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BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:791 [inline]
BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:824 [inline]
BUG: KASAN: use-after-free in detach_if_pending+0x188/0x360 kernel/time/timer.c:841
Write of size 8 at addr ffff8881e7a3f1c8 by task syz-executor.4/2942

CPU: 1 PID: 2942 Comm: syz-executor.4 Tainted: G        W         5.4.274-syzkaller-00016-gdd432c37afcd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
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:2402
 netdev_run_todo+0xb7f/0xdf0 net/core/dev.c:9458
 tun_detach drivers/net/tun.c:766 [inline]
 tun_chr_close+0xc1/0x130 drivers/net/tun.c:3558
 __fput+0x262/0x680 fs/file_table.c:281
 task_work_run+0x140/0x170 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x190/0x1a0 arch/x86/entry/common.c:163
 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f633b9b1e5a
Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 03 7f 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 63 7f 02 00 8b 44 24
RSP: 002b:00007fff7511b6d0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 00007f633b9b1e5a
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007
RBP: 00007f633baeb980 R08: 0000000082316513 R09: 000000000000003f
R10: 0000000000000103 R11: 0000000000000293 R12: 000000000000f84d
R13: 00007f633baea05c R14: 0000000000000032 R15: 00007f633baeb980

Allocated by task 372:
 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
 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+0xd9/0x250 mm/slub.c:2842
 getname_flags+0xb8/0x4e0 fs/namei.c:141
 getname fs/namei.c:212 [inline]
 user_path_mountpoint_at+0x22/0x40 fs/namei.c:2842
 ksys_umount+0x143/0x410 fs/namespace.c:1690
 __do_sys_umount fs/namespace.c:1716 [inline]
 __se_sys_umount fs/namespace.c:1714 [inline]
 __x64_sys_umount+0x56/0x60 fs/namespace.c:1714
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 372:
 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+0x1b5/0x270 mm/kasan/common.c:487
 slab_free_hook mm/slub.c:1455 [inline]
 slab_free_freelist_hook mm/slub.c:1494 [inline]
 slab_free mm/slub.c:3080 [inline]
 kmem_cache_free+0x10b/0x2c0 mm/slub.c:3096
 putname fs/namei.c:262 [inline]
 filename_mountpoint+0x4cc/0x680 fs/namei.c:2820
 ksys_umount+0x143/0x410 fs/namespace.c:1690
 __do_sys_umount fs/namespace.c:1716 [inline]
 __se_sys_umount fs/namespace.c:1714 [inline]
 __x64_sys_umount+0x56/0x60 fs/namespace.c:1714
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

The buggy address belongs to the object at ffff8881e7a3e600
 which belongs to the cache names_cache of size 4096
The buggy address is located 3016 bytes inside of
 4096-byte region [ffff8881e7a3e600, ffff8881e7a3f600)
The buggy address belongs to the page:
page:ffffea00079e8e00 refcount:1 mapcount:0 mapping:ffff8881f5d05b80 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5d05b80
raw: 0000000000000000 0000000000070007 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]
 kmem_cache_alloc+0x109/0x250 mm/slub.c:2842
 getname_flags+0xb8/0x4e0 fs/namei.c:141
 getname fs/namei.c:212 [inline]
 __do_sys_unlink fs/namei.c:4259 [inline]
 __se_sys_unlink fs/namei.c:4257 [inline]
 __x64_sys_unlink+0x38/0x50 fs/namei.c:4257
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
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
 schedule+0x12c/0x1d0 kernel/sched/core.c:4375
 freezable_schedule include/linux/freezer.h:172 [inline]
 do_nanosleep+0x1c3/0x690 kernel/time/hrtimer.c:1938
 hrtimer_nanosleep+0x245/0x450 kernel/time/hrtimer.c:1991
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1231 [inline]
 __se_sys_clock_nanosleep+0x33c/0x3d0 kernel/time/posix-timers.c:1208
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Memory state around the buggy address:
 ffff8881e7a3f080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881e7a3f100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881e7a3f180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8881e7a3f200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881e7a3f280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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