From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f78.google.com (mail-oo1-f78.google.com [209.85.161.78]) (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 94D923A783D for ; Tue, 20 Jan 2026 20:09:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768939775; cv=none; b=ZGcMC8NXkCkN+g7UwOgeM//Xd60ZpmJKUVKX+iHRqmgaZFbZ75C7Dw4KyN+zv26oGAaiGGRRoWZ+Xl2OPRgUoyEN1F6sZfVh7IhMqVa7zJmTRcCe0Rcgzs8w4u14T2UnN6HhlzuzrkJK8mJV0EW1PiWK1nhmvlfVqO4O9z7ujGE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768939775; c=relaxed/simple; bh=RZAZOcFftgqiOUqdetZ4qJufpsPtVj4pn7RSezgEOqA=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=Ych2J6BYrHyZhnXGyl4RNr14nGxzGHY95XFelkjYyKfWHTNGbCANfMHeLwuGnxdZoDNSQpYkvV5wp+cVYco5Jx4LuMJQ4PWcG6N6zpTVy0Wmdw7R28HV5UpmKl5e/byWaqTJRwAv0s76hEKlo5Qko2J+mkMHc0iAR9wUEsJIPwo= 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=209.85.161.78 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-oo1-f78.google.com with SMTP id 006d021491bc7-65f7130d6aeso13807319eaf.0 for ; Tue, 20 Jan 2026 12:09:33 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768939772; x=1769544572; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=+JyllCYGHWtGpqdkbEf3fWZjzQT6BUA8wzTUSY8dsow=; b=RH24yO58SbJNQvhaA2jc4HrC6Sw/ZdbHQRXi9cAq5N+QFPK3CS9TPLpG2KVfu7t3Fw jfG+FOng6p4/eDl3oQWsrJdXq93u7vjSfNomdYwOBIiTcAsMQVrYkLO9WIJkqVmlwogq hO43msK9vZ2vd1o9vSzvwqYM9cXN/V29pw94Rad69eXriCaR6TsU+dCmSNJc+5wyz4Lt vOKQTTUTRBJLPHP6hNvpUvTFaoyEJKYoWKt4ZBP9S1DEVZXpDiWN8myHSlKaZ1Z2Myhj KJTiuZllXi3t6WYIQa0ZoJGofGTVIwH3b6hWybQ9X4NspFpcaGOt3dXR1UPgDz62MLkh dkpQ== X-Gm-Message-State: AOJu0YxSAoPMN4v04hFL65Lmsrz7IBkg1a7KvPGIxgvfk6CWVy/M+tb/ 79jZ2coByDdcRkWVZHbTzEYG7tHHUEjGHwYoMZt2Gb906wSZam2Cixi5zajM1TBqZowrGS8j241 ozRuHOR/5HJcfbZ0HuSkxnTIQK0/dhWqwxSqoxLyow/a46trM2YQr8GUXhQnOfg== Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4a0d:b0:659:9a49:8f9a with SMTP id 006d021491bc7-661188e745amr4701684eaf.19.1768939772459; Tue, 20 Jan 2026 12:09:32 -0800 (PST) Date: Tue, 20 Jan 2026 12:09:32 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <696fe0fc.050a0220.706b.0001.GAE@google.com> Subject: [syzbot] [sound?] KASAN: slab-use-after-free Read in snd_pcm_post_stop From: syzbot To: linux-kernel@vger.kernel.org, linux-sound@vger.kernel.org, perex@perex.cz, syzkaller-bugs@googlegroups.com, tiwai@suse.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: e84d960149e7 Merge tag 'for-6.19-rc5-tag' of git://git.ker.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15277522580000 kernel config: https://syzkaller.appspot.com/x/.config?x=7b058fb1d7dbe6b1 dashboard link: https://syzkaller.appspot.com/bug?extid=16b2b67ae905feb8a289 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/09af5f7a987e/disk-e84d9601.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/9b42fe73e088/vmlinux-e84d9601.xz kernel image: https://storage.googleapis.com/syzbot-assets/37e4d5c70177/bzImage-e84d9601.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+16b2b67ae905feb8a289@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in rt_spin_lock+0x88/0x3e0 kernel/locking/spinlock_rt.c:56 Read of size 1 at addr ffff88802fee8170 by task syz.0.79/6271 CPU: 1 UID: 0 PID: 6271 Comm: syz.0.79 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:574 kasan_check_byte include/linux/kasan.h:402 [inline] lock_acquire+0x84/0x340 kernel/locking/lockdep.c:5842 rt_spin_lock+0x88/0x3e0 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:44 [inline] __wake_up_common_lock+0x2f/0x1e0 kernel/sched/wait.c:124 snd_pcm_post_stop+0x14a/0x1e0 sound/core/pcm_native.c:1550 snd_pcm_action_single sound/core/pcm_native.c:-1 [inline] snd_pcm_action+0x1f4/0x240 sound/core/pcm_native.c:1398 loopback_check_format sound/drivers/aloop.c:363 [inline] loopback_trigger+0xb82/0x1b60 sound/drivers/aloop.c:411 snd_pcm_do_start+0xb7/0x180 sound/core/pcm_native.c:1459 snd_pcm_action_single sound/core/pcm_native.c:1315 [inline] snd_pcm_action+0xe7/0x240 sound/core/pcm_native.c:1398 __snd_pcm_lib_xfer+0x1762/0x1d00 sound/core/pcm_lib.c:2405 snd_pcm_oss_write3+0x1bc/0x350 sound/core/oss/pcm_oss.c:1243 snd_pcm_plug_write_transfer+0x2cb/0x4c0 sound/core/oss/pcm_plugin.c:630 snd_pcm_oss_write2 sound/core/oss/pcm_oss.c:1375 [inline] snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1441 [inline] snd_pcm_oss_write+0xa31/0xf20 sound/core/oss/pcm_oss.c:2796 vfs_write+0x287/0xb40 fs/read_write.c:684 ksys_write+0x14b/0x260 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0e7667f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0e748a4038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f0e768d6180 RCX: 00007f0e7667f749 RDX: 0000000000004000 RSI: 00002000000012c0 RDI: 0000000000000007 RBP: 00007f0e76703f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0e768d6218 R14: 00007f0e768d6180 R15: 00007ffe1e187e28 Allocated by task 6270: 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+0x1fb/0x6d0 mm/slub.c:5776 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] snd_pcm_attach_substream+0x5b7/0xb30 sound/core/pcm.c:938 snd_pcm_open_substream+0xb6/0x2410 sound/core/pcm_native.c:2761 snd_pcm_oss_open_file sound/core/oss/pcm_oss.c:2439 [inline] snd_pcm_oss_open+0xf2a/0x1bd0 sound/core/oss/pcm_oss.c:2520 chrdev_open+0x4cf/0x5e0 fs/char_dev.c:414 do_dentry_open+0x7d0/0x1270 fs/open.c:962 vfs_open+0x3b/0x350 fs/open.c:1094 do_open fs/namei.c:4637 [inline] path_openat+0x342a/0x3df0 fs/namei.c:4796 do_filp_open+0x1fa/0x410 fs/namei.c:4823 do_sys_openat2+0x121/0x200 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1447 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6268: 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:2540 [inline] slab_free mm/slub.c:6670 [inline] kfree+0x1bd/0x900 mm/slub.c:6878 snd_pcm_detach_substream+0x1e1/0x290 sound/core/pcm.c:1003 snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2398 [inline] snd_pcm_oss_release+0x184/0x250 sound/core/oss/pcm_oss.c:2577 __fput+0x45b/0xa80 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:44 [inline] exit_to_user_mode_loop+0xef/0x4e0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802fee8000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 368 bytes inside of freed 2048-byte region [ffff88802fee8000, ffff88802fee8800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2fee8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x80000000000040(head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122 head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 0080000000000003 ffffea0000bfba01 00000000ffffffff 00000000ffffffff head: 0000000000000000 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 12, tgid 12 (kworker/u8:0), ts 112751171195, free_ts 112474179646 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1884 prep_new_page mm/page_alloc.c:1892 [inline] get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3945 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5240 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab+0x86/0x3b0 mm/slub.c:3248 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xb10/0x13e0 mm/slub.c:4656 __slab_alloc+0xc6/0x1f0 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kmalloc_node_track_caller_noprof+0x2bf/0x810 mm/slub.c:5764 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:608 __alloc_skb+0x204/0x3a0 net/core/skbuff.c:690 alloc_skb include/linux/skbuff.h:1383 [inline] mld_newpack+0x13c/0xc40 net/ipv6/mcast.c:1775 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1886 add_grec+0x1452/0x1740 net/ipv6/mcast.c:2025 mld_send_initial_cr+0x288/0x550 net/ipv6/mcast.c:2268 ipv6_mc_dad_complete+0x88/0x410 net/ipv6/mcast.c:2279 addrconf_dad_completed+0x58d/0xd70 net/ipv6/addrconf.c:4340 page last free pid 5166 tgid 5166 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0xfe1/0x1170 mm/page_alloc.c:2973 discard_slab mm/slub.c:3346 [inline] __put_partials+0x149/0x170 mm/slub.c:3886 __slab_free+0x2af/0x330 mm/slub.c:5952 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 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:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kvmalloc_node_noprof+0x3b4/0x940 mm/slub.c:7136 seq_buf_alloc fs/seq_file.c:38 [inline] seq_read_iter+0x203/0xe20 fs/seq_file.c:210 new_sync_read fs/read_write.c:491 [inline] vfs_read+0x563/0xa30 fs/read_write.c:572 ksys_read+0x14b/0x260 fs/read_write.c:715 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88802fee8000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802fee8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802fee8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802fee8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802fee8200: 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