EXT4-fs (loop0): mounted filesystem without journal. Opts: journal_dev=0x0000000000000003,inode_readahead_blks=0x0000000008000000,quota,noload,user_xattr,mblk_io_submit,noinit_itable,noblock_validity,max_dir_size_kb=0x0000000000000009,init_itable=0x0000000000000fff,,errors=continue. Quota mode: writeback.
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
BUG: KASAN: use-after-free in netif_running include/linux/netdevice.h:3788 [inline]
BUG: KASAN: use-after-free in enqueue_to_backlog+0x139/0xb20 net/core/dev.c:4741
Read of size 8 at addr ffff8881274e0038 by task syz.0.178/841

CPU: 0 PID: 841 Comm: syz.0.178 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0x10f/0x150 mm/kasan/report.c:444
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189
 __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 netif_running include/linux/netdevice.h:3788 [inline]
 enqueue_to_backlog+0x139/0xb20 net/core/dev.c:4741
 netif_rx_internal+0xb3/0x370 net/core/dev.c:5025
 netif_rx_ni+0x2d/0x2a0 net/core/dev.c:5066
 dev_loopback_xmit+0x32d/0x480 net/core/dev.c:4015
 ip_mc_finish_output+0x186/0x3f0 net/ipv4/ip_output.c:355
 NF_HOOK include/linux/netfilter.h:305 [inline]
 ip_mc_output+0x24a/0x8d0 net/ipv4/ip_output.c:394
 dst_output include/net/dst.h:453 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 ip_send_skb+0xb4/0x140 net/ipv4/ip_output.c:1594
 udp_send_skb+0x8e6/0x10f0 net/ipv4/udp.c:991
 udp_sendmsg+0x176a/0x2110 net/ipv4/udp.c:1279
 inet_sendmsg+0xa5/0xc0 net/ipv4/af_inet.c:830
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x5be/0x8f0 net/socket.c:2436
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2490
 __sys_sendmmsg+0x2ba/0x4e0 net/socket.c:2576
 __do_sys_sendmmsg net/socket.c:2605 [inline]
 __se_sys_sendmmsg net/socket.c:2602 [inline]
 __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2602
 x64_sys_call+0x6c6/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:308
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe777bdb159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe776634028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007fe777e62fa0 RCX: 00007fe777bdb159
RDX: 000000000800001d RSI: 0000200000007fc0 RDI: 0000000000000006
RBP: 00007fe777c7206b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000300 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe777e63038 R14: 00007fe777e62fa0 R15: 00007fffdbb8de68
 </TASK>

The buggy address belongs to the page:
page:ffffea00049d3800 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1274e0
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea0004586f08 ffff8881f703c5f0 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x446dc0(GFP_KERNEL_ACCOUNT|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_COMP|__GFP_ZERO), pid 285, ts 24546393630, free_ts 56152694366
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2607
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2613
 get_page_from_freelist+0x2c3a/0x2cd0 mm/page_alloc.c:4487
 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5824
 __alloc_pages_node include/linux/gfp.h:595 [inline]
 alloc_pages_node include/linux/gfp.h:609 [inline]
 alloc_pages include/linux/gfp.h:622 [inline]
 kmalloc_order+0x4c/0x160 mm/slab_common.c:995
 kmalloc_order_trace+0x18/0xb0 mm/slab_common.c:1014
 kmalloc_large include/linux/slab.h:548 [inline]
 __kmalloc+0x199/0x2c0 mm/slub.c:4425
 __kmalloc_node include/linux/slab.h:487 [inline]
 kmalloc_node include/linux/slab.h:642 [inline]
 kvmalloc_node+0x211/0x320 mm/util.c:621
 kvmalloc include/linux/mm.h:862 [inline]
 kvzalloc include/linux/mm.h:870 [inline]
 alloc_netdev_mqs+0x8d/0xe20 net/core/dev.c:10926
 tun_set_iff+0x55d/0xe70 drivers/net/tun.c:2787
 __tun_chr_ioctl+0x870/0x1f40 drivers/net/tun.c:3076
 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3363
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0x121/0x1a0 fs/ioctl.c:860
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:860
 x64_sys_call+0x2f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1474 [inline]
 free_pcp_prepare mm/page_alloc.c:1546 [inline]
 free_unref_page_prepare+0x5fa/0x600 mm/page_alloc.c:3536
 free_unref_page+0xae/0x540 mm/page_alloc.c:3618
 free_the_page mm/page_alloc.c:805 [inline]
 __free_pages+0x6c/0x100 mm/page_alloc.c:5900
 free_nonslab_page+0x86/0xc0 mm/slub.c:3564
 kfree+0x19a/0x270 mm/slub.c:4585
 kvfree+0x35/0x40 mm/util.c:661
 netdev_freemem+0x3f/0x60 net/core/dev.c:10880
 netdev_release+0x7f/0xb0 net/core/net-sysfs.c:1903
 device_release+0x96/0x1c0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:713 [inline]
 kobject_release lib/kobject.c:744 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x18a/0x270 lib/kobject.c:761
 netdev_run_todo+0x7dc/0x950 net/core/dev.c:10736
 rtnl_unlock net/core/rtnetlink.c:112 [inline]
 rtnetlink_rcv_msg+0xa38/0xcb0 net/core/rtnetlink.c:5663
 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2520
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5680
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x86c/0xa30 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x879/0xb80 net/netlink/af_netlink.c:1923

Memory state around the buggy address:
 ffff8881274dff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881274dff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881274e0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                        ^
 ffff8881274e0080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881274e0100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================