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BUG: KASAN: use-after-free in __write_once_size include/linux/compiler.h:295 [inline]
BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:789 [inline]
BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:824 [inline]
BUG: KASAN: use-after-free in detach_if_pending+0x12d/0x330 kernel/time/timer.c:841
Write of size 8 at addr ffff8881d62871c0 by task syz.9.550/2321

CPU: 1 PID: 2321 Comm: syz.9.550 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_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:137
 __write_once_size include/linux/compiler.h:295 [inline]
 __hlist_del include/linux/list.h:789 [inline]
 detach_timer kernel/time/timer.c:824 [inline]
 detach_if_pending+0x12d/0x330 kernel/time/timer.c:841
 try_to_del_timer_sync kernel/time/timer.c:1267 [inline]
 del_timer_sync+0x136/0x1a0 kernel/time/timer.c:1410
 tun_flow_uninit+0x2f/0x2b0 drivers/net/tun.c:1452
 tun_free_netdev+0x7a/0x1b0 drivers/net/tun.c:2404
 netdev_run_todo+0xa45/0xc70 net/core/dev.c:9477
 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112
 tun_detach drivers/net/tun.c:766 [inline]
 tun_chr_close+0xc4/0x140 drivers/net/tun.c:3563
 __fput+0x2a3/0x730 fs/file_table.c:281
 ____fput+0x15/0x20 fs/file_table.c:314
 task_work_run+0x146/0x170 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x195/0x1b0 arch/x86/entry/common.c:163
 prepare_exit_to_usermode+0x18e/0x1f0 arch/x86/entry/common.c:194
 syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
 do_syscall_64+0x13e/0x170 arch/x86/entry/common.c:300
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f731013c5ca
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 43 91 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 a3 91 02 00 8b 44 24
RSP: 002b:00007ffd1744b0f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 000000000000000f RCX: 00007f731013c5ca
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000000e
RBP: 00007f7310366ba0 R08: 0000000000000001 R09: 0000001d1744b3ff
R10: 00007f730ffaf000 R11: 0000000000000293 R12: 00007f7310364fac
R13: 00007f7310364fa0 R14: ffffffffffffffff R15: 00007ffd1744b220

The buggy address belongs to the page:
page:ffffea000758a1c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8881e8b90b00
flags: 0x8000000000000000()
raw: 8000000000000000 dead000000000100 dead000000000122 0000000000000000
raw: ffff8881e8b90b00 0000000000000000 00000001ffffffff 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 0x102cc2(GFP_HIGHUSER|__GFP_NOWARN)
 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_pages include/linux/gfp.h:503 [inline]
 __alloc_pages_node include/linux/gfp.h:516 [inline]
 alloc_pages_node include/linux/gfp.h:530 [inline]
 pcpu_alloc_pages mm/percpu-vm.c:94 [inline]
 pcpu_populate_chunk+0x1b6/0xce0 mm/percpu-vm.c:284
 pcpu_alloc+0x8ec/0x1120 mm/percpu.c:1714
 __alloc_percpu_gfp+0x25/0x30 mm/percpu.c:1783
 prealloc_init+0x24b/0x810 kernel/bpf/hashtab.c:154
 htab_map_alloc+0x65f/0x940 kernel/bpf/hashtab.c:385
 find_and_alloc_map kernel/bpf/syscall.c:122 [inline]
 map_create+0x2d8/0x980 kernel/bpf/syscall.c:573
 __do_sys_bpf kernel/bpf/syscall.c:2873 [inline]
 __se_sys_bpf+0x2dc/0x570 kernel/bpf/syscall.c:2849
 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:2849
 do_syscall_64+0xcf/0x170 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+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
 kfree+0x1ca/0x260 mm/slub.c:4068
 kvfree+0x4c/0x50 mm/util.c:625
 bpf_check+0x8371/0x9cf0 kernel/bpf/verifier.c:9731
 bpf_prog_load+0xa5f/0xe10 kernel/bpf/syscall.c:1724
 __do_sys_bpf kernel/bpf/syscall.c:2891 [inline]
 __se_sys_bpf+0x435/0x570 kernel/bpf/syscall.c:2849
 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:2849
 do_syscall_64+0xcf/0x170 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Memory state around the buggy address:
 ffff8881d6287080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881d6287100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881d6287180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                           ^
 ffff8881d6287200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881d6287280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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