[syzbot] [sound?] KASAN: use-after-free Read in release_card_device

[syzbot] [sound?] KASAN: use-after-free Read in release_card_device

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    0131b508c0e2 Merge tag 'ntfs-for-7.2-rc6' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=109f4c9e580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=7061d72c26b7daebe2b4
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/237b6b227f6e/disk-0131b508.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/90a5294c2a5d/vmlinux-0131b508.xz
kernel image: https://storage.googleapis.com/syzbot-assets/54d17924c110/bzImage-0131b508.xz

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+0x17d/0x1a0 sound/core/init.c:153
Read of size 1 at addr ffff88814a70c909 by task syz.5.630/8206

CPU: 0 UID: 0 PID: 8206 Comm: syz.5.630 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 lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 snd_card_do_free sound/core/init.c:604 [inline]
 release_card_device+0x17d/0x1a0 sound/core/init.c:153
 device_release+0xd2/0x270 drivers/base/core.c:2636
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1f7/0x640 lib/kobject.c:737
 put_device+0x1f/0x30 drivers/base/core.c:3880
 snd_card_file_remove+0x38f/0x560 sound/core/init.c:1125
 snd_pcm_oss_release+0x217/0x300 sound/core/oss/pcm_oss.c:2596
 __fput+0x3ff/0xb50 fs/file_table.c:512
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x951/0x2ae0 kernel/exit.c:1009
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1152
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3046
 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0x139/0x6f0 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x666/0x870 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f883d59e019
Code: Unable to access opcode bytes at 0x7f883d59dfef.
RSP: 002b:00007f883e4a40e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f883d825fa8 RCX: 00007f883d59e019
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f883d825fa8
RBP: 00007f883d825fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f883d826038 R14: 00007fff416628d0 R15: 00007fff416629b8
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14a70c
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000000 ffff8880b8541800 ffff8880b8541800 0000000000000000
raw: 0000000000000000 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 1, tgid 1 (swapper/0), ts 17137786410, free_ts 237675753363
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_pages_mpol+0x1fb/0x540 mm/mempolicy.c:2490
 ___kmalloc_large_node+0xe5/0x120 mm/slub.c:5274
 __kmalloc_large_node_noprof+0x1c/0x70 mm/slub.c:5305
 __do_kmalloc_node mm/slub.c:5322 [inline]
 __kmalloc_node_track_caller_noprof+0x5ac/0x830 mm/slub.c:5471
 alloc_dr drivers/base/devres.c:141 [inline]
 __devres_alloc_node+0x6e/0x1e0 drivers/base/devres.c:189
 snd_devm_card_new+0x9d/0x190 sound/core/init.c:235
 loopback_probe+0x140/0x11a0 sound/drivers/aloop.c:1805
 platform_probe+0x106/0x1d0 drivers/base/platform.c:1439
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
 __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
page last free pid 8220 tgid 8219 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 free_node drivers/base/devres.c:50 [inline]
 release_nodes+0xc3/0x120 drivers/base/devres.c:547
 devres_release_all+0x112/0x180 drivers/base/devres.c:576
 device_unbind_cleanup+0x81/0x270 drivers/base/dd.c:597
 __device_release_driver drivers/base/dd.c:1354 [inline]
 device_release_driver_internal+0x4c4/0x620 drivers/base/dd.c:1372
 unbind_store+0xf8/0x110 drivers/base/bus.c:244
 drv_attr_store+0x74/0xb0 drivers/base/bus.c:125
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88814a70c800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88814a70c880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88814a70c900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                      ^
 ffff88814a70c980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88814a70ca00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


---
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Re: [syzbot] [sound?] KASAN: use-after-free Read in release_card_device

[syzbot]

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.

Re: [syzbot] [sound?] KASAN: use-after-free Read in release_card_device

[Hillf Danton]

> Date: Thu, 13 Aug 2026 01:35:37 -0700	[thread overview]
> 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
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=120e8ac6580000

#syz test

--- x/sound/core/init.c
+++ y/sound/core/init.c
@@ -599,8 +599,10 @@ static int snd_card_do_free(struct snd_c
 		dev_warn(card->dev, "unable to free card info\n");
 		/* Not fatal error */
 	}
-	if (card->release_completion)
+	if (card->release_completion) {
 		complete(card->release_completion);
+		return 0;
+	}
 	if (!card->managed)
 		kfree(card);
 	return 0;
--

Re: [syzbot] [sound?] KASAN: use-after-free Read in release_card_device

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+7061d72c26b7daebe2b4@syzkaller.appspotmail.com
Tested-by: syzbot+7061d72c26b7daebe2b4@syzkaller.appspotmail.com

Tested on:

commit:         2f1baf1f Merge tag 'trace-v7.2-rc7' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12a73a9e580000
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
patch:          https://syzkaller.appspot.com/x/patch.diff?x=17585279580000

Note: testing is done by a robot and is best-effort only.