syzbot

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BUG: KASAN: slab-use-after-free in rt_spin_lock+0x88/0x2c0 kernel/locking/spinlock_rt.c:56
Read of size 1 at addr ffff88803d47e200 by task syz.4.2327/13763

CPU: 1 UID: 0 PID: 13763 Comm: syz.4.2327 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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:568
 kasan_check_byte include/linux/kasan.h:399 [inline]
 lock_acquire+0x8d/0x360 kernel/locking/lockdep.c:5842
 rt_spin_lock+0x88/0x2c0 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:1388
 loopback_check_format sound/drivers/aloop.c:363 [inline]
 loopback_trigger+0xb01/0x1ac0 sound/drivers/aloop.c:411
 snd_pcm_do_start+0xb4/0x180 sound/core/pcm_native.c:1449
 snd_pcm_action_single sound/core/pcm_native.c:1305 [inline]
 snd_pcm_action+0xe7/0x240 sound/core/pcm_native.c:1388
 __snd_pcm_lib_xfer+0x1767/0x1ce0 sound/core/pcm_lib.c:2405
 snd_pcm_oss_write3+0x1bc/0x320 sound/core/oss/pcm_oss.c:1241
 snd_pcm_plug_write_transfer+0x2c8/0x4c0 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:2795
 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/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd3fb75eba9
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:00007fd3f9559038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd3fb9a6270 RCX: 00007fd3fb75eba9
RDX: 0000000000004000 RSI: 00002000000012c0 RDI: 0000000000000007
RBP: 00007fd3fb7e1e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd3fb9a6308 R14: 00007fd3fb9a6270 R15: 00007fffebeb77c8
 </TASK>

Allocated by task 13767:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:405
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x1a8/0x320 mm/slub.c:4407
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 snd_pcm_attach_substream+0x5b7/0xb50 sound/core/pcm.c:938
 snd_pcm_open_substream+0xb9/0x23a0 sound/core/pcm_native.c:2751
 snd_pcm_oss_open_file sound/core/oss/pcm_oss.c:2438 [inline]
 snd_pcm_oss_open+0xf35/0x1bf0 sound/core/oss/pcm_oss.c:2519
 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:1095
 do_open fs/namei.c:3887 [inline]
 path_openat+0x2ef1/0x3840 fs/namei.c:4046
 do_filp_open+0x1fa/0x410 fs/namei.c:4073
 do_sys_openat2+0x121/0x1c0 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1461
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 13767:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2422 [inline]
 slab_free mm/slub.c:4695 [inline]
 kfree+0x195/0x550 mm/slub.c:4894
 snd_pcm_detach_substream+0x1e1/0x290 sound/core/pcm.c:1003
 snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2397 [inline]
 snd_pcm_oss_release+0x184/0x250 sound/core/oss/pcm_oss.c:2576
 __fput+0x458/0xa80 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 get_signal+0x11c5/0x1310 kernel/signal.c:2807
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
 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/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88803d47e000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 512 bytes inside of
 freed 2048-byte region [ffff88803d47e000, ffff88803d47e800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d478
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 ffff888019842000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 0080000000000040 ffff888019842000 dead000000000100 dead000000000122
head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea0000f51e01 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5847, tgid 5847 (syz-executor), ts 112599484527, free_ts 112593331798
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x2119/0x21b0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:2492 [inline]
 allocate_slab+0x8a/0x370 mm/slub.c:2660
 new_slab mm/slub.c:2714 [inline]
 ___slab_alloc+0x8d1/0xdc0 mm/slub.c:3901
 __slab_alloc mm/slub.c:3992 [inline]
 __slab_alloc_node mm/slub.c:4067 [inline]
 slab_alloc_node mm/slub.c:4228 [inline]
 __do_kmalloc_node mm/slub.c:4375 [inline]
 __kmalloc_node_track_caller_noprof+0x14c/0x450 mm/slub.c:4395
 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:600
 pskb_expand_head+0x18e/0x1150 net/core/skbuff.c:2240
 netlink_trim+0x1d5/0x2e0 net/netlink/af_netlink.c:1301
 netlink_broadcast_filtered+0xd6/0x12c0 net/netlink/af_netlink.c:1514
 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:2595
 __dev_notify_flags+0xf4/0x2e0 net/core/dev.c:9584
 rtnl_configure_link net/core/rtnetlink.c:3591 [inline]
 rtnl_newlink_create+0x61c/0xb00 net/core/rtnetlink.c:3835
 __rtnl_newlink net/core/rtnetlink.c:3942 [inline]
 rtnl_newlink+0x16d6/0x1c70 net/core/rtnetlink.c:4057
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6946
page last free pid 5847 tgid 5847 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xb59/0xce0 mm/page_alloc.c:2895
 discard_slab mm/slub.c:2758 [inline]
 __put_partials+0x159/0x1a0 mm/slub.c:3223
 __slab_free+0x2b3/0x390 mm/slub.c:4565
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:340
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4191 [inline]
 slab_alloc_node mm/slub.c:4240 [inline]
 __kmalloc_cache_noprof+0x143/0x320 mm/slub.c:4402
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 ref_tracker_alloc+0x13b/0x450 lib/ref_tracker.c:271
 __netdev_tracker_alloc include/linux/netdevice.h:4349 [inline]
 netdev_hold include/linux/netdevice.h:4378 [inline]
 netdev_queue_add_kobject net/core/net-sysfs.c:1992 [inline]
 netdev_queue_update_kobjects+0x1ce/0x6c0 net/core/net-sysfs.c:2054
 register_queue_kobjects net/core/net-sysfs.c:2117 [inline]
 netdev_register_kobject+0x258/0x310 net/core/net-sysfs.c:2360
 register_netdevice+0x12a0/0x1b10 net/core/dev.c:11206
 macsec_newlink+0x6be/0x11b0 drivers/net/macsec.c:4231
 rtnl_newlink_create+0x310/0xb00 net/core/rtnetlink.c:3825
 __rtnl_newlink net/core/rtnetlink.c:3942 [inline]
 rtnl_newlink+0x16d6/0x1c70 net/core/rtnetlink.c:4057
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6946
 netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552

Memory state around the buggy address:
 ffff88803d47e100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803d47e180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88803d47e200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88803d47e280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803d47e300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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