KASAN: use-after-free Read in release_card_device

Status: upstream: reported C repro on 2026/08/05 00:12
Subsystems: sound
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+7061d72c26b7daebe2b4@syzkaller.appspotmail.com
Fix commit: 5ae1a690c522 ALSA: core: Fix use-after-free in snd_card_do_free()
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci-upstream-rust-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu2-arm32 ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root]
First crash: 54d, last: 34d
▶ ▼ ✨ AI Patch Versions (2)
Version Stage Reported Report Link Job
1 upstream 2026/08/14 12:05 Discussion 24752a23-f0b6-49c1-bf20-4fa89c2e7eb2
1 moderation 2026/08/13 19:56 Discussion 24752a23-f0b6-49c1-bf20-4fa89c2e7eb2
▶ ▼ ✨ AI Jobs (4)
ID Workflow Result Correct Bug Created Started Finished Revision
24752a23 patching ✅ KASAN: use-after-free Read in release_card_device 2026/08/13 11:33 2026/08/13 18:20 2026/08/13 19:56 0165196a
e126d0f2 repro-c Reproduced: ✅ ❓ KASAN: use-after-free Read in release_card_device 2026/08/12 12:00 2026/08/12 12:53 2026/08/12 14:11 f8d35649
87857e6e repro-c Reproduced: ✅ ❓ KASAN: use-after-free Read in release_card_device 2026/08/06 11:00 2026/08/07 07:40 2026/08/07 08:39 c38879ea
81910ecc assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: use-after-free Read in release_card_device 2026/08/02 00:33 2026/08/02 00:33 2026/08/02 01:05 e611ffe1
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[PATCH] ALSA: core: Fix use-after-free in snd_card_do_free() 2 (2) 2026/08/14 12:14
[syzbot] [sound?] KASAN: use-after-free Read in release_card_device 1 (4) 2026/08/14 07:37
[syzbot] Monthly sound report (Aug 2026) 0 (1) 2026/08/08 04:32
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 KASAN: use-after-free Read in release_card_device 19 syz, C 22 27d 35d 0/3 upstream: reported C repro on 2026/08/20 00:29
linux-6.1 KASAN: use-after-free Read in release_card_device 19 syz, C 47 28d 54d 0/3 upstream: reported C repro on 2026/07/31 08:33
linux-6.6 KASAN: slab-use-after-free Read in release_card_device 19 syz, C 8 27d 36d 0/2 upstream: reported C repro on 2026/08/18 04:57
▶ ▼ Last patch testing requests (3)
Created Duration User Patch Repo Result
2026/08/14 04:10 17m hdanton@sina.com patch upstream OK job log log
2026/08/13 07:48 27m nogikh@google.com upstream report job log log
2026/08/07 08:48 18m glider@google.com upstream error

Sample crash report:
==================================================================
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
==================================================================

Crashes (65):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/13 08:34 upstream 3d6d817622b0 e4ef95d6 .config console log report C ci-upstream-kasan-gce-root KASAN: use-after-free Read in release_card_device
2026/08/20 00:04 upstream bd5f485f3f02 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: use-after-free Read in release_card_device
2026/08/19 21:16 upstream bd5f485f3f02 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: use-after-free Read in release_card_device
2026/08/18 02:53 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: use-after-free Read in release_card_device
2026/08/18 02:53 upstream 8d3ae59288f1 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: use-after-free Read in release_card_device
2026/08/17 13:24 upstream 8d3ae59288f1 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: use-after-free Read in release_card_device
2026/08/17 11:10 upstream 8d3ae59288f1 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: use-after-free Read in release_card_device
2026/08/13 15:55 upstream 3d6d817622b0 a9ede23c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: use-after-free Read in release_card_device
2026/08/07 17:17 upstream 364465ab19de e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: use-after-free Read in release_card_device
2026/08/07 17:16 upstream 364465ab19de e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: use-after-free Read in release_card_device
2026/08/01 06:03 upstream 0131b508c0e2 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: use-after-free Read in release_card_device
2026/08/01 03:03 upstream 8ba098e6b6ff 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: use-after-free Read in release_card_device
2026/08/20 04:36 upstream bd5f485f3f02 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/20 01:21 upstream bd5f485f3f02 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/19 23:02 upstream bd5f485f3f02 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/19 09:25 upstream b126f6f5940f 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in release_card_device
2026/08/18 10:21 upstream ff68e5f557f6 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/18 02:51 upstream ff68e5f557f6 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/18 02:46 upstream ff68e5f557f6 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/18 02:42 upstream ff68e5f557f6 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in release_card_device
2026/08/18 02:42 upstream ff68e5f557f6 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in release_card_device
2026/08/17 11:11 upstream 8d3ae59288f1 905244d6 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in release_card_device
2026/08/17 11:11 upstream 8d3ae59288f1 905244d6 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in release_card_device
2026/08/17 11:11 upstream 8d3ae59288f1 905244d6 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in release_card_device
2026/08/17 11:11 upstream 8d3ae59288f1 905244d6 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in release_card_device
2026/08/17 09:27 upstream 8d3ae59288f1 905244d6 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/13 15:15 upstream 3d6d817622b0 4d118901 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in release_card_device
2026/08/13 15:15 upstream 3d6d817622b0 4d118901 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in release_card_device
2026/08/13 00:22 upstream 3d6d817622b0 359b2492 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in release_card_device
2026/08/11 01:30 upstream d58772d8520c 508909ea .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/10 09:36 upstream db2ddb871435 558388e4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/10 04:24 upstream b643e495ae92 5d63f80b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/09 22:01 upstream b643e495ae92 5d63f80b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/09 20:58 upstream b643e495ae92 5d63f80b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/06 16:16 upstream 0d8395707651 cc56899a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/05 13:25 upstream c21bb4193868 1eed00d1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/03 21:24 upstream 075b74841bd0 bdd50915 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/03 20:03 upstream 075b74841bd0 bdd50915 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in release_card_device
2026/08/03 20:03 upstream 075b74841bd0 bdd50915 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in release_card_device
2026/08/02 07:47 upstream 2d2338c93da7 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/02 06:48 upstream 2d2338c93da7 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: use-after-free Read in release_card_device
2026/08/19 18:56 upstream bd5f485f3f02 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: use-after-free Read in release_card_device
2026/08/19 13:20 upstream b126f6f5940f 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: use-after-free Read in release_card_device
2026/08/19 03:23 upstream b126f6f5940f 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: use-after-free Read in release_card_device
2026/08/17 12:10 upstream 8d3ae59288f1 905244d6 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: use-after-free Read in release_card_device
2026/08/08 11:10 upstream 3f008280327b 5d63f80b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: use-after-free Read in release_card_device
2026/08/08 06:15 upstream 3f008280327b 5d63f80b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: use-after-free Read in release_card_device
2026/08/02 16:11 upstream 2d2338c93da7 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: use-after-free Read in release_card_device
2026/07/31 18:57 upstream 8ba098e6b6ff db462e94 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: use-after-free Read in release_card_device
2026/07/31 16:13 upstream 8ba098e6b6ff db462e94 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: use-after-free Read in release_card_device
2026/08/12 02:47 linux-next 5e6de6a2b522 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in release_card_device
2026/08/19 17:49 upstream bd5f485f3f02 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-out-of-bounds Read in release_card_device
* Struck through repros no longer work on HEAD.