================================================================== BUG: KASAN: slab-use-after-free in rt_spin_lock+0x88/0x3e0 kernel/locking/spinlock_rt.c:56 Read of size 1 at addr ffff88805cced200 by task syz.4.466/7862 CPU: 0 UID: 0 PID: 7862 Comm: syz.4.466 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: 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 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 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 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 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f44881df749 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:00007f4486404038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f4488436180 RCX: 00007f44881df749 RDX: 0000000000004000 RSI: 00002000000012c0 RDI: 0000000000000008 RBP: 00007f4488263f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4488436218 R14: 00007f4488436180 R15: 00007ffde2df5e88 Allocated by task 7860: 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_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 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 7854: 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 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] 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 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 ffff88805cced000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 512 bytes inside of freed 2048-byte region [ffff88805cced000, ffff88805cced800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5cce8 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 head: 0080000000000040 ffff88813ff27000 dead000000000100 dead000000000122 head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 0080000000000003 ffffea0001733a01 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 5806, tgid 5806 (syz-executor), ts 94760042164, free_ts 0 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 __dev_notify_flags+0xf4/0x2e0 net/core/dev.c:9769 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9802 do_setlink+0xc55/0x41c0 net/core/rtnetlink.c:3158 page_owner free stack trace missing Memory state around the buggy address: ffff88805cced100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805cced180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88805cced200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88805cced280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805cced300: fb fb fb 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