syzbot

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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 ffff888023386440 by task kworker/u8:2/1528

CPU: 0 UID: 0 PID: 1528 Comm: kworker/u8:2 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/0x8b0 kernel/locking/rtmutex.c:1430
 spin_unlock include/linux/spinlock_rt.h:109 [inline]
 d_alloc_parallel+0x103d/0x1630 fs/dcache.c:2826
 __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+0xd1e/0x18d0 fs/namei.c:2656
 path_openat+0x22c/0x37e0 fs/namei.c:4855
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_open_execat+0x12b/0x590 fs/exec.c:785
 alloc_bprm+0x28/0x660 fs/exec.c:1431
 class_bprm_constructor fs/exec.c:1496 [inline]
 kernel_execve+0x87/0x930 fs/exec.c:1889
 call_usermodehelper_exec_async+0x212/0x360 kernel/umh.c:109
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 1527:
 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:4614 [inline]
 slab_alloc_node mm/slub.c:4941 [inline]
 kmem_cache_alloc_lru_noprof+0x354/0x6b0 mm/slub.c:4974
 __d_alloc+0x37/0x6f0 fs/dcache.c:1902
 d_alloc_parallel+0xe3/0x1630 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+0xd1e/0x18d0 fs/namei.c:2656
 path_openat+0x22c/0x37e0 fs/namei.c:4855
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_open_execat+0x12b/0x590 fs/exec.c:785
 alloc_bprm+0x28/0x660 fs/exec.c:1431
 class_bprm_constructor fs/exec.c:1496 [inline]
 kernel_execve+0x87/0x930 fs/exec.c:1889
 call_usermodehelper_exec_async+0x212/0x360 kernel/umh.c:109
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

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:2699 [inline]
 slab_free mm/slub.c:6400 [inline]
 kmem_cache_free+0x187/0x6c0 mm/slub.c:6527
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core kernel/rcu/tree.c:2897 [inline]
 rcu_cpu_kthread+0x99e/0x1470 kernel/rcu/tree.c:2985
 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:3159 [inline]
 call_rcu+0xee/0x890 kernel/rcu/tree.c:3279
 dentry_kill+0x4ed/0x890 fs/dcache.c:845
 finish_dput+0x1a/0x260 fs/dcache.c:1001
 handle_mounts fs/namei.c:1753 [inline]
 step_into_slowpath+0x487/0x7e0 fs/namei.c:2104
 step_into fs/namei.c:2152 [inline]
 walk_component fs/namei.c:2288 [inline]
 link_path_walk+0xd50/0x18d0 fs/namei.c:2656
 path_openat+0x22c/0x37e0 fs/namei.c:4855
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_open_execat+0x12b/0x590 fs/exec.c:785
 alloc_bprm+0x28/0x660 fs/exec.c:1431
 class_bprm_constructor fs/exec.c:1496 [inline]
 kernel_execve+0x87/0x930 fs/exec.c:1889
 call_usermodehelper_exec_async+0x212/0x360 kernel/umh.c:109
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888023386370
 which belongs to the cache dentry of size 376
The buggy address is located 208 bytes inside of
 freed 376-byte region [ffff888023386370, ffff8880233864e8)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888023387130 pfn:0x23386
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000240(workingset|head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000240 ffff88801c2d3500 ffffea00008ce090 ffffea00008ce290
raw: ffff888023387130 000000080012000a 00000000f5000000 0000000000000000
head: 0080000000000240 ffff88801c2d3500 ffffea00008ce090 ffffea00008ce290
head: ffff888023387130 000000080012000a 00000000f5000000 0000000000000000
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 1486, tgid 1486 (kworker/u8:3), ts 13722633445, 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+0x265c/0x26e0 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3288 [inline]
 allocate_slab+0x76/0x5d0 mm/slub.c:3406
 new_slab mm/slub.c:3452 [inline]
 refill_objects+0x2d9/0x350 mm/slub.c:7333
 refill_sheaf mm/slub.c:2826 [inline]
 __pcs_replace_empty_main+0x331/0x690 mm/slub.c:4698
 alloc_from_pcs mm/slub.c:4796 [inline]
 slab_alloc_node mm/slub.c:4929 [inline]
 kmem_cache_alloc_lru_noprof+0x46b/0x6b0 mm/slub.c:4974
 __d_alloc+0x37/0x6f0 fs/dcache.c:1902
 d_alloc_parallel+0xe3/0x1630 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+0xd1e/0x18d0 fs/namei.c:2656
 path_openat+0x22c/0x37e0 fs/namei.c:4855
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_open_execat+0x12b/0x590 fs/exec.c:785
 alloc_bprm+0x28/0x660 fs/exec.c:1431
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888023386300: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fa fb
 ffff888023386380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888023386400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888023386480: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
 ffff888023386500: fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb
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