syzbot

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BUG: KASAN: slab-use-after-free in list_empty include/linux/list.h:381 [inline]
BUG: KASAN: slab-use-after-free in locks_remove_posix+0x10f/0x630 fs/locks.c:2667
Read of size 8 at addr ffff88803421a730 by task syz.1.758/8190

CPU: 0 UID: 0 PID: 8190 Comm: syz.1.758 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 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
 list_empty include/linux/list.h:381 [inline]
 locks_remove_posix+0x10f/0x630 fs/locks.c:2667
 filp_flush+0x113/0x190 fs/open.c:1537
 filp_close+0x1d/0x40 fs/open.c:1546
 __range_close fs/file.c:790 [inline]
 __do_sys_close_range fs/file.c:849 [inline]
 __se_sys_close_range+0x359/0x650 fs/file.c:813
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5efd18f749
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:00007ffc028fdaa8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 000000000002e0bd RCX: 00007f5efd18f749
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f5efd3e7da0 R08: 0000000000000001 R09: 00000007028fdd9f
R10: 0000001b2fd20000 R11: 0000000000000246 R12: 00007f5efd3e609c
R13: 00007f5efd3e6090 R14: ffffffffffffffff R15: 00007ffc028fdbc0
 </TASK>

Allocated by task 8192:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:339 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:365
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4948 [inline]
 slab_alloc_node mm/slub.c:5258 [inline]
 kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5265
 locks_get_lock_context+0x134/0x3b0 fs/locks.c:186
 generic_add_lease fs/locks.c:1811 [inline]
 generic_setlease+0x528/0x1280 fs/locks.c:1970
 do_fcntl_add_lease+0x34d/0x460 fs/locks.c:2073
 fcntl_setlease+0x123/0x180 fs/locks.c:2098
 do_fcntl+0x867/0x1a50 fs/fcntl.c:535
 __do_sys_fcntl fs/fcntl.c:602 [inline]
 __se_sys_fcntl+0xc8/0x150 fs/fcntl.c:587
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 8192:
 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:6663 [inline]
 kmem_cache_free+0x197/0x620 mm/slub.c:6774
 __destroy_inode+0x2ea/0x670 fs/inode.c:373
 destroy_inode fs/inode.c:394 [inline]
 evict+0x87d/0xae0 fs/inode.c:861
 __dentry_kill+0x209/0x660 fs/dcache.c:670
 finish_dput+0xc9/0x480 fs/dcache.c:879
 path_put+0x39/0x60 fs/namei.c:665
 mqueue_file_open ipc/mqueue.c:912 [inline]
 do_mq_open+0x468/0x7c0 ipc/mqueue.c:928
 __do_sys_mq_open ipc/mqueue.c:941 [inline]
 __se_sys_mq_open ipc/mqueue.c:934 [inline]
 __x64_sys_mq_open+0x16a/0x1c0 ipc/mqueue.c:934
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88803421a6e0
 which belongs to the cache file_lock_ctx of size 112
The buggy address is located 80 bytes inside of
 freed 112-byte region [ffff88803421a6e0, ffff88803421a750)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88803421a630 pfn:0x3421a
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801de88140 dead000000000122 0000000000000000
raw: ffff88803421a630 0000000080170015 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5202, tgid 5202 (udevd), ts 53593121643, free_ts 53591654313
 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+0x2365/0x2440 mm/page_alloc.c:3915
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
 alloc_pages_mpol+0x232/0x4a0 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+0xf2b/0x1960 mm/slub.c:4651
 __slab_alloc+0x65/0x100 mm/slub.c:4774
 __slab_alloc_node mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:5246 [inline]
 kmem_cache_alloc_noprof+0x40f/0x710 mm/slub.c:5265
 locks_get_lock_context+0x134/0x3b0 fs/locks.c:186
 flock_lock_inode+0xf2/0x1410 fs/locks.c:1083
 flock_lock_inode_wait fs/locks.c:2134 [inline]
 locks_lock_inode_wait+0x107/0x410 fs/locks.c:2161
 locks_lock_file_wait include/linux/filelock.h:446 [inline]
 __do_sys_flock fs/locks.c:2229 [inline]
 __se_sys_flock+0x467/0x5b0 fs/locks.c:2185
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 15 tgid 15 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core+0xd70/0x1870 kernel/rcu/tree.c:2857
 handle_softirqs+0x27d/0x850 kernel/softirq.c:626
 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:1067
 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Memory state around the buggy address:
 ffff88803421a600: fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb
 ffff88803421a680: fb fb fb fb fc fc fc fc fc fc fc fc fa fb fb fb
>ffff88803421a700: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc
                                     ^
 ffff88803421a780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88803421a800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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