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BUG: KASAN: slab-use-after-free in rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56
Read of size 1 at addr ffff888060ee1200 by task syz.2.943/8712

CPU: 0 UID: 0 PID: 8712 Comm: syz.2.943 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:574
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire+0x79/0x2e0 kernel/locking/lockdep.c:5842
 rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56
 spin_lock include/linux/spinlock_rt.h:45 [inline]
 __wake_up_common_lock+0x2f/0x1e0 kernel/sched/wait.c:124
 snd_pcm_post_stop sound/core/pcm_native.c:1551 [inline]
 snd_pcm_action_single sound/core/pcm_native.c:-1 [inline]
 snd_pcm_action sound/core/pcm_native.c:1398 [inline]
 snd_pcm_stop+0x428/0x550 sound/core/pcm_native.c:1571
 loopback_check_format sound/drivers/aloop.c:400 [inline]
 loopback_trigger+0x1240/0x1d50 sound/drivers/aloop.c:421
 snd_pcm_do_start sound/core/pcm_native.c:1459 [inline]
 snd_pcm_action_single sound/core/pcm_native.c:1315 [inline]
 snd_pcm_action sound/core/pcm_native.c:1398 [inline]
 snd_pcm_start+0x43d/0x5d0 sound/core/pcm_native.c:1506
 __snd_pcm_lib_xfer+0x175a/0x1d10 sound/core/pcm_lib.c:2405
 snd_pcm_oss_write3+0x1bc/0x350 sound/core/oss/pcm_oss.c:1245
 snd_pcm_oss_write2+0x2c2/0x440 sound/core/oss/pcm_oss.c:1385
 snd_pcm_oss_sync1+0x194/0x540 sound/core/oss/pcm_oss.c:1619
 snd_pcm_oss_sync+0xab2/0xfc0 sound/core/oss/pcm_oss.c:1684
 snd_pcm_oss_release+0x102/0x250 sound/core/oss/pcm_oss.c:2578
 __fput+0x461/0xa90 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __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 include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f13ad45c819
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:00007ffcce5489b8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f13ad6d7da0 RCX: 00007f13ad45c819
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f13ad6d7da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00007f13ad6d7cb0 R11: 0000000000000246 R12: 0000000000048b3e
R13: 00007f13ad6d609c R14: 0000000000048895 R15: 00007f13ad6d6090
 </TASK>

Allocated by task 8714:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3a6/0x690 mm/slub.c:5380
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 snd_pcm_attach_substream+0x5b7/0xb20 sound/core/pcm.c:938
 snd_pcm_open_substream+0xbd/0x2420 sound/core/pcm_native.c:2774
 snd_pcm_oss_open_file sound/core/oss/pcm_oss.c:2442 [inline]
 snd_pcm_oss_open+0xfc2/0x1c50 sound/core/oss/pcm_oss.c:2523
 chrdev_open+0x4d0/0x5f0 fs/char_dev.c:411
 do_dentry_open+0x83d/0x13e0 fs/open.c:949
 vfs_open+0x3b/0x350 fs/open.c:1081
 do_open fs/namei.c:4677 [inline]
 path_openat+0x2e43/0x38a0 fs/namei.c:4836
 do_file_open+0x23e/0x4a0 fs/namei.c:4865
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 8714:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2685 [inline]
 slab_free mm/slub.c:6165 [inline]
 kfree+0x1c1/0x6c0 mm/slub.c:6483
 snd_pcm_detach_substream+0x1e1/0x290 sound/core/pcm.c:1003
 snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2401 [inline]
 snd_pcm_oss_release+0x184/0x250 sound/core/oss/pcm_oss.c:2580
 __fput+0x461/0xa90 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __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 include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888060ee1000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 512 bytes inside of
 freed 2048-byte region [ffff888060ee1000, ffff888060ee1800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888060ee4000 pfn:0x60ee0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000240(workingset|head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000240 ffff88813fe1b000 ffffea00017fe010 ffffea0000c6dc10
raw: ffff888060ee4000 0000000800080006 00000000f5000000 0000000000000000
head: 0080000000000240 ffff88813fe1b000 ffffea00017fe010 ffffea0000c6dc10
head: ffff888060ee4000 0000000800080006 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea000183b801 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 5150, tgid 5150 (klogd), ts 79786515820, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3292 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3481
 new_slab mm/slub.c:3539 [inline]
 refill_objects+0x334/0x3c0 mm/slub.c:7175
 refill_sheaf mm/slub.c:2812 [inline]
 __pcs_replace_empty_main+0x35c/0x710 mm/slub.c:4615
 alloc_from_pcs mm/slub.c:4717 [inline]
 slab_alloc_node mm/slub.c:4851 [inline]
 __kmalloc_cache_noprof+0x44e/0x690 mm/slub.c:5375
 kmalloc_noprof include/linux/slab.h:950 [inline]
 syslog_print+0x103/0x610 kernel/printk/printk.c:1585
 do_syslog+0x583/0x7d0 kernel/printk/printk.c:1763
 __do_sys_syslog kernel/printk/printk.c:1855 [inline]
 __se_sys_syslog kernel/printk/printk.c:1853 [inline]
 __x64_sys_syslog+0x7c/0x90 kernel/printk/printk.c:1853
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888060ee1100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888060ee1180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888060ee1200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888060ee1280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888060ee1300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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