From: syzbot <syzbot+7061d72c26b7daebe2b4@syzkaller.appspotmail.com>
To: linux-kernel@vger.kernel.org, linux-sound@vger.kernel.org,
perex@perex.cz, syzkaller-bugs@googlegroups.com, tiwai@suse.com
Subject: Re: [syzbot] [sound?] KASAN: use-after-free Read in release_card_device
Date: Thu, 13 Aug 2026 01:35:37 -0700 [thread overview]
Message-ID: <6a7d81d9.d5f0ebe7.22d851.0014.GAE@google.com> (raw)
In-Reply-To: <6a727fe7.13623e66.bdc14.003c.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 3d6d817622b0 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1729f479580000
kernel config: https://syzkaller.appspot.com/x/.config?x=aaf0da806f995318
dashboard link: https://syzkaller.appspot.com/bug?extid=7061d72c26b7daebe2b4
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=120e8ac6580000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7061d72c26b7daebe2b4@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in snd_card_do_free sound/core/init.c:604 [inline]
BUG: KASAN: use-after-free in release_card_device+0x1ab/0x1b0 sound/core/init.c:153
Read of size 1 at addr ffff8880331d8909 by task syz-executor144/6080
CPU: 0 UID: 0 PID: 6080 Comm: syz-executor144 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
<TASK>
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
snd_card_do_free sound/core/init.c:604 [inline]
release_card_device+0x1ab/0x1b0 sound/core/init.c:153
device_release+0xc4/0x1f0 drivers/base/core.c:-1
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x222/0x550 lib/kobject.c:737
snd_card_file_remove+0x331/0x390 sound/core/init.c:1125
snd_pcm_release+0x12c/0x160 sound/core/pcm_native.c:2986
__fput+0x418/0xa50 fs/file_table.c:512
fput_close_sync+0x11f/0x240 fs/file_table.c:617
__do_sys_close fs/open.c:1511 [inline]
__se_sys_close fs/open.c:1496 [inline]
__x64_sys_close+0x7e/0x110 fs/open.c:1496
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f26958f02de
Code: 08 0f 85 f5 e2 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 90 41 57 41 56 4d 89 c6 41 55 4d 89 cd 41 54 55 53 48 83 ec 08
RSP: 002b:00007f269508d118 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007f269508d6c0 RCX: 00007f26958f02de
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008
RBP: 00007f2695964d40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffd0
R13: 0000000000000002 R14: 00007ffe4c4b2ad0 R15: 00007ffe4c4b2bb8
</TASK>
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880331d9c00 pfn:0x331d8
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001c3d308 ffff8880b8641140 0000000000000000
raw: ffff8880331d9c00 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x40dc0(GFP_KERNEL|__GFP_ZERO|__GFP_COMP), pid 6065, tgid 6065 (syz-executor144), ts 116170038251, free_ts 116442889522
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859
prep_new_page mm/page_alloc.c:1867 [inline]
get_page_from_freelist+0x21fa/0x2270 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304
alloc_pages_mpol+0x212/0x380 mm/mempolicy.c:2490
___kmalloc_large_node+0x4c/0x120 mm/slub.c:5274
__kmalloc_large_node_noprof+0x18/0x90 mm/slub.c:5305
__do_kmalloc_node mm/slub.c:5322 [inline]
__kmalloc_node_track_caller_noprof+0x164/0x730 mm/slub.c:5471
alloc_dr drivers/base/devres.c:141 [inline]
__devres_alloc_node+0x4c/0x160 drivers/base/devres.c:189
snd_devm_card_new+0x84/0x160 sound/core/init.c:235
loopback_probe+0x150/0x13d0 sound/drivers/aloop.c:1805
platform_probe+0xf9/0x190 drivers/base/platform.c:1439
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x254/0xae0 drivers/base/dd.c:706
__driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
device_driver_attach+0xe0/0x1d0 drivers/base/dd.c:1203
bind_store+0x1d0/0x220 drivers/base/bus.c:267
kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345
page last free pid 6077 tgid 6065 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0xc1e/0xd10 mm/page_alloc.c:2950
free_node drivers/base/devres.c:50 [inline]
release_nodes drivers/base/devres.c:547 [inline]
devres_release_all+0x1ce/0x260 drivers/base/devres.c:576
device_unbind_cleanup drivers/base/dd.c:597 [inline]
__device_release_driver drivers/base/dd.c:1354 [inline]
device_release_driver_internal+0x5d9/0x880 drivers/base/dd.c:1372
unbind_store+0x1a1/0x1d0 drivers/base/bus.c:244
kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x612/0xba0 fs/read_write.c:687
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff8880331d8800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff8880331d8880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880331d8900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff8880331d8980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff8880331d8a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
next prev parent reply other threads:[~2026-08-13 8:35 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-05 0:12 [syzbot] [sound?] KASAN: use-after-free Read in release_card_device syzbot
2026-08-13 8:35 ` syzbot [this message]
2026-08-14 4:10 ` Hillf Danton
2026-08-14 7:37 ` syzbot
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