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BUG: KASAN: use-after-free in atomic_fetch_add include/asm-generic/atomic-instrumented.h:111 [inline]
BUG: KASAN: use-after-free in refcount_add include/linux/refcount.h:188 [inline]
BUG: KASAN: use-after-free in refcount_inc include/linux/refcount.h:228 [inline]
BUG: KASAN: use-after-free in get_task_struct include/linux/sched/task.h:111 [inline]
BUG: KASAN: use-after-free in kthread_stop+0x32/0x460 kernel/kthread.c:612
Write of size 4 at addr ffff8881db840020 by task syz-executor365/309

CPU: 0 PID: 309 Comm: syz-executor365 Not tainted 5.4.210-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18e/0x1d5 lib/dump_stack.c:118
 print_address_description+0x8c/0x630 mm/kasan/report.c:384
 __kasan_report+0xf6/0x130 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 check_memory_region_inline mm/kasan/generic.c:141 [inline]
 check_memory_region+0x298/0x2d0 mm/kasan/generic.c:191
 atomic_fetch_add include/asm-generic/atomic-instrumented.h:111 [inline]
 refcount_add include/linux/refcount.h:188 [inline]
 refcount_inc include/linux/refcount.h:228 [inline]
 get_task_struct include/linux/sched/task.h:111 [inline]
 kthread_stop+0x32/0x460 kernel/kthread.c:612
 ext4_put_super+0x789/0xbc0 fs/ext4/super.c:1055
 generic_shutdown_super+0x11b/0x2a0 fs/super.c:464
 kill_block_super+0x79/0xd0 fs/super.c:1444
 deactivate_locked_super+0xaf/0x100 fs/super.c:335
 deactivate_super+0x168/0x210 fs/super.c:366
 cleanup_mnt+0x432/0x4e0 fs/namespace.c:1102
 task_work_run+0x186/0x1b0 kernel/task_work.c:113
 ptrace_notify+0x1f3/0x290 kernel/signal.c:2271
 ptrace_report_syscall include/linux/tracehook.h:66 [inline]
 tracehook_report_syscall_exit include/linux/tracehook.h:129 [inline]
 syscall_slow_exit_work+0x167/0x3e0 arch/x86/entry/common.c:246
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x19e/0x1c0 arch/x86/entry/common.c:300
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fb230faa327
Code: ff d0 48 89 c7 b8 3c 00 00 00 0f 05 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc1822e558 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fb230faa327
RDX: 00007ffc1822e619 RSI: 000000000000000a RDI: 00007ffc1822e610
RBP: 00007ffc1822e610 R08: 00000000ffffffff R09: 00007ffc1822e3f0
R10: 00005555556dc653 R11: 0000000000000202 R12: 00007ffc1822f6d0
R13: 00005555556dc5f0 R14: 00007ffc1822e580 R15: 00007ffc1822f6f0

Allocated by task 2:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 __kasan_kmalloc+0x131/0x1e0 mm/kasan/common.c:529
 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+0xd0/0x210 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+0x4f/0x5a0 kernel/fork.c:871
 copy_process+0x4c3/0x31f0 kernel/fork.c:1878
 _do_fork+0x142/0x7f0 kernel/fork.c:2391
 kernel_thread+0x109/0x150 kernel/fork.c:2481
 create_kthread kernel/kthread.c:311 [inline]
 kthreadd+0x35d/0x4a0 kernel/kthread.c:654
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

Freed by task 10:
 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+0x178/0x240 mm/kasan/common.c:487
 slab_free_hook mm/slub.c:1455 [inline]
 slab_free_freelist_hook+0x80/0x150 mm/slub.c:1494
 slab_free mm/slub.c:3080 [inline]
 kmem_cache_free+0xa9/0x1d0 mm/slub.c:3096
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch+0x41c/0x910 kernel/rcu/tree.c:2167
 rcu_core+0x448/0xbc0 kernel/rcu/tree.c:2387
 __do_softirq+0x23e/0x643 kernel/softirq.c:292

The buggy address belongs to the object at ffff8881db840000
 which belongs to the cache task_struct of size 3904
The buggy address is located 32 bytes inside of
 3904-byte region [ffff8881db840000, ffff8881db840f40)
The buggy address belongs to the page:
page:ffffea00076e1000 refcount:1 mapcount:0 mapping:ffff8881f5cec780 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5cec780
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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x194/0x380 mm/page_alloc.c:2171
 get_page_from_freelist+0x524/0x560 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x2ab/0x6f0 mm/page_alloc.c:4857
 alloc_slab_page+0x39/0x3e0 mm/slub.c:343
 allocate_slab mm/slub.c:1683 [inline]
 new_slab+0x97/0x450 mm/slub.c:1749
 new_slab_objects mm/slub.c:2505 [inline]
 ___slab_alloc+0x320/0x4a0 mm/slub.c:2667
 __slab_alloc+0x5a/0x90 mm/slub.c:2707
 slab_alloc_node mm/slub.c:2792 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0x100/0x210 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+0x4f/0x5a0 kernel/fork.c:871
 copy_process+0x4c3/0x31f0 kernel/fork.c:1878
 _do_fork+0x142/0x7f0 kernel/fork.c:2391
 kernel_thread+0x109/0x150 kernel/fork.c:2481
 create_kthread kernel/kthread.c:311 [inline]
 kthreadd+0x35d/0x4a0 kernel/kthread.c:654
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8881db83ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881db83ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881db840000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff8881db840080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881db840100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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