[syzbot] [sound?] KASAN: slab-use-after-free Read in snd_pcm_action
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syzbot
Oct 21, 2025, 6:48:33 AM10/21/25
to linux-...@vger.kernel.org, linux...@vger.kernel.org, pe...@perex.cz, syzkall...@googlegroups.com, ti...@suse.com
Hello,
syzbot found the following issue on:
HEAD commit: 211ddde0823f Linux 6.18-rc2
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16304e7c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=216353986aa62c5d
dashboard link: https://syzkaller.appspot.com/bug?extid=addf1973f8732e2cc468
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/07371cf02d4e/disk-211ddde0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/27220c94ca08/vmlinux-211ddde0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/12abd01b8291/bzImage-211ddde0.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+addf19...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
Read of size 1 at addr ffff8880338ae1c0 by task syz.7.3131/20318
CPU: 0 UID: 0 PID: 20318 Comm: syz.7.3131 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
__kasan_check_byte+0x2a/0x40 mm/kasan/common.c:580
kasan_check_byte include/linux/kasan.h:401 [inline]
lock_acquire+0x8d/0x360 kernel/locking/lockdep.c:5842
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
rtlock_slowlock kernel/locking/rtmutex.c:1894 [inline]
rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
__rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
rt_spin_lock+0x14a/0x3e0 kernel/locking/spinlock_rt.c:57
spin_lock include/linux/spinlock_rt.h:44 [inline]
__wake_up_common_lock+0x2f/0x1e0 kernel/sched/wait.c:124
snd_pcm_action_single sound/core/pcm_native.c:-1 [inline]
snd_pcm_action+0x1f4/0x240 sound/core/pcm_native.c:1393
loopback_check_format sound/drivers/aloop.c:363 [inline]
loopback_trigger+0xb82/0x1b60 sound/drivers/aloop.c:411
snd_pcm_do_start+0xb7/0x180 sound/core/pcm_native.c:1454
snd_pcm_action_single sound/core/pcm_native.c:1310 [inline]
snd_pcm_action+0xe7/0x240 sound/core/pcm_native.c:1393
__snd_pcm_lib_xfer+0x1762/0x1ce0 sound/core/pcm_lib.c:2405
snd_pcm_oss_write3+0x1bc/0x320 sound/core/oss/pcm_oss.c:1241
snd_pcm_plug_write_transfer+0x2cb/0x4c0 sound/core/oss/pcm_plugin.c:630
snd_pcm_oss_write2 sound/core/oss/pcm_oss.c:1373 [inline]
snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1439 [inline]
snd_pcm_oss_write+0xba2/0x11a0 sound/core/oss/pcm_oss.c:2794
vfs_write+0x287/0xb40 fs/read_write.c:684
ksys_write+0x14b/0x260 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd64e82efc9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd64ca75038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd64ea86090 RCX: 00007fd64e82efc9
RDX: 0000000000004000 RSI: 00002000000012c0 RDI: 0000000000000005
RBP: 00007fd64e8b1f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd64ea86128 R14: 00007fd64ea86090 R15: 00007ffd87fbae38
</TASK>
Allocated by task 20315:
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417
kasan_kmalloc include/linux/kasan.h:262 [inline]
__kmalloc_cache_noprof+0x1ef/0x6c0 mm/slub.c:5755
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
snd_pcm_attach_substream+0x5b7/0xb50 sound/core/pcm.c:938
snd_pcm_open_substream+0xb9/0x23a0 sound/core/pcm_native.c:2756
snd_pcm_oss_open_file sound/core/oss/pcm_oss.c:2437 [inline]
snd_pcm_oss_open+0xf35/0x1bf0 sound/core/oss/pcm_oss.c:2518
chrdev_open+0x4cf/0x5e0 fs/char_dev.c:414
do_dentry_open+0x9b1/0x1350 fs/open.c:965
vfs_open+0x3b/0x350 fs/open.c:1097
do_open fs/namei.c:3975 [inline]
path_openat+0x2ef1/0x3840 fs/namei.c:4134
do_filp_open+0x1fa/0x410 fs/namei.c:4161
do_sys_openat2+0x121/0x1c0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 20314:
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
__kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587
kasan_save_free_info mm/kasan/kasan.h:406 [inline]
poison_slab_object mm/kasan/common.c:252 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2530 [inline]
slab_free mm/slub.c:6619 [inline]
kfree+0x197/0x950 mm/slub.c:6826
snd_pcm_detach_substream+0x1e1/0x290 sound/core/pcm.c:1003
snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2396 [inline]
snd_pcm_oss_release+0x184/0x250 sound/core/oss/pcm_oss.c:2575
__fput+0x45b/0xa80 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff8880338ae000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 448 bytes inside of
freed 2048-byte region [ffff8880338ae000, ffff8880338ae800)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x338a8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea0000ce2a01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5810, tgid 5810 (syz-executor), ts 87951115432, free_ts 83939004793
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850
prep_new_page mm/page_alloc.c:1858 [inline]
get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3884
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
alloc_slab_page mm/slub.c:3046 [inline]
allocate_slab+0x96/0x3a0 mm/slub.c:3219
new_slab mm/slub.c:3273 [inline]
___slab_alloc+0xb12/0x13f0 mm/slub.c:4643
__slab_alloc+0xc6/0x1f0 mm/slub.c:4762
__slab_alloc_node mm/slub.c:4838 [inline]
slab_alloc_node mm/slub.c:5260 [inline]
__do_kmalloc_node mm/slub.c:5633 [inline]
__kmalloc_node_track_caller_noprof+0x2a8/0x7e0 mm/slub.c:5743
kmalloc_reserve+0x136/0x290 net/core/skbuff.c:601
__alloc_skb+0x142/0x2d0 net/core/skbuff.c:670
alloc_skb include/linux/skbuff.h:1383 [inline]
nlmsg_new include/net/netlink.h:1055 [inline]
rtmsg_ifinfo_build_skb+0x84/0x260 net/core/rtnetlink.c:4400
rtmsg_ifinfo_event net/core/rtnetlink.c:4442 [inline]
rtmsg_ifinfo+0x8c/0x1a0 net/core/rtnetlink.c:4451
register_netdevice+0x1746/0x1b10 net/core/dev.c:11346
__ip_tunnel_create+0x3e7/0x560 net/ipv4/ip_tunnel.c:268
ip_tunnel_init_net+0x2ba/0x800 net/ipv4/ip_tunnel.c:1147
ops_init+0x35c/0x5c0 net/core/net_namespace.c:137
page last free pid 5784 tgid 5784 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
__free_frozen_pages+0xfb6/0x1140 mm/page_alloc.c:2906
__folio_put+0x247/0x300 mm/swap.c:112
put_netmem net/core/skbuff.c:7376 [inline]
skb_page_unref include/linux/skbuff_ref.h:43 [inline]
__skb_frag_unref include/linux/skbuff_ref.h:56 [inline]
skb_release_data+0x49a/0x7c0 net/core/skbuff.c:1081
skb_release_all net/core/skbuff.c:1152 [inline]
__kfree_skb+0x55/0x70 net/core/skbuff.c:1166
tcp_clean_rtx_queue net/ipv4/tcp_input.c:3471 [inline]
tcp_ack+0x2266/0x6950 net/ipv4/tcp_input.c:4096
tcp_rcv_established+0x93c/0x2670 net/ipv4/tcp_input.c:6430
tcp_v4_do_rcv+0xe1a/0x12b0 net/ipv4/tcp_ipv4.c:1931
sk_backlog_rcv include/net/sock.h:1158 [inline]
__release_sock+0x285/0x3e0 net/core/sock.c:3180
__sk_flush_backlog+0x4b/0xe0 net/core/sock.c:3203
sk_flush_backlog include/net/sock.h:1221 [inline]
tcp_sendmsg_locked+0x4309/0x5550 net/ipv4/tcp.c:1214
tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1413
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg+0x19c/0x270 net/socket.c:742
sock_write_iter+0x27f/0x370 net/socket.c:1195
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5d5/0xb40 fs/read_write.c:686
ksys_write+0x14b/0x260 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
Memory state around the buggy address:
ffff8880338ae080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880338ae100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880338ae180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880338ae200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880338ae280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
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If the report is already addressed, let syzbot know by replying with:
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If you want to overwrite report's subsystems, reply with:
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(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
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syzbot found the following issue on:
HEAD commit: 211ddde0823f Linux 6.18-rc2
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16304e7c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=216353986aa62c5d
dashboard link: https://syzkaller.appspot.com/bug?extid=addf1973f8732e2cc468
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/07371cf02d4e/disk-211ddde0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/27220c94ca08/vmlinux-211ddde0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/12abd01b8291/bzImage-211ddde0.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+addf19...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
Read of size 1 at addr ffff8880338ae1c0 by task syz.7.3131/20318
CPU: 0 UID: 0 PID: 20318 Comm: syz.7.3131 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
__kasan_check_byte+0x2a/0x40 mm/kasan/common.c:580
kasan_check_byte include/linux/kasan.h:401 [inline]
lock_acquire+0x8d/0x360 kernel/locking/lockdep.c:5842
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
rtlock_slowlock kernel/locking/rtmutex.c:1894 [inline]
rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
__rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
rt_spin_lock+0x14a/0x3e0 kernel/locking/spinlock_rt.c:57
spin_lock include/linux/spinlock_rt.h:44 [inline]
__wake_up_common_lock+0x2f/0x1e0 kernel/sched/wait.c:124
snd_pcm_action_single sound/core/pcm_native.c:-1 [inline]
snd_pcm_action+0x1f4/0x240 sound/core/pcm_native.c:1393
loopback_check_format sound/drivers/aloop.c:363 [inline]
loopback_trigger+0xb82/0x1b60 sound/drivers/aloop.c:411
snd_pcm_do_start+0xb7/0x180 sound/core/pcm_native.c:1454
snd_pcm_action_single sound/core/pcm_native.c:1310 [inline]
snd_pcm_action+0xe7/0x240 sound/core/pcm_native.c:1393
__snd_pcm_lib_xfer+0x1762/0x1ce0 sound/core/pcm_lib.c:2405
snd_pcm_oss_write3+0x1bc/0x320 sound/core/oss/pcm_oss.c:1241
snd_pcm_plug_write_transfer+0x2cb/0x4c0 sound/core/oss/pcm_plugin.c:630
snd_pcm_oss_write2 sound/core/oss/pcm_oss.c:1373 [inline]
snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1439 [inline]
snd_pcm_oss_write+0xba2/0x11a0 sound/core/oss/pcm_oss.c:2794
vfs_write+0x287/0xb40 fs/read_write.c:684
ksys_write+0x14b/0x260 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd64e82efc9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd64ca75038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd64ea86090 RCX: 00007fd64e82efc9
RDX: 0000000000004000 RSI: 00002000000012c0 RDI: 0000000000000005
RBP: 00007fd64e8b1f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd64ea86128 R14: 00007fd64ea86090 R15: 00007ffd87fbae38
</TASK>
Allocated by task 20315:
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417
kasan_kmalloc include/linux/kasan.h:262 [inline]
__kmalloc_cache_noprof+0x1ef/0x6c0 mm/slub.c:5755
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
snd_pcm_attach_substream+0x5b7/0xb50 sound/core/pcm.c:938
snd_pcm_open_substream+0xb9/0x23a0 sound/core/pcm_native.c:2756
snd_pcm_oss_open_file sound/core/oss/pcm_oss.c:2437 [inline]
snd_pcm_oss_open+0xf35/0x1bf0 sound/core/oss/pcm_oss.c:2518
chrdev_open+0x4cf/0x5e0 fs/char_dev.c:414
do_dentry_open+0x9b1/0x1350 fs/open.c:965
vfs_open+0x3b/0x350 fs/open.c:1097
do_open fs/namei.c:3975 [inline]
path_openat+0x2ef1/0x3840 fs/namei.c:4134
do_filp_open+0x1fa/0x410 fs/namei.c:4161
do_sys_openat2+0x121/0x1c0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 20314:
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
__kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587
kasan_save_free_info mm/kasan/kasan.h:406 [inline]
poison_slab_object mm/kasan/common.c:252 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2530 [inline]
slab_free mm/slub.c:6619 [inline]
kfree+0x197/0x950 mm/slub.c:6826
snd_pcm_detach_substream+0x1e1/0x290 sound/core/pcm.c:1003
snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2396 [inline]
snd_pcm_oss_release+0x184/0x250 sound/core/oss/pcm_oss.c:2575
__fput+0x45b/0xa80 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff8880338ae000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 448 bytes inside of
freed 2048-byte region [ffff8880338ae000, ffff8880338ae800)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x338a8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea0000ce2a01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5810, tgid 5810 (syz-executor), ts 87951115432, free_ts 83939004793
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850
prep_new_page mm/page_alloc.c:1858 [inline]
get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3884
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
alloc_slab_page mm/slub.c:3046 [inline]
allocate_slab+0x96/0x3a0 mm/slub.c:3219
new_slab mm/slub.c:3273 [inline]
___slab_alloc+0xb12/0x13f0 mm/slub.c:4643
__slab_alloc+0xc6/0x1f0 mm/slub.c:4762
__slab_alloc_node mm/slub.c:4838 [inline]
slab_alloc_node mm/slub.c:5260 [inline]
__do_kmalloc_node mm/slub.c:5633 [inline]
__kmalloc_node_track_caller_noprof+0x2a8/0x7e0 mm/slub.c:5743
kmalloc_reserve+0x136/0x290 net/core/skbuff.c:601
__alloc_skb+0x142/0x2d0 net/core/skbuff.c:670
alloc_skb include/linux/skbuff.h:1383 [inline]
nlmsg_new include/net/netlink.h:1055 [inline]
rtmsg_ifinfo_build_skb+0x84/0x260 net/core/rtnetlink.c:4400
rtmsg_ifinfo_event net/core/rtnetlink.c:4442 [inline]
rtmsg_ifinfo+0x8c/0x1a0 net/core/rtnetlink.c:4451
register_netdevice+0x1746/0x1b10 net/core/dev.c:11346
__ip_tunnel_create+0x3e7/0x560 net/ipv4/ip_tunnel.c:268
ip_tunnel_init_net+0x2ba/0x800 net/ipv4/ip_tunnel.c:1147
ops_init+0x35c/0x5c0 net/core/net_namespace.c:137
page last free pid 5784 tgid 5784 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
__free_frozen_pages+0xfb6/0x1140 mm/page_alloc.c:2906
__folio_put+0x247/0x300 mm/swap.c:112
put_netmem net/core/skbuff.c:7376 [inline]
skb_page_unref include/linux/skbuff_ref.h:43 [inline]
__skb_frag_unref include/linux/skbuff_ref.h:56 [inline]
skb_release_data+0x49a/0x7c0 net/core/skbuff.c:1081
skb_release_all net/core/skbuff.c:1152 [inline]
__kfree_skb+0x55/0x70 net/core/skbuff.c:1166
tcp_clean_rtx_queue net/ipv4/tcp_input.c:3471 [inline]
tcp_ack+0x2266/0x6950 net/ipv4/tcp_input.c:4096
tcp_rcv_established+0x93c/0x2670 net/ipv4/tcp_input.c:6430
tcp_v4_do_rcv+0xe1a/0x12b0 net/ipv4/tcp_ipv4.c:1931
sk_backlog_rcv include/net/sock.h:1158 [inline]
__release_sock+0x285/0x3e0 net/core/sock.c:3180
__sk_flush_backlog+0x4b/0xe0 net/core/sock.c:3203
sk_flush_backlog include/net/sock.h:1221 [inline]
tcp_sendmsg_locked+0x4309/0x5550 net/ipv4/tcp.c:1214
tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1413
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg+0x19c/0x270 net/socket.c:742
sock_write_iter+0x27f/0x370 net/socket.c:1195
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5d5/0xb40 fs/read_write.c:686
ksys_write+0x14b/0x260 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
Memory state around the buggy address:
ffff8880338ae080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880338ae100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880338ae180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880338ae200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880338ae280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot
Dec 21, 2025, 7:11:23 PM12/21/25
to linux-...@vger.kernel.org, linux...@vger.kernel.org, pe...@perex.cz, syzkall...@googlegroups.com, ti...@suse.com
syzbot has found a reproducer for the following issue on:
HEAD commit: 9094662f6707 Merge tag 'ata-6.19-rc2' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1568ddb4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1f2b6fe1fdf1a00b
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1762db1a580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/024031cc0ef1/disk-9094662f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ba00f3b9b8e7/vmlinux-9094662f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a92db982c114/bzImage-9094662f.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+addf19...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in rt_spin_lock+0x88/0x3e0 kernel/locking/spinlock_rt.c:56
Read of size 1 at addr ffff888034ea7200 by task syz.1.1236/9742
CPU: 1 UID: 0 PID: 9742 Comm: syz.1.1236 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
kasan_check_byte include/linux/kasan.h:401 [inline]
lock_acquire+0x84/0x340 kernel/locking/lockdep.c:5842
rt_spin_lock+0x88/0x3e0 kernel/locking/spinlock_rt.c:56
snd_pcm_oss_write3+0x1bc/0x350 sound/core/oss/pcm_oss.c:1241
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1277acf749
RAX: ffffffffffffffda RBX: 00007f1277d26090 RCX: 00007f1277acf749
RDX: 0000000000004000 RSI: 00002000000012c0 RDI: 0000000000000008
RBP: 00007f1277b53f91 R08: 0000000000000000 R09: 0000000000000000
</TASK>
Allocated by task 9740:
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414
kasan_kmalloc include/linux/kasan.h:262 [inline]
__kmalloc_cache_noprof+0x1fb/0x6d0 mm/slub.c:5776
snd_pcm_open_substream+0xb6/0x2410 sound/core/pcm_native.c:2756
snd_pcm_oss_open_file sound/core/oss/pcm_oss.c:2437 [inline]
snd_pcm_oss_open+0xf2a/0x1bd0 sound/core/oss/pcm_oss.c:2518
chrdev_open+0x4cf/0x5e0 fs/char_dev.c:414
do_dentry_open+0x7d0/0x1270 fs/open.c:962
vfs_open+0x3b/0x350 fs/open.c:1094
do_open fs/namei.c:4628 [inline]
path_openat+0x342a/0x3df0 fs/namei.c:4787
do_filp_open+0x1fa/0x410 fs/namei.c:4814
do_sys_openat2+0x121/0x200 fs/open.c:1430
do_sys_open fs/open.c:1436 [inline]
__do_sys_openat fs/open.c:1452 [inline]
__se_sys_openat fs/open.c:1447 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1447
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 9740:
slab_free mm/slub.c:6670 [inline]
kfree+0x1bd/0x900 mm/slub.c:6878
get_signal+0x11c4/0x1310 kernel/signal.c:2807
arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff888034ea7000
freed 2048-byte region [ffff888034ea7000, ffff888034ea7800)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34ea0
head: 0080000000000003 ffffea0000d3a801 00000000ffffffff 00000000ffffffff
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846
prep_new_page mm/page_alloc.c:1854 [inline]
get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3915
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486
alloc_slab_page mm/slub.c:3075 [inline]
allocate_slab+0x86/0x3b0 mm/slub.c:3248
new_slab mm/slub.c:3302 [inline]
___slab_alloc+0xb10/0x13e0 mm/slub.c:4656
__slab_alloc+0xc6/0x1f0 mm/slub.c:4779
__slab_alloc_node mm/slub.c:4855 [inline]
slab_alloc_node mm/slub.c:5251 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_node_track_caller_noprof+0x2bf/0x810 mm/slub.c:5764
kmalloc_reserve+0x136/0x290 net/core/skbuff.c:608
pskb_expand_head+0x19d/0x1160 net/core/skbuff.c:2282
netlink_trim+0x1b3/0x2c0 net/netlink/af_netlink.c:1299
netlink_broadcast_filtered+0xd6/0x1000 net/netlink/af_netlink.c:1512
nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
nlmsg_multicast include/net/netlink.h:1184 [inline]
nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2593
rtnl_notify net/core/rtnetlink.c:958 [inline]
rtmsg_ifinfo_send net/core/rtnetlink.c:4436 [inline]
rtmsg_ifinfo_event net/core/rtnetlink.c:4452 [inline]
rtnetlink_event+0x224/0x270 net/core/rtnetlink.c:7018
notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
call_netdevice_notifiers net/core/dev.c:2282 [inline]
netif_change_name+0x5db/0x970 net/core/dev.c:1490
page last free pid 5966 tgid 5966 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1395 [inline]
__free_frozen_pages+0xfe1/0x1170 mm/page_alloc.c:2943
discard_slab mm/slub.c:3346 [inline]
__put_partials+0x149/0x170 mm/slub.c:3886
__slab_free+0x2af/0x330 mm/slub.c:5952
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:349
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x18d/0x6c0 mm/slub.c:5270
getname_flags+0xb8/0x540 fs/namei.c:146
user_path_at+0x24/0x60 fs/namei.c:3566
user_statfs+0x94/0x170 fs/statfs.c:103
__do_sys_statfs fs/statfs.c:193 [inline]
__se_sys_statfs fs/statfs.c:190 [inline]
__x64_sys_statfs+0xe0/0x1b0 fs/statfs.c:190
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff888034ea7100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888034ea7180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888034ea7200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888034ea7280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888034ea7300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
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.
HEAD commit: 9094662f6707 Merge tag 'ata-6.19-rc2' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1568ddb4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1f2b6fe1fdf1a00b
dashboard link: https://syzkaller.appspot.com/bug?extid=addf1973f8732e2cc468
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13b343c2580000
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1762db1a580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/024031cc0ef1/disk-9094662f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ba00f3b9b8e7/vmlinux-9094662f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a92db982c114/bzImage-9094662f.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+addf19...@syzkaller.appspotmail.com
==================================================================
Read of size 1 at addr ffff888034ea7200 by task syz.1.1236/9742
CPU: 1 UID: 0 PID: 9742 Comm: syz.1.1236 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
__kasan_check_byte+0x2a/0x40 mm/kasan/common.c:573
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
kasan_check_byte include/linux/kasan.h:401 [inline]
lock_acquire+0x84/0x340 kernel/locking/lockdep.c:5842
rt_spin_lock+0x88/0x3e0 kernel/locking/spinlock_rt.c:56
spin_lock include/linux/spinlock_rt.h:44 [inline]
__wake_up_common_lock+0x2f/0x1e0 kernel/sched/wait.c:124
snd_pcm_action_single sound/core/pcm_native.c:-1 [inline]
snd_pcm_action+0x1f4/0x240 sound/core/pcm_native.c:1393
loopback_check_format sound/drivers/aloop.c:363 [inline]
loopback_trigger+0xb82/0x1b60 sound/drivers/aloop.c:411
snd_pcm_do_start+0xb7/0x180 sound/core/pcm_native.c:1454
snd_pcm_action_single sound/core/pcm_native.c:1310 [inline]
snd_pcm_action+0xe7/0x240 sound/core/pcm_native.c:1393
__snd_pcm_lib_xfer+0x1762/0x1d00 sound/core/pcm_lib.c:2405
__wake_up_common_lock+0x2f/0x1e0 kernel/sched/wait.c:124
snd_pcm_action_single sound/core/pcm_native.c:-1 [inline]
snd_pcm_action+0x1f4/0x240 sound/core/pcm_native.c:1393
loopback_check_format sound/drivers/aloop.c:363 [inline]
loopback_trigger+0xb82/0x1b60 sound/drivers/aloop.c:411
snd_pcm_do_start+0xb7/0x180 sound/core/pcm_native.c:1454
snd_pcm_action_single sound/core/pcm_native.c:1310 [inline]
snd_pcm_action+0xe7/0x240 sound/core/pcm_native.c:1393
snd_pcm_oss_write3+0x1bc/0x350 sound/core/oss/pcm_oss.c:1241
snd_pcm_plug_write_transfer+0x2cb/0x4c0 sound/core/oss/pcm_plugin.c:630
snd_pcm_oss_write2 sound/core/oss/pcm_oss.c:1373 [inline]
snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1439 [inline]
snd_pcm_oss_write+0xa31/0xf20 sound/core/oss/pcm_oss.c:2794
snd_pcm_oss_write2 sound/core/oss/pcm_oss.c:1373 [inline]
snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1439 [inline]
vfs_write+0x287/0xb40 fs/read_write.c:684
ksys_write+0x14b/0x260 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
ksys_write+0x14b/0x260 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1277acf749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1277115038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f1277d26090 RCX: 00007f1277acf749
RDX: 0000000000004000 RSI: 00002000000012c0 RDI: 0000000000000008
RBP: 00007f1277b53f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1277d26128 R14: 00007f1277d26090 R15: 00007ffea9722d18
</TASK>
Allocated by task 9740:
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414
kasan_kmalloc include/linux/kasan.h:262 [inline]
__kmalloc_cache_noprof+0x1fb/0x6d0 mm/slub.c:5776
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
snd_pcm_attach_substream+0x5b7/0xb30 sound/core/pcm.c:938
kzalloc_noprof include/linux/slab.h:1094 [inline]
snd_pcm_open_substream+0xb6/0x2410 sound/core/pcm_native.c:2756
snd_pcm_oss_open_file sound/core/oss/pcm_oss.c:2437 [inline]
snd_pcm_oss_open+0xf2a/0x1bd0 sound/core/oss/pcm_oss.c:2518
chrdev_open+0x4cf/0x5e0 fs/char_dev.c:414
do_dentry_open+0x7d0/0x1270 fs/open.c:962
vfs_open+0x3b/0x350 fs/open.c:1094
do_open fs/namei.c:4628 [inline]
path_openat+0x342a/0x3df0 fs/namei.c:4787
do_filp_open+0x1fa/0x410 fs/namei.c:4814
do_sys_openat2+0x121/0x200 fs/open.c:1430
do_sys_open fs/open.c:1436 [inline]
__do_sys_openat fs/open.c:1452 [inline]
__se_sys_openat fs/open.c:1447 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1447
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 9740:
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
poison_slab_object mm/kasan/common.c:252 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2540 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free mm/slub.c:6670 [inline]
kfree+0x1bd/0x900 mm/slub.c:6878
snd_pcm_detach_substream+0x1e1/0x290 sound/core/pcm.c:1003
snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2396 [inline]
snd_pcm_oss_release+0x184/0x250 sound/core/oss/pcm_oss.c:2575
__fput+0x45b/0xa80 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:233
snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2396 [inline]
snd_pcm_oss_release+0x184/0x250 sound/core/oss/pcm_oss.c:2575
__fput+0x45b/0xa80 fs/file_table.c:468
get_signal+0x11c4/0x1310 kernel/signal.c:2807
arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff888034ea7000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 512 bytes inside of
freed 2048-byte region [ffff888034ea7000, ffff888034ea7800)
The buggy address belongs to the physical page:
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122
head: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122
head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea0000d3a801 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5917, tgid 5917 (syz-executor), ts 127811454833, free_ts 125843464373
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846
prep_new_page mm/page_alloc.c:1854 [inline]
get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3915
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486
alloc_slab_page mm/slub.c:3075 [inline]
allocate_slab+0x86/0x3b0 mm/slub.c:3248
new_slab mm/slub.c:3302 [inline]
___slab_alloc+0xb10/0x13e0 mm/slub.c:4656
__slab_alloc+0xc6/0x1f0 mm/slub.c:4779
__slab_alloc_node mm/slub.c:4855 [inline]
slab_alloc_node mm/slub.c:5251 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_node_track_caller_noprof+0x2bf/0x810 mm/slub.c:5764
kmalloc_reserve+0x136/0x290 net/core/skbuff.c:608
pskb_expand_head+0x19d/0x1160 net/core/skbuff.c:2282
netlink_trim+0x1b3/0x2c0 net/netlink/af_netlink.c:1299
netlink_broadcast_filtered+0xd6/0x1000 net/netlink/af_netlink.c:1512
nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
nlmsg_multicast include/net/netlink.h:1184 [inline]
nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2593
rtnl_notify net/core/rtnetlink.c:958 [inline]
rtmsg_ifinfo_send net/core/rtnetlink.c:4436 [inline]
rtmsg_ifinfo_event net/core/rtnetlink.c:4452 [inline]
rtnetlink_event+0x224/0x270 net/core/rtnetlink.c:7018
notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
call_netdevice_notifiers net/core/dev.c:2282 [inline]
netif_change_name+0x5db/0x970 net/core/dev.c:1490
page last free pid 5966 tgid 5966 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1395 [inline]
__free_frozen_pages+0xfe1/0x1170 mm/page_alloc.c:2943
discard_slab mm/slub.c:3346 [inline]
__put_partials+0x149/0x170 mm/slub.c:3886
__slab_free+0x2af/0x330 mm/slub.c:5952
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:349
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x18d/0x6c0 mm/slub.c:5270
getname_flags+0xb8/0x540 fs/namei.c:146
user_path_at+0x24/0x60 fs/namei.c:3566
user_statfs+0x94/0x170 fs/statfs.c:103
__do_sys_statfs fs/statfs.c:193 [inline]
__se_sys_statfs fs/statfs.c:190 [inline]
__x64_sys_statfs+0xe0/0x1b0 fs/statfs.c:190
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff888034ea7180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888034ea7200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888034ea7280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888034ea7300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
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.
Hillf Danton
Dec 21, 2025, 9:29:17 PM12/21/25
to syzbot, linux-...@vger.kernel.org, linux...@vger.kernel.org, pe...@perex.cz, syzkall...@googlegroups.com, ti...@suse.com
Date: Sun, 21 Dec 2025 16:11:22 -0800
What is weird is why snd_pcm_oss_write failed to block snd_pcm_oss_release
in file_operations POV. By weird I mean file can not be closed with a writer.
in file_operations POV. By weird I mean file can not be closed with a writer.
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