KASAN: use-after-free Read in ipvlan_queue_xmit (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3c8c2309 Linux 4.19.190
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=144518a3d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=d3c2572d41264a3d
dashboard link: https://syzkaller.appspot.com/bug?extid=efee3dc8792f4e1b8242
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11cdf963d00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=116bf9b3d00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+efee3d...@syzkaller.appspotmail.com

IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready
batman_adv: batadv0: Interface activated: batadv_slave_1
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
==================================================================
BUG: KASAN: use-after-free in ether_addr_equal include/linux/etherdevice.h:321 [inline]
BUG: KASAN: use-after-free in ipvlan_xmit_mode_l2 drivers/net/ipvlan/ipvlan_core.c:605 [inline]
BUG: KASAN: use-after-free in ipvlan_queue_xmit+0x9d2/0x18e0 drivers/net/ipvlan/ipvlan_core.c:651
Read of size 4 at addr ffff888098aead3f by task syz-executor100/8320

CPU: 1 PID: 8320 Comm: syz-executor100 Not tainted 4.19.190-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+0x1fc/0x2ef lib/dump_stack.c:118
print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354
kasan_report mm/kasan/report.c:412 [inline]
__asan_report_load4_noabort+0x88/0x90 mm/kasan/report.c:432
ether_addr_equal include/linux/etherdevice.h:321 [inline]
ipvlan_xmit_mode_l2 drivers/net/ipvlan/ipvlan_core.c:605 [inline]
ipvlan_queue_xmit+0x9d2/0x18e0 drivers/net/ipvlan/ipvlan_core.c:651
ipvlan_start_xmit+0x4f/0x190 drivers/net/ipvlan/ipvlan_main.c:290
__netdev_start_xmit include/linux/netdevice.h:4345 [inline]
netdev_start_xmit include/linux/netdevice.h:4359 [inline]
dev_direct_xmit+0x3f9/0x6d0 net/core/dev.c:3905
packet_snd net/packet/af_packet.c:2988 [inline]
packet_sendmsg+0x24e9/0x7130 net/packet/af_packet.c:3013
sock_sendmsg_nosec net/socket.c:622 [inline]
sock_sendmsg+0xc3/0x120 net/socket.c:632
__sys_sendto+0x21a/0x320 net/socket.c:1787
__do_sys_sendto net/socket.c:1799 [inline]
__se_sys_sendto net/socket.c:1795 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:1795
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x443a99
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd89b8d218 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000443a99
RDX: 000000000000000e RSI: 0000000020000080 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000020000040 R09: 0000000000000014
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd89b8d240
R13: 00000000000f4240 R14: 00000000004b8018 R15: 00000000004004b8

The buggy address belongs to the page:
page:ffffea000262ba80 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfff00000000000()
raw: 00fff00000000000 ffffea0002bcf5c8 ffffea0002d23bc8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff888098aeac00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888098aeac80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888098aead00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff888098aead80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888098aeae00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


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