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BUG: KASAN: use-after-free in mutex_can_spin_on_owner kernel/locking/mutex.c:617 [inline]
BUG: KASAN: use-after-free in mutex_optimistic_spin kernel/locking/mutex.c:661 [inline]
BUG: KASAN: use-after-free in __mutex_lock_common kernel/locking/mutex.c:973 [inline]
BUG: KASAN: use-after-free in __mutex_lock+0xace/0xe30 kernel/locking/mutex.c:1114
Read of size 4 at addr ffff8881e6df6e78 by task syz.3.757/3534

CPU: 1 PID: 3534 Comm: syz.3.757 Not tainted 5.4.292-syzkaller-00021-gcd8e74fa0fa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 __dump_stack+0x1e/0x20 lib/dump_stack.c:77
 dump_stack+0x15b/0x1b8 lib/dump_stack.c:118
 print_address_description+0x8d/0x4c0 mm/kasan/report.c:384
 __kasan_report+0xef/0x120 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131
 mutex_can_spin_on_owner kernel/locking/mutex.c:617 [inline]
 mutex_optimistic_spin kernel/locking/mutex.c:661 [inline]
 __mutex_lock_common kernel/locking/mutex.c:973 [inline]
 __mutex_lock+0xace/0xe30 kernel/locking/mutex.c:1114
 __mutex_lock_killable_slowpath+0xe/0x10 kernel/locking/mutex.c:1381
 mutex_lock_killable+0xd3/0xe0 kernel/locking/mutex.c:1348
 lo_open+0x1d/0xc0 drivers/block/loop.c:1899
 __blkdev_get+0x610/0x1560 fs/block_dev.c:1581
 blkdev_get+0xcb/0x380 fs/block_dev.c:1714
 blkdev_get_by_path+0x1e9/0x2d0 fs/block_dev.c:1776
 mount_bdev+0x50/0x390 fs/super.c:1386
 ext4_mount+0x34/0x40 fs/ext4/super.c:6279
 legacy_get_tree+0xea/0x190 fs/fs_context.c:648
 vfs_get_tree+0x89/0x260 fs/super.c:1558
 vfs_fsconfig_locked+0x236/0x3f0 fs/fsopen.c:232
 __do_sys_fsconfig fs/fsopen.c:445 [inline]
 __se_sys_fsconfig+0x66e/0x7b0 fs/fsopen.c:314
 __x64_sys_fsconfig+0xbf/0xd0 fs/fsopen.c:314
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f0668180969
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:00007f06667e9038 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
RAX: ffffffffffffffda RBX: 00007f06683a7fa0 RCX: 00007f0668180969
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005
RBP: 00007f0668202ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f06683a7fa0 R15: 00007fffa00bb168

Allocated by task 3448:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 __kasan_kmalloc+0x162/0x200 mm/kasan/common.c:529
 kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:537
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slub.c:2829 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0xe2/0x270 mm/slub.c:2842
 kmem_cache_alloc_node include/linux/slab.h:427 [inline]
 alloc_task_struct_node kernel/fork.c:171 [inline]
 dup_task_struct+0x57/0x640 kernel/fork.c:882
 copy_process+0x503/0x2cf0 kernel/fork.c:1889
 _do_fork+0x190/0x860 kernel/fork.c:2399
 __do_sys_clone3 kernel/fork.c:2688 [inline]
 __se_sys_clone3 kernel/fork.c:2675 [inline]
 __x64_sys_clone3+0x1de/0x1f0 kernel/fork.c:2675
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 17:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 kasan_set_free_info mm/kasan/common.c:345 [inline]
 __kasan_slab_free+0x1c3/0x280 mm/kasan/common.c:487
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:496
 slab_free_hook mm/slub.c:1455 [inline]
 slab_free_freelist_hook+0xb7/0x180 mm/slub.c:1494
 slab_free mm/slub.c:3080 [inline]
 kmem_cache_free+0x10c/0x2c0 mm/slub.c:3096
 free_task_struct kernel/fork.c:176 [inline]
 free_task+0xe9/0x150 kernel/fork.c:480
 __put_task_struct+0x2b7/0x420 kernel/fork.c:755
 put_task_struct include/linux/sched/task.h:147 [inline]
 delayed_put_task_struct+0x71/0x210 kernel/exit.c:229
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch+0x446/0x980 kernel/rcu/tree.c:2167
 rcu_core+0x4bd/0xbd0 kernel/rcu/tree.c:2387
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2396
 __do_softirq+0x236/0x660 kernel/softirq.c:292

The buggy address belongs to the object at ffff8881e6df6e40
 which belongs to the cache task_struct of size 3904
The buggy address is located 56 bytes inside of
 3904-byte region [ffff8881e6df6e40, ffff8881e6df7d80)
The buggy address belongs to the page:
page:ffffea00079b7c00 refcount:1 mapcount:0 mapping:ffff8881f5cf5180 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5cf5180
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x35e/0x370 mm/page_alloc.c:2171
 get_page_from_freelist+0x1296/0x1310 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x202/0x4b0 mm/page_alloc.c:4894
 alloc_slab_page+0x3c/0x3b0 mm/slub.c:343
 allocate_slab mm/slub.c:1683 [inline]
 new_slab+0x93/0x420 mm/slub.c:1749
 new_slab_objects mm/slub.c:2505 [inline]
 ___slab_alloc+0x29e/0x420 mm/slub.c:2667
 __slab_alloc+0x63/0xa0 mm/slub.c:2707
 slab_alloc_node mm/slub.c:2792 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0x12c/0x270 mm/slub.c:2842
 kmem_cache_alloc_node include/linux/slab.h:427 [inline]
 alloc_task_struct_node kernel/fork.c:171 [inline]
 dup_task_struct+0x57/0x640 kernel/fork.c:882
 copy_process+0x503/0x2cf0 kernel/fork.c:1889
 _do_fork+0x190/0x860 kernel/fork.c:2399
 kernel_thread+0x6f/0x90 kernel/fork.c:2489
 create_kthread kernel/kthread.c:311 [inline]
 kthreadd+0x354/0x480 kernel/kthread.c:654
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1176 [inline]
 __free_pages_ok+0x7e4/0x910 mm/page_alloc.c:1438
 free_the_page mm/page_alloc.c:4956 [inline]
 __free_pages+0x8c/0x110 mm/page_alloc.c:4962
 __free_slab+0x218/0x2d0 mm/slub.c:1774
 free_slab mm/slub.c:1789 [inline]
 discard_slab mm/slub.c:1795 [inline]
 unfreeze_partials+0x165/0x1a0 mm/slub.c:2288
 put_cpu_partial+0xc1/0x180 mm/slub.c:2324
 __slab_free+0x2be/0x380 mm/slub.c:2971
 do_slab_free mm/slub.c:3068 [inline]
 ___cache_free+0xbb/0xd0 mm/slub.c:3087
 qlink_free+0x23/0x30 mm/kasan/quarantine.c:148
 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:167
 quarantine_reduce+0x1a8/0x200 mm/kasan/quarantine.c:260
 __kasan_kmalloc+0x42/0x200 mm/kasan/common.c:507
 kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:537
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slub.c:2829 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0xe2/0x270 mm/slub.c:2842
 getname_flags+0xb9/0x500 fs/namei.c:141
 user_path_at_empty+0x2f/0x50 fs/namei.c:2703
 user_path_at include/linux/namei.h:49 [inline]
 vfs_statx+0x116/0x200 fs/stat.c:187

Memory state around the buggy address:
 ffff8881e6df6d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881e6df6d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8881e6df6e00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                                ^
 ffff8881e6df6e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881e6df6f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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