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BUG: KASAN: use-after-free in __get_unaligned_cpu32 include/linux/unaligned/packed_struct.h:19 [inline]
BUG: KASAN: use-after-free in mc_hash drivers/net/macvlan.c:255 [inline]
BUG: KASAN: use-after-free in macvlan_broadcast+0x57c/0x660 drivers/net/macvlan.c:281
Read of size 4 at addr ffff88808ecfb081 by task syz-executor.4/31257

CPU: 1 PID: 31257 Comm: syz-executor.4 Not tainted 4.19.93-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report mm/kasan/report.c:412 [inline]
 kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:443
 __get_unaligned_cpu32 include/linux/unaligned/packed_struct.h:19 [inline]
 mc_hash drivers/net/macvlan.c:255 [inline]
 macvlan_broadcast+0x57c/0x660 drivers/net/macvlan.c:281
 macvlan_queue_xmit drivers/net/macvlan.c:524 [inline]
 macvlan_start_xmit+0x408/0x785 drivers/net/macvlan.c:563
 __netdev_start_xmit include/linux/netdevice.h:4308 [inline]
 netdev_start_xmit include/linux/netdevice.h:4317 [inline]
 dev_direct_xmit+0x34d/0x650 net/core/dev.c:3909
 packet_direct_xmit+0xf9/0x170 net/packet/af_packet.c:246
 packet_snd net/packet/af_packet.c:2958 [inline]
 packet_sendmsg+0x3bb2/0x6440 net/packet/af_packet.c:2983
 sock_sendmsg_nosec net/socket.c:622 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:632
 __sys_sendto+0x262/0x380 net/socket.c:1787
 __do_sys_sendto net/socket.c:1799 [inline]
 __se_sys_sendto net/socket.c:1795 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1795
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45af49
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f99531ffc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 000000000045af49
RDX: 000000000000000e RSI: 0000000020000080 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f99532006d4
R13: 00000000004ca8a7 R14: 00000000004e3ac0 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea00023b3ec0 count:0 mapcount:-128 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000000()
raw: 00fffe0000000000 ffffea0002823908 ffffea00022a3848 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808ecfaf80: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
 ffff88808ecfb000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
kobject: 'loop1' (00000000edf1c11f): kobject_uevent_env
>ffff88808ecfb080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88808ecfb100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88808ecfb180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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