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BUG: KASAN: slab-out-of-bounds in __write_once_size include/linux/compiler.h:295 [inline]
BUG: KASAN: slab-out-of-bounds in __hlist_del include/linux/list.h:789 [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+0x160/0x360 kernel/time/timer.c:841
Write of size 8 at addr ffff8881dbb531c0 by task syz-executor/12690

CPU: 1 PID: 12690 Comm: syz-executor 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
 __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+0x160/0x360 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
 __do_sys_exit_group kernel/exit.c:995 [inline]
 __se_sys_exit_group kernel/exit.c:993 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:993
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7fc2409ad169
Code: Bad RIP value.
RSP: 002b:00007ffe1fb0a708 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc2409ad169
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043
RBP: 00007fc240a0d8d0 R08: 00007ffe1fb084a7 R09: 0000000000000003
R10: 0000000000000009 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000003 R14: 00000000ffffffff R15: 00007ffe1fb0a8c0

Allocated by task 12757:
 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_node include/linux/slab.h:422 [inline]
 kmalloc_node include/linux/slab.h:599 [inline]
 kvmalloc_node+0x7e/0xf0 mm/util.c:596
 kvmalloc include/linux/mm.h:761 [inline]
 kvmalloc_array include/linux/mm.h:779 [inline]
 __ptr_ring_init_queue_alloc include/linux/ptr_ring.h:470 [inline]
 ptr_ring_init include/linux/ptr_ring.h:488 [inline]
 skb_array_init include/linux/skb_array.h:182 [inline]
 pfifo_fast_init+0x240/0x760 net/sched/sch_generic.c:784
 qdisc_create_dflt+0x129/0x250 net/sched/sch_generic.c:944
 mq_init+0x2c8/0x6b0 net/sched/sch_mq.c:90
 qdisc_create_dflt+0x129/0x250 net/sched/sch_generic.c:944
 attach_default_qdiscs net/sched/sch_generic.c:1113 [inline]
 dev_activate+0x11f/0xc00 net/sched/sch_generic.c:1154
 __dev_open+0x302/0x420 net/core/dev.c:1335
 __dev_change_flags+0x1db/0x6e0 net/core/dev.c:7958
 dev_change_flags+0x87/0x190 net/core/dev.c:8029
 dev_ifsioc+0x104/0xa60 net/core/dev_ioctl.c:226
 dev_ioctl+0x505/0xb40 net/core/dev_ioctl.c:483
 sock_do_ioctl+0x295/0x3a0 net/socket.c:1081
 sock_ioctl+0x4a4/0x760 net/socket.c:1198
 do_vfs_ioctl+0x742/0x1720 fs/ioctl.c:47
 ksys_ioctl fs/ioctl.c:742 [inline]
 __do_sys_ioctl fs/ioctl.c:749 [inline]
 __se_sys_ioctl fs/ioctl.c:747 [inline]
 __x64_sys_ioctl+0xd4/0x110 fs/ioctl.c:747
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 12752:
 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]
 kfree+0x123/0x370 mm/slub.c:4071
 ptr_ring_cleanup include/linux/ptr_ring.h:670 [inline]
 pfifo_fast_destroy+0x82/0xd0 net/sched/sch_generic.c:810
 qdisc_destroy+0xd2/0x490 net/sched/sch_generic.c:1008
 qdisc_put net/sched/sch_generic.c:1035 [inline]
 shutdown_scheduler_queue net/sched/sch_generic.c:1372 [inline]
 netdev_for_each_tx_queue include/linux/netdevice.h:2194 [inline]
 dev_shutdown+0x18a/0x540 net/sched/sch_generic.c:1378
 rollback_registered_many+0x87d/0x1330 net/core/dev.c:8643
 rollback_registered net/core/dev.c:8692 [inline]
 unregister_netdevice_queue+0x333/0x500 net/core/dev.c:9786
 unregister_netdevice include/linux/netdevice.h:2726 [inline]
 __tun_detach+0x8de/0x1390 drivers/net/tun.c:747
 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
 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

The buggy address belongs to the object at ffff8881dbb52000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 448 bytes to the right of
 4096-byte region [ffff8881dbb52000, ffff8881dbb53000)
The buggy address belongs to the page:
page:ffffea00076ed400 refcount:1 mapcount:0 mapping:ffff8881f5c0c280 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c0c280
raw: 0000000000000000 0000000000040004 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_node include/linux/slab.h:422 [inline]
 kmalloc_node include/linux/slab.h:599 [inline]
 kvmalloc_node+0x7e/0xf0 mm/util.c:596
 kvmalloc include/linux/mm.h:761 [inline]
 kvmalloc_array include/linux/mm.h:779 [inline]
 __ptr_ring_init_queue_alloc include/linux/ptr_ring.h:470 [inline]
 ptr_ring_init include/linux/ptr_ring.h:488 [inline]
 skb_array_init include/linux/skb_array.h:182 [inline]
 pfifo_fast_init+0x377/0x760 net/sched/sch_generic.c:784
 qdisc_create_dflt+0x129/0x250 net/sched/sch_generic.c:944
 mq_init+0x2c8/0x6b0 net/sched/sch_mq.c:90
 qdisc_create_dflt+0x129/0x250 net/sched/sch_generic.c:944
 attach_default_qdiscs net/sched/sch_generic.c:1113 [inline]
 dev_activate+0x11f/0xc00 net/sched/sch_generic.c:1154
 __dev_open+0x302/0x420 net/core/dev.c:1335
 __dev_change_flags+0x1db/0x6e0 net/core/dev.c:7958
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_pcp_prepare mm/page_alloc.c:1233 [inline]
 free_unref_page_prepare+0x297/0x380 mm/page_alloc.c:3085
 free_unref_page mm/page_alloc.c:3134 [inline]
 free_the_page mm/page_alloc.c:4953 [inline]
 __free_pages+0xaf/0x140 mm/page_alloc.c:4961
 __vunmap+0x75b/0x890 mm/vmalloc.c:2260
 kcov_mmap+0x8c/0x120 kernel/kcov.c:474
 call_mmap include/linux/fs.h:1996 [inline]
 mmap_region+0x110d/0x16f0 mm/mmap.c:1812
 do_mmap+0x822/0xd30 mm/mmap.c:1581
 do_mmap_pgoff include/linux/mm.h:2480 [inline]
 vm_mmap_pgoff+0x1b5/0x260 mm/util.c:528
 ksys_mmap_pgoff+0x168/0x1e0 mm/mmap.c:1631
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Memory state around the buggy address:
 ffff8881dbb53080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881dbb53100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881dbb53180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                           ^
 ffff8881dbb53200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881dbb53280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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