From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f77.google.com (mail-oa1-f77.google.com [209.85.160.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 603A234E766 for ; Mon, 1 Jun 2026 20:15:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780344934; cv=none; b=QhOOJu/w5mHVELTj5dnX9FNZOWKJgVCFbiNRs4kiBCrC57uxfomq9/8hEgcDtSklvSvHHDYclj8Rn2bR8O8w27OS2hxH3yrtfLytRbaxC87h56FIyYmycebLO16/dA7lv5ZLkTHMf/oWkrEOxGSgHoRcKEjaD8Vi00UuYpkkXZM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780344934; c=relaxed/simple; bh=+g254+7Qgx5n0xq8L9o1RNi399Qkf1w8zvUZZsEy6s8=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=OMkQ7WYQVXYkMWhmG8l5+ZGg5mrU04Tb98mjb8Ujnt9oLQ5Jb/vvU4jhxK7eAN2mYolL9EzqTWVTOprKuDd5dUobsOmJMDfpNy0rGRiqbJ0w5hqWtJbkorqavncEOyX+V9ZlWh1dEoZJFFkdOU1or+ckJm137uaD9HyzHO/5tNs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.160.77 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-oa1-f77.google.com with SMTP id 586e51a60fabf-43d1fa463d0so762869fac.0 for ; Mon, 01 Jun 2026 13:15:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780344932; x=1780949732; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=AbgNU9wV917JpgLW/r9KQyAbvW8yrBt6zmKcheEeKv0=; b=cCa3qvwlSNJg13Ypx/pGHgS0x7jfFarc8uBMuDMfYQZcNjCcf+RBBS5sZ9h+Ndv1Zx DmN/VbwfQlNSPMU6p6uVNl7Bfb4CKIOqs0ZaKNHoMKD5PBupZJMdITWGoFz1AKpXoQQk slh3u1b4/KMfYmphJ62R/Qbprizi9gCeGLM6Vf8VOfqEJ8wHl5kmnXp5XI79+NqX+S+D fcut9+pKff64tMzkROlxsGZJVZ/rVnacfg/euowtSCfSHIOdvQuykZ1yliw9M/BfByO1 W6DCs3mDknS49s6pAD9IUfY3RtGgW2MYONoUnY+tUflrPkfs4Tpd70UMdl+1U6F+fTfi 9RPw== X-Gm-Message-State: AOJu0YxJM0MUCKR7inVA1mXESmCD41vaPQNdWzW6cWZbpyzaHvwP8jkp xhV/RyZ17EyElN3rLhTn4679BA48QBR2aEObakWp9mTrk7ll/h8K0ExNZ6d/B+f7tiKgF2FmJjI /AGvPcYuP/WbIGPojZIg/1OJJ9dLedvztOW+dTZrmL9MwemFddWD+L61nff3QMQ== Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a4a:edc7:0:b0:69d:96c5:4e58 with SMTP id 006d021491bc7-69e1059eea5mr6241565eaf.28.1780344932373; Mon, 01 Jun 2026 13:15:32 -0700 (PDT) Date: Mon, 01 Jun 2026 13:15:32 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a1de864.278b5b03.2bcf39.003b.GAE@google.com> Subject: [syzbot] [media?] KASAN: slab-use-after-free Read in em28xx_v4l2_open From: syzbot To: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, mchehab@kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 6916d5703ddf Merge tag 'drm-fixes-2026-05-16' of https://g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14c53a73980000 kernel config: https://syzkaller.appspot.com/x/.config?x=4caf64b1ee83dac0 dashboard link: https://syzkaller.appspot.com/bug?extid=39ff299961a7c07f00f0 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/9b209d2c169e/disk-6916d570.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/260ba2c4b438/vmlinux-6916d570.xz kernel image: https://storage.googleapis.com/syzbot-assets/f62bb45b9b7e/bzImage-6916d570.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+39ff299961a7c07f00f0@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in dev_get_drvdata include/linux/device.h:927 [inline] BUG: KASAN: slab-use-after-free in video_get_drvdata include/media/v4l2-dev.h:491 [inline] BUG: KASAN: slab-use-after-free in video_drvdata include/media/v4l2-dev.h:523 [inline] BUG: KASAN: slab-use-after-free in em28xx_v4l2_open+0x57/0xa20 drivers/media/usb/em28xx/em28xx-video.c:2297 Read of size 8 at addr ffff8880655d8330 by task v4l_id/11714 CPU: 0 UID: 0 PID: 11714 Comm: v4l_id Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 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 dev_get_drvdata include/linux/device.h:927 [inline] video_get_drvdata include/media/v4l2-dev.h:491 [inline] video_drvdata include/media/v4l2-dev.h:523 [inline] em28xx_v4l2_open+0x57/0xa20 drivers/media/usb/em28xx/em28xx-video.c:2297 v4l2_open+0x1bf/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:433 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411 do_dentry_open+0x785/0x14e0 fs/open.c:947 vfs_open+0x3b/0x340 fs/open.c:1079 do_open fs/namei.c:4699 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4858 do_file_open+0x23e/0x4a0 fs/namei.c:4887 do_sys_openat2+0x113/0x200 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1381 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f23334a7407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 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:00007ffc786a3720 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f2333bc1880 RCX: 00007f23334a7407 RDX: 0000000000000000 RSI: 00007ffc786a4f1a RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffc786a3970 R14: 00007f2333d28000 R15: 000055bf73e474d8 Allocated by task 24475: 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:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5419 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] em28xx_v4l2_init+0x10b/0x2eb0 drivers/media/usb/em28xx/em28xx-video.c:2707 em28xx_init_extension+0x120/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1248 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x389/0x470 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 24475: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free mm/slub.c:6250 [inline] kfree+0x1c5/0x640 mm/slub.c:6565 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2287 [inline] kref_put include/linux/kref.h:65 [inline] em28xx_v4l2_init+0x1685/0x2eb0 drivers/media/usb/em28xx/em28xx-video.c:3078 em28xx_init_extension+0x120/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1248 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x389/0x470 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 ffff8880655d8000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 816 bytes inside of freed 8192-byte region [ffff8880655d8000, ffff8880655da000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880655dc000 pfn:0x655d8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88813fe1b280 ffffea0001ddbc10 ffff88813fe19ac8 raw: ffff8880655dc000 0000000800020001 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88813fe1b280 ffffea0001ddbc10 ffff88813fe19ac8 head: ffff8880655dc000 0000000800020001 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 24475, tgid 24475 (kworker/0:1), ts 2367631693947, free_ts 2367608772413 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1866 [inline] get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab+0x77/0x660 mm/slub.c:3467 new_slab mm/slub.c:3525 [inline] refill_objects+0x339/0x3d0 mm/slub.c:7271 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4651 alloc_from_pcs mm/slub.c:4749 [inline] slab_alloc_node mm/slub.c:4883 [inline] __kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5414 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] em28xx_v4l2_init+0x10b/0x2eb0 drivers/media/usb/em28xx/em28xx-video.c:2707 em28xx_init_extension+0x120/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1248 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x389/0x470 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 19335 tgid 19335 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1402 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943 __slab_free+0x274/0x2c0 mm/slub.c:5612 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:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] __kmalloc_cache_noprof+0x2ba/0x660 mm/slub.c:5414 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] vidtv_s302m_access_unit_init drivers/media/test-drivers/vidtv/vidtv_s302m.c:151 [inline] vidtv_s302m_alloc_au drivers/media/test-drivers/vidtv/vidtv_s302m.c:198 [inline] vidtv_s302m_encode+0x367/0x1880 drivers/media/test-drivers/vidtv/vidtv_s302m.c:408 vidtv_mux_poll_encoders drivers/media/test-drivers/vidtv/vidtv_mux.c:333 [inline] vidtv_mux_tick+0x1358/0x24e0 drivers/media/test-drivers/vidtv/vidtv_mux.c:410 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x389/0x470 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 Memory state around the buggy address: ffff8880655d8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880655d8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880655d8300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880655d8380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880655d8400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup