KASAN: use-after-free Read in release_card_device

Status: upstream: reported on 2026/07/31 08:33
Reported-by: syzbot+7dd58bbfcf207cdb201d@syzkaller.appspotmail.com
First crash: 15d, last: 7d09h
Similar bugs (1)
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 27 2d07h 10d 0/29 upstream: reported C repro on 2026/08/05 00:12

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+0x188/0x198 sound/core/init.c:145
Read of size 1 at addr ffff0000d5af0d99 by task syz.5.883/8729

CPU: 1 PID: 8729 Comm: syz.5.883 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
Call trace:
 dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0xfc mm/kasan/report.c:524
 __asan_report_load1_noabort+0x2c/0x38 mm/kasan/report_generic.c:348
 snd_card_do_free sound/core/init.c:612 [inline]
 release_card_device+0x188/0x198 sound/core/init.c:145
 device_release+0x94/0x1b4 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+0x2a8/0x41c lib/kobject.c:729
 put_device+0x28/0x40 drivers/base/core.c:3820
 snd_card_file_remove+0x2e4/0x340 sound/core/init.c:1147
 snd_pcm_oss_release+0x1e4/0x230 sound/core/oss/pcm_oss.c:2597
 snd_disconnect_release+0x224/0x298 sound/core/init.c:438
 __fput+0x1b4/0x7b0 fs/file_table.c:320
 ____fput+0x20/0x30 fs/file_table.c:348
 task_work_run+0x1f4/0x280 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 do_notify_resume+0x20f8/0x2c84 arch/arm64/kernel/signal.c:1151
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x98/0x128 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the physical page:
page:00000000d2878eb5 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x115af0
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 fffffc0003497808 ffff00019f3ce0b0 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d5af0c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000d5af0d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff0000d5af0d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff0000d5af0e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000d5af0e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.