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BUG: KASAN: slab-out-of-bounds in __hlist_del include/linux/list.h:791 [inline]
BUG: KASAN: slab-out-of-bounds in detach_timer kernel/time/timer.c:824 [inline]
BUG: KASAN: slab-out-of-bounds in detach_if_pending+0x188/0x360 kernel/time/timer.c:841
Write of size 8 at addr ffff8881e4c5b1c8 by task syz.1.617/2615

CPU: 0 PID: 2615 Comm: syz.1.617 Not tainted 5.4.290-syzkaller-00017-g6b07fcd94a6a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d8/0x241 lib/dump_stack.c:118
 print_address_description+0x8c/0x600 mm/kasan/report.c:384
 __kasan_report+0xf3/0x120 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 __hlist_del include/linux/list.h:791 [inline]
 detach_timer kernel/time/timer.c:824 [inline]
 detach_if_pending+0x188/0x360 kernel/time/timer.c:841
 try_to_del_timer_sync kernel/time/timer.c:1267 [inline]
 del_timer_sync+0x13c/0x230 kernel/time/timer.c:1410
 tun_flow_uninit+0x2c/0x280 drivers/net/tun.c:1452
 tun_free_netdev+0x77/0x190 drivers/net/tun.c:2404
 netdev_run_todo+0xb7f/0xdf0 net/core/dev.c:9477
 tun_detach drivers/net/tun.c:766 [inline]
 tun_chr_close+0xc1/0x130 drivers/net/tun.c:3563
 __fput+0x262/0x680 fs/file_table.c:281
 task_work_run+0x140/0x170 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xcaf/0x2bc0 kernel/exit.c:861
 do_group_exit+0x138/0x300 kernel/exit.c:984
 get_signal+0xdb1/0x1440 kernel/signal.c:2738
 do_signal+0xb0/0x11f0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0xc0/0x1a0 arch/x86/entry/common.c:159
 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f932cb78169
Code: Bad RIP value.
RSP: 002b:00007f932b1a00e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f932cd91168 RCX: 00007f932cb78169
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f932cd9116c
RBP: 00007f932cd91160 R08: 00007fffe22d20b0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f932cd9116c
R13: 0000000000000000 R14: 00007fffe2289810 R15: 00007fffe22898f8

Allocated by task 2596:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 __kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529
 kmalloc_array include/linux/slab.h:618 [inline]
 realloc_stack_state kernel/bpf/verifier.c:595 [inline]
 realloc_func_state+0x2ee/0x5a0 kernel/bpf/verifier.c:611
 copy_func_state kernel/bpf/verifier.c:704 [inline]
 copy_verifier_state+0x655/0xbf0 kernel/bpf/verifier.c:751
 push_stack+0x153/0x470 kernel/bpf/verifier.c:819
 check_cond_jmp_op+0x719/0x17d0 kernel/bpf/verifier.c:6192
 do_check+0x4ba1/0x9820 kernel/bpf/verifier.c:8109
 bpf_check+0x2183/0xb3e0 kernel/bpf/verifier.c:9637
 bpf_prog_load kernel/bpf/syscall.c:1724 [inline]
 __do_sys_bpf kernel/bpf/syscall.c:2891 [inline]
 __se_sys_bpf+0x8139/0xbcb0 kernel/bpf/syscall.c:2849
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8881e4c58000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 4552 bytes to the right of
 8192-byte region [ffff8881e4c58000, ffff8881e4c5a000)
The buggy address belongs to the page:
page:ffffea0007931600 refcount:1 mapcount:0 mapping:ffff8881f5c0c500 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c0c500
raw: 0000000000000000 0000000000020002 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+0x18f/0x370 mm/page_alloc.c:2171
 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4893
 alloc_slab_page+0x39/0x3c0 mm/slub.c:343
 allocate_slab mm/slub.c:1683 [inline]
 new_slab+0x97/0x440 mm/slub.c:1749
 new_slab_objects mm/slub.c:2505 [inline]
 ___slab_alloc+0x2fe/0x490 mm/slub.c:2667
 __slab_alloc+0x62/0xa0 mm/slub.c:2707
 slab_alloc_node mm/slub.c:2792 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 __kmalloc+0x19b/0x2e0 mm/slub.c:3909
 kmalloc_array include/linux/slab.h:618 [inline]
 realloc_stack_state kernel/bpf/verifier.c:595 [inline]
 realloc_func_state+0x2ee/0x5a0 kernel/bpf/verifier.c:611
 copy_func_state kernel/bpf/verifier.c:704 [inline]
 copy_verifier_state+0x655/0xbf0 kernel/bpf/verifier.c:751
 push_stack+0x153/0x470 kernel/bpf/verifier.c:819
 check_cond_jmp_op+0x719/0x17d0 kernel/bpf/verifier.c:6192
 do_check+0x4ba1/0x9820 kernel/bpf/verifier.c:8109
 bpf_check+0x2183/0xb3e0 kernel/bpf/verifier.c:9637
 bpf_prog_load kernel/bpf/syscall.c:1724 [inline]
 __do_sys_bpf kernel/bpf/syscall.c:2891 [inline]
 __se_sys_bpf+0x8139/0xbcb0 kernel/bpf/syscall.c:2849
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
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+0x847/0x950 mm/page_alloc.c:1438
 free_the_page mm/page_alloc.c:4955 [inline]
 __free_pages+0x91/0x140 mm/page_alloc.c:4961
 free_thread_stack kernel/fork.c:299 [inline]
 release_task_stack kernel/fork.c:439 [inline]
 put_task_stack+0x212/0x260 kernel/fork.c:450
 finish_task_switch+0x24a/0x590 kernel/sched/core.c:3479
 context_switch kernel/sched/core.c:3611 [inline]
 __schedule+0xb0d/0x1320 kernel/sched/core.c:4307
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:4456
 preempt_schedule+0xd9/0xe0 kernel/sched/core.c:4481
 ___preempt_schedule+0x16/0x20 arch/x86/entry/thunk_64.S:50
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
 _raw_spin_unlock_irqrestore+0x6f/0x80 kernel/locking/spinlock.c:191
 spin_unlock_irqrestore include/linux/spinlock.h:393 [inline]
 prepare_to_wait_event+0x3c1/0x420 kernel/sched/wait.c:300
 synchronize_rcu_expedited+0x4e7/0x660 kernel/rcu/tree_exp.h:834
 __tun_detach+0x8ed/0x1390 drivers/net/tun.c:731
 tun_detach drivers/net/tun.c:763 [inline]
 tun_chr_close+0x8f/0x130 drivers/net/tun.c:3563
 __fput+0x262/0x680 fs/file_table.c:281
 task_work_run+0x140/0x170 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xcaf/0x2bc0 kernel/exit.c:861

Memory state around the buggy address:
 ffff8881e4c5b080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881e4c5b100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881e4c5b180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                              ^
 ffff8881e4c5b200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881e4c5b280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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