syzbot

RBP: 00007ffa7a64e090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffa7c676038 R14: 00007ffa7c675fa0 R15: 00007fffbfcf3ac8
 </TASK>
==================================================================
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 ffff88803b198cd8 by task syz.4.99/6225

CPU: 0 UID: 0 PID: 6225 Comm: syz.4.99 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 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/0xa20 kernel/locking/rtmutex.c:1430
 dentry_kill+0x520/0x880 fs/dcache.c:-1
 finish_dput+0x1a/0x260 fs/dcache.c:1001
 proc_invalidate_siblings_dcache+0x3db/0x6c0 fs/proc/inode.c:143
 release_task+0x11c8/0x16c0 kernel/exit.c:291
 exit_notify kernel/exit.c:805 [inline]
 do_exit+0x168c/0x2360 kernel/exit.c:1016
 do_group_exit+0x22d/0x2f0 kernel/exit.c:1147
 get_signal+0x121b/0x12c0 kernel/signal.c:3038
 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0x104/0x730 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffa7c3fce59
Code: Unable to access opcode bytes at 0x7ffa7c3fce2f.
RSP: 002b:00007ffa7a64e0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007ffa7c675fa8 RCX: 00007ffa7c3fce59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ffa7c675fa8
RBP: 00007ffa7c675fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffa7c676038 R14: 00007fffbfcf39e0 R15: 00007fffbfcf3ac8
 </TASK>

Allocated by task 6225:
 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:4612 [inline]
 slab_alloc_node mm/slub.c:4945 [inline]
 kmem_cache_alloc_lru_noprof+0x353/0x650 mm/slub.c:4978
 __d_alloc+0x37/0x6f0 fs/dcache.c:1902
 d_alloc_parallel+0xde/0x16c0 fs/dcache.c:2761
 __lookup_slow+0x82/0x2f0 fs/namei.c:1904
 lookup_slow+0x53/0x70 fs/namei.c:1936
 walk_component fs/namei.c:2282 [inline]
 link_path_walk+0x12a5/0x1910 fs/namei.c:2653
 path_openat+0x23c/0x3850 fs/namei.c:4855
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_sys_openat2+0x115/0x200 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1385
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 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+0x40/0x50 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:2705 [inline]
 slab_free mm/slub.c:6405 [inline]
 kmem_cache_free+0x187/0x6c0 mm/slub.c:6532
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core kernel/rcu/tree.c:2897 [inline]
 rcu_cpu_kthread+0x950/0x1480 kernel/rcu/tree.c:2985
 smpboot_thread_fn+0x57c/0xa80 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:3159 [inline]
 call_rcu+0xee/0x8b0 kernel/rcu/tree.c:3279
 dentry_kill+0x4d3/0x880 fs/dcache.c:845
 shrink_kill fs/dcache.c:1275 [inline]
 shrink_dentry_list+0x20c/0x320 fs/dcache.c:1292
 shrink_dcache_tree+0xe7/0x410 fs/dcache.c:1725
 shrink_dcache_parent fs/dcache.c:1767 [inline]
 d_invalidate+0xde/0x260 fs/dcache.c:1870
 proc_invalidate_siblings_dcache+0x3d3/0x6c0 fs/proc/inode.c:142
 release_task+0x11c8/0x16c0 kernel/exit.c:291
 wait_task_zombie kernel/exit.c:1309 [inline]
 wait_consider_task+0x197d/0x2df0 kernel/exit.c:1536
 do_wait_thread kernel/exit.c:1599 [inline]
 __do_wait+0x14b/0x720 kernel/exit.c:1717
 do_wait+0x1e7/0x510 kernel/exit.c:1751
 kernel_wait4+0x232/0x2b0 kernel/exit.c:1910
 __do_sys_wait4 kernel/exit.c:1938 [inline]
 __se_sys_wait4 kernel/exit.c:1934 [inline]
 __x64_sys_wait4+0x166/0x240 kernel/exit.c:1934
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88803b198c08
 which belongs to the cache dentry of size 376
The buggy address is located 208 bytes inside of
 freed 376-byte region [ffff88803b198c08, ffff88803b198d80)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3b198
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88801f722b01
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88801be87500 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800120012 00000000f5000000 ffff88801f722b01
head: 0080000000000040 ffff88801be87500 dead000000000100 dead000000000122
head: 0000000000000000 0000000800120012 00000000f5000000 ffff88801f722b01
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 4977, tgid 4977 (udevd), ts 38535548478, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0x2639/0x26b0 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3294 [inline]
 allocate_slab+0x79/0x5e0 mm/slub.c:3408
 new_slab mm/slub.c:3454 [inline]
 refill_objects+0x2d8/0x350 mm/slub.c:7338
 refill_sheaf mm/slub.c:2832 [inline]
 __pcs_replace_empty_main+0x330/0x690 mm/slub.c:4703
 alloc_from_pcs mm/slub.c:4801 [inline]
 slab_alloc_node mm/slub.c:4933 [inline]
 kmem_cache_alloc_lru_noprof+0x44b/0x650 mm/slub.c:4978
 __d_alloc+0x37/0x6f0 fs/dcache.c:1902
 d_alloc_parallel+0xde/0x16c0 fs/dcache.c:2761
 __lookup_slow+0x82/0x2f0 fs/namei.c:1904
 lookup_slow+0x53/0x70 fs/namei.c:1936
 walk_component fs/namei.c:2282 [inline]
 link_path_walk+0xd2a/0x1910 fs/namei.c:2656
 path_openat+0x23c/0x3850 fs/namei.c:4855
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_sys_openat2+0x115/0x200 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1385
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88803b198b80: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
 ffff88803b198c00: fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88803b198c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff88803b198d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803b198d80: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
==================================================================