkaller.appspot.com/x/log.txt?x=3D120a9fa958000= 0 > kernel config: https://syzkaller.appspot.com/x/.config?x=3D9c1b9b13e3e4c= e1a > dashboard link: https://syzkaller.appspot.com/bug?extid=3D809dfc586f33fc4= 4b6ac > compiler: Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.= 8 > patch: https://syzkaller.appspot.com/x/patch.diff?x=3D17b7b50d58= 0000 >