syzbot

==================================================================
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+0x40/0x60 kernel/locking/spinlock.c:162
Read of size 1 at addr ffff888024d24440 by task syz-executor/18767

CPU: 0 UID: 0 PID: 18767 Comm: syz-executor Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
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:574
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire+0x84/0x340 kernel/locking/lockdep.c:5842
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
 rt_mutex_slowunlock+0xb0/0x8a0 kernel/locking/rtmutex.c:1417
 shrink_dentry_list+0x2e3/0x5e0 fs/dcache.c:1164
 shrink_dcache_tree+0xca/0x2e0 fs/dcache.c:-1
 shrink_dcache_parent fs/dcache.c:1616 [inline]
 d_invalidate+0x11d/0x260 fs/dcache.c:1698
 proc_invalidate_siblings_dcache+0x3d3/0x6c0 fs/proc/inode.c:142
 release_task+0x11d4/0x16d0 kernel/exit.c:291
 wait_task_zombie kernel/exit.c:1274 [inline]
 wait_consider_task+0x1944/0x2e10 kernel/exit.c:1501
 do_wait_thread kernel/exit.c:1564 [inline]
 __do_wait+0x156/0x740 kernel/exit.c:1682
 do_wait+0x1e8/0x4f0 kernel/exit.c:1716
 kernel_wait4+0x1af/0x280 kernel/exit.c:1875
 __do_sys_wait4 kernel/exit.c:1903 [inline]
 __se_sys_wait4 kernel/exit.c:1899 [inline]
 __x64_sys_wait4+0x133/0x1e0 kernel/exit.c:1899
 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: 0033:0x7f468ebc5897
Code: 89 7c 24 10 48 89 4c 24 18 e8 65 1c 03 00 4c 8b 54 24 18 8b 54 24 14 41 89 c0 48 8b 74 24 08 8b 7c 24 10 b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 89 44 24 10 e8 b5 1c 03 00 8b 44
RSP: 002b:00007ffc51d7d4b0 EFLAGS: 00000293 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 0000000000000117 RCX: 00007f468ebc5897
RDX: 0000000040000001 RSI: 00007ffc51d7d51c RDI: 00000000ffffffff
RBP: 00007ffc51d7d51c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000001388
R13: 00000000000927c0 R14: 00000000001b9f59 R15: 00007ffc51d7d570
 </TASK>

Allocated by task 20761:
 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:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_lru_noprof+0x193/0x6c0 mm/slub.c:5282
 __d_alloc+0x37/0x6f0 fs/dcache.c:1730
 d_alloc_parallel+0xe1/0x1610 fs/dcache.c:2594
 __lookup_slow+0x11c/0x3d0 fs/namei.c:1843
 lookup_slow+0x53/0x70 fs/namei.c:1875
 walk_component fs/namei.c:2221 [inline]
 link_path_walk+0x1273/0x18d0 fs/namei.c:2586
 path_openat+0x2bf/0x3df0 fs/namei.c:4783
 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 20:
 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:2540 [inline]
 slab_free mm/slub.c:6670 [inline]
 kmem_cache_free+0x18f/0x8d0 mm/slub.c:6781
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core kernel/rcu/tree.c:2857 [inline]
 rcu_cpu_kthread+0xba5/0x1af0 kernel/rcu/tree.c:2945
 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

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:3119 [inline]
 call_rcu+0xee/0x890 kernel/rcu/tree.c:3239
 __dentry_kill+0x4d2/0x660 fs/dcache.c:689
 finish_dput+0xc9/0x480 fs/dcache.c:879
 proc_invalidate_siblings_dcache+0x3db/0x6c0 fs/proc/inode.c:143
 release_task+0x11d4/0x16d0 kernel/exit.c:291
 exit_notify kernel/exit.c:777 [inline]
 do_exit+0x15e6/0x22f0 kernel/exit.c:983
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
 get_signal+0x125d/0x1310 kernel/signal.c:3034
 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+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888024d24370
 which belongs to the cache dentry of size 376
The buggy address is located 208 bytes inside of
 freed 376-byte region [ffff888024d24370, ffff888024d244e8)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24d24
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff8880623d7001
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff8881404098c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000120012 00000000f5000000 ffff8880623d7001
head: 0080000000000040 ffff8881404098c0 dead000000000100 dead000000000122
head: 0000000000000000 0000000000120012 00000000f5000000 ffff8880623d7001
head: 0080000000000001 ffffea0000934901 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 1553, tgid 1553 (kworker/u8:1), ts 15253870752, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857
 prep_new_page mm/page_alloc.c:1865 [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]
 kmem_cache_alloc_lru_noprof+0x104/0x6c0 mm/slub.c:5282
 __d_alloc+0x37/0x6f0 fs/dcache.c:1730
 d_alloc_parallel+0xe1/0x1610 fs/dcache.c:2594
 __lookup_slow+0x11c/0x3d0 fs/namei.c:1843
 lookup_slow+0x53/0x70 fs/namei.c:1875
 walk_component fs/namei.c:2221 [inline]
 link_path_walk+0xd1e/0x18d0 fs/namei.c:2589
 path_openat+0x2bf/0x3df0 fs/namei.c:4783
 do_filp_open+0x1fa/0x410 fs/namei.c:4814
 do_open_execat+0x135/0x560 fs/exec.c:783
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888024d24300: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fa fb
 ffff888024d24380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888024d24400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888024d24480: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
 ffff888024d24500: fc fc fc fc fc 00 00 00 00 00 00 00 00 00 00 00
==================================================================