================================================================== BUG: KASAN: slab-use-after-free in __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166 Read of size 1 at addr ffff88803fbbc0d0 by task syz.3.708/8806 CPU: 0 UID: 0 PID: 8806 Comm: syz.3.708 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: 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 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:574 kasan_check_byte include/linux/kasan.h:402 [inline] lock_acquire+0x84/0x350 kernel/locking/lockdep.c:5844 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166 rt_mutex_slowunlock+0xbf/0x8b0 kernel/locking/rtmutex.c:1426 shrink_dentry_list+0x2e3/0x5e0 fs/dcache.c:1222 prune_dcache_sb+0x119/0x180 fs/dcache.c:1304 super_cache_scan+0x369/0x4b0 fs/super.c:223 do_shrink_slab+0x6fb/0x1150 mm/shrinker.c:436 shrink_slab_memcg mm/shrinker.c:553 [inline] shrink_slab+0x835/0x11f0 mm/shrinker.c:631 drop_slab_node mm/vmscan.c:413 [inline] drop_slab+0x14a/0x290 mm/vmscan.c:431 drop_caches_sysctl_handler+0xc7/0x170 fs/drop_caches.c:68 proc_sys_call_handler+0x4c9/0x830 fs/proc/proc_sysctl.c:600 do_iter_readv_writev+0x62b/0x8d0 fs/read_write.c:-1 vfs_writev+0x345/0x9a0 fs/read_write.c:1059 do_writev+0x15a/0x2e0 fs/read_write.c:1105 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff66538cdd9 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:00007ff663179028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007ff665606270 RCX: 00007ff66538cdd9 RDX: 0000000000000001 RSI: 00002000000000c0 RDI: 0000000000000006 RBP: 00007ff665422d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff665606308 R14: 00007ff665606270 R15: 00007ffcd896a468 Allocated by task 8797: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4577 [inline] slab_alloc_node mm/slub.c:4906 [inline] kmem_cache_alloc_lru_noprof+0x33c/0x680 mm/slub.c:4925 __d_alloc+0x37/0x6f0 fs/dcache.c:1807 d_alloc_parallel+0xe6/0x1610 fs/dcache.c:2671 __lookup_slow+0x152/0x440 fs/namei.c:1900 lookup_slow+0x53/0x70 fs/namei.c:1932 walk_component fs/namei.c:2278 [inline] link_path_walk+0x1273/0x18d0 fs/namei.c:2649 path_openat+0x2d5/0x38a0 fs/namei.c:4854 do_file_open+0x23e/0x4a0 fs/namei.c:4887 do_sys_openat2+0x113/0x200 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1381 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 29: 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:2700 [inline] slab_free mm/slub.c:6258 [inline] kmem_cache_free+0x187/0x6c0 mm/slub.c:6385 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core kernel/rcu/tree.c:2869 [inline] rcu_cpu_kthread+0x99e/0x1470 kernel/rcu/tree.c:2957 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 __call_rcu_common kernel/rcu/tree.c:3131 [inline] call_rcu+0xee/0x890 kernel/rcu/tree.c:3251 __dentry_kill+0x4a9/0x690 fs/dcache.c:737 finish_dput+0xc9/0x480 fs/dcache.c:927 proc_invalidate_siblings_dcache+0x3db/0x6c0 fs/proc/inode.c:143 release_task+0x1207/0x16f0 kernel/exit.c:291 wait_task_zombie kernel/exit.c:1279 [inline] wait_consider_task+0x1966/0x2e30 kernel/exit.c:1506 do_wait_thread kernel/exit.c:1569 [inline] __do_wait+0x155/0x740 kernel/exit.c:1687 do_wait+0x1e7/0x510 kernel/exit.c:1721 kernel_wait4+0x232/0x2b0 kernel/exit.c:1880 __do_sys_wait4 kernel/exit.c:1908 [inline] __se_sys_wait4 kernel/exit.c:1904 [inline] __x64_sys_wait4+0x166/0x240 kernel/exit.c:1904 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88803fbbc000 which belongs to the cache dentry of size 376 The buggy address is located 208 bytes inside of freed 376-byte region [ffff88803fbbc000, ffff88803fbbc178) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3fbbc head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff888031715101 flags: 0x80000000000040(head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000040 ffff88801baf7640 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800120012 00000000f5000000 ffff888031715101 head: 0080000000000040 ffff88801baf7640 dead000000000100 dead000000000122 head: 0000000000000000 0000000800120012 00000000f5000000 ffff888031715101 head: 0080000000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Reclaimable, gfp_mask 0xd20d0(__GFP_RECLAIMABLE|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5612, tgid 5612 (syz-executor), ts 87226097369, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1853 prep_new_page mm/page_alloc.c:1861 [inline] get_page_from_freelist+0x27d6/0x2850 mm/page_alloc.c:3941 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5249 alloc_slab_page mm/slub.c:3289 [inline] allocate_slab+0x74/0x5e0 mm/slub.c:3404 new_slab mm/slub.c:3447 [inline] refill_objects+0x33c/0x3d0 mm/slub.c:7263 refill_sheaf mm/slub.c:2827 [inline] __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4659 alloc_from_pcs mm/slub.c:4757 [inline] slab_alloc_node mm/slub.c:4891 [inline] kmem_cache_alloc_lru_noprof+0x433/0x680 mm/slub.c:4925 __d_alloc+0x37/0x6f0 fs/dcache.c:1807 d_alloc+0x4b/0x190 fs/dcache.c:1886 lookup_one_qstr_excl+0xd8/0x360 fs/namei.c:1801 __start_dirop fs/namei.c:2916 [inline] start_dirop+0x5c/0x90 fs/namei.c:2938 simple_start_creating+0xcc/0x110 fs/libfs.c:2305 debugfs_start_creating+0xdb/0x1a0 fs/debugfs/inode.c:394 __debugfs_create_file+0x6f/0x400 fs/debugfs/inode.c:428 debugfs_create_file_unsafe+0x3a/0x50 fs/debugfs/inode.c:509 nsim_fib_debugfs_init drivers/net/netdevsim/fib.c:1542 [inline] nsim_fib_create+0x2ce/0x9f0 drivers/net/netdevsim/fib.c:1565 page_owner free stack trace missing Memory state around the buggy address: ffff88803fbbbf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88803fbbc000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88803fbbc080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803fbbc100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc ffff88803fbbc180: fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb ==================================================================