KASAN: use-after-free Read in release_card_device

Status: upstream: reported C repro on 2026/07/31 08:33
Reported-by: syzbot+7dd58bbfcf207cdb201d@syzkaller.appspotmail.com
First crash: 74d, last: 47d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2026/09/17 upstream (ToT) 4982d3552a3b syz Didn't crash
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in release_card_device prio:high sound 19 C 65 54d 69d 27/29 upstream: reported C repro on 2026/08/05 00:12
linux-5.15 KASAN: use-after-free Read in release_card_device 19 syz, C done 22 47d 54d 2/3 upstream: reported C repro on 2026/08/20 00:29
linux-6.6 KASAN: slab-use-after-free Read in release_card_device 19 syz, C error 8 47d 56d 0/2 upstream: reported C repro on 2026/08/18 04:57

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in snd_card_do_free sound/core/init.c:612 [inline]
BUG: KASAN: use-after-free in release_card_device+0x192/0x1a0 sound/core/init.c:145
Read of size 1 at addr ffff88802ebacd11 by task syz.3.97/4769

CPU: 0 PID: 4769 Comm: syz.3.97 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 snd_card_do_free sound/core/init.c:612 [inline]
 release_card_device+0x192/0x1a0 sound/core/init.c:145
 device_release+0x92/0x1c0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:681 [inline]
 kobject_release lib/kobject.c:712 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x217/0x450 lib/kobject.c:729
 snd_card_file_remove+0x32d/0x380 sound/core/init.c:1147
 snd_pcm_oss_release+0x1fd/0x240 sound/core/oss/pcm_oss.c:2597
 __fput+0x20a/0x8b0 fs/file_table.c:320
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc82599e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc82678a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffb3 RBX: 00007fc825c26090 RCX: 00007fc82599e0d9
RDX: 0000200000000080 RSI: 00000000c0045005 RDI: 0000000000000007
RBP: 00007fc825a35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc825c26128 R14: 00007fc825c26090 R15: 00007ffcd53e6a58
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0000baeb00 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2ebac
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001fd2c08 ffff8880b8e415f0 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 0x102800(GFP_NOWAIT|__GFP_NOWARN|__GFP_HARDWALL), pid 4773, tgid 4767 (syz.3.97), ts 142901623456, free_ts 142901661084
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560
 prep_new_page mm/page_alloc.c:2567 [inline]
 get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358
 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658
 __stack_depot_save+0x375/0x480 lib/stackdepot.c:474
 kasan_save_stack+0x4c/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
 task_work_add+0x7f/0x330 kernel/task_work.c:48
 fput+0xd9/0x1a0 fs/file_table.c:376
 fdput include/linux/file.h:47 [inline]
 fdput_pos include/linux/file.h:82 [inline]
 ksys_write+0x1fd/0x260 fs/read_write.c:640
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1487 [inline]
 free_pcp_prepare mm/page_alloc.c:1537 [inline]
 free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414
 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3509
 __stack_depot_save+0x44d/0x480 lib/stackdepot.c:506
 kasan_save_stack+0x4c/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
 task_work_add+0x7f/0x330 kernel/task_work.c:48
 fput+0xd9/0x1a0 fs/file_table.c:376
 fdput include/linux/file.h:47 [inline]
 fdput_pos include/linux/file.h:82 [inline]
 ksys_write+0x1fd/0x260 fs/read_write.c:640
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88802ebacc00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88802ebacc80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88802ebacd00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff88802ebacd80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88802ebace00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (47):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/26 11:36 linux-6.1.y 05208478041c 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/26 09:29 linux-6.1.y 05208478041c 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/25 07:21 linux-6.1.y 05208478041c 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/25 07:20 linux-6.1.y 05208478041c 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/24 21:06 linux-6.1.y 05208478041c b55bd4c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/22 04:15 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/21 02:50 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/21 01:07 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/21 01:04 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/21 01:01 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/20 02:31 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/18 09:21 linux-6.1.y e4f7d8be268e 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/18 09:21 linux-6.1.y e4f7d8be268e 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in release_card_device
2026/08/26 22:26 linux-6.1.y 05208478041c a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/26 19:07 linux-6.1.y 05208478041c a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/26 12:33 linux-6.1.y 05208478041c 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/26 12:33 linux-6.1.y 05208478041c 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/26 10:15 linux-6.1.y 05208478041c 6a91adb4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/26 07:20 linux-6.1.y 05208478041c 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/26 07:18 linux-6.1.y 05208478041c 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/25 06:10 linux-6.1.y 05208478041c 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/25 06:09 linux-6.1.y 05208478041c 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/25 06:09 linux-6.1.y 05208478041c 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/23 03:40 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/21 23:37 linux-6.1.y 7e6e67054721 1e72964b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/21 20:33 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/21 12:06 linux-6.1.y 7e6e67054721 1e72964b .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/21 08:51 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/20 21:08 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/20 21:07 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/20 16:29 linux-6.1.y 7e6e67054721 1e72964b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/20 13:48 linux-6.1.y 7e6e67054721 1e72964b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/20 05:57 linux-6.1.y 7e6e67054721 1e72964b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/20 05:05 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/20 05:03 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/19 23:03 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/19 23:03 linux-6.1.y 7e6e67054721 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/19 09:33 linux-6.1.y e4f7d8be268e 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/18 11:15 linux-6.1.y e4f7d8be268e 1e72964b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/18 06:06 linux-6.1.y e4f7d8be268e 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/18 06:06 linux-6.1.y e4f7d8be268e 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/08/08 14:32 linux-6.1.y e4f7d8be268e 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
2026/07/31 08:33 linux-6.1.y fb28aa725e05 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in release_card_device
* Struck through repros no longer work on HEAD.