KASAN: use-after-free Write in skb_release_data

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: dda0e292 Linux 4.19.114
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=124aabb3e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=f32ac7e5b2d5c341
dashboard link: https://syzkaller.appspot.com/bug?extid=abaca368ab2c7ed92288
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+abaca3...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in atomic_sub_return include/asm-generic/atomic-instrumented.h:305 [inline]
BUG: KASAN: use-after-free in skb_release_data+0x119/0x8c0 net/core/skbuff.c:563
Write of size 4 at addr ffff8880a9e273a0 by task syz-executor.2/13304

CPU: 1 PID: 13304 Comm: syz-executor.2 Not tainted 4.19.114-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+0x188/0x20d lib/dump_stack.c:118
print_address_description.cold+0x7c/0x212 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+0x88/0x2b9 mm/kasan/report.c:396
atomic_sub_return include/asm-generic/atomic-instrumented.h:305 [inline]
skb_release_data+0x119/0x8c0 net/core/skbuff.c:563
skb_release_all+0x46/0x60 net/core/skbuff.c:631
8021q: adding VLAN 0 to HW filter on device bond1
__kfree_skb net/core/skbuff.c:645 [inline]
kfree_skb net/core/skbuff.c:663 [inline]
kfree_skb+0xe1/0x390 net/core/skbuff.c:657
sit_tunnel_xmit net/ipv6/sit.c:1053 [inline]
sit_tunnel_xmit+0x359/0x26ab net/ipv6/sit.c:1027
__netdev_start_xmit include/linux/netdevice.h:4314 [inline]
netdev_start_xmit include/linux/netdevice.h:4323 [inline]
xmit_one net/core/dev.c:3258 [inline]
dev_hard_start_xmit+0x1a4/0x950 net/core/dev.c:3274
__dev_queue_xmit+0x270f/0x3040 net/core/dev.c:3844
bond0: Enslaving bond1 as an active interface with an up link
packet_sendmsg_spkt+0xdc0/0x14a0 net/packet/af_packet.c:1982
sock_sendmsg_nosec net/socket.c:622 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:632
__sys_sendto+0x21a/0x330 net/socket.c:1787
nvme_fabrics: unknown parameter or missing value ' ' in ctrl creation request
__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: 0033:0x45c889
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:00007f757284dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f757284e6d4 RCX: 000000000045c889
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000076bf00 R08: 0000000020000240 R09: 0000000000000080
R10: 0000000000000806 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000a04 R14: 00000000004ccbf3 R15: 000000000076bf0c

Allocated by task 13304:
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc mm/kasan/kasan.c:553 [inline]
kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:531
__do_kmalloc_node mm/slab.c:3689 [inline]
__kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3703
__kmalloc_reserve.isra.0+0x39/0xe0 net/core/skbuff.c:137
__alloc_skb+0xef/0x5b0 net/core/skbuff.c:205
alloc_skb include/linux/skbuff.h:995 [inline]
sock_wmalloc+0xd0/0x120 net/core/sock.c:1940
packet_sendmsg_spkt+0x420/0x14a0 net/packet/af_packet.c:1929
sock_sendmsg_nosec net/socket.c:622 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:632
__sys_sendto+0x21a/0x330 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

Freed by task 13304:
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0xf7/0x140 mm/kasan/kasan.c:521
__cache_free mm/slab.c:3503 [inline]
kfree+0xce/0x220 mm/slab.c:3822
skb_free_head+0x91/0xb0 net/core/skbuff.c:554
skb_release_data+0x600/0x8c0 net/core/skbuff.c:574
skb_release_all+0x46/0x60 net/core/skbuff.c:631
__kfree_skb net/core/skbuff.c:645 [inline]
consume_skb net/core/skbuff.c:705 [inline]
consume_skb+0xda/0x380 net/core/skbuff.c:699
packet_rcv+0xea/0x1500 net/packet/af_packet.c:2146
dev_queue_xmit_nit+0x74b/0xa00 net/core/dev.c:2054
xmit_one net/core/dev.c:3254 [inline]
dev_hard_start_xmit+0xa6/0x950 net/core/dev.c:3274
__dev_queue_xmit+0x270f/0x3040 net/core/dev.c:3844
packet_sendmsg_spkt+0xdc0/0x14a0 net/packet/af_packet.c:1982
sock_sendmsg_nosec net/socket.c:622 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:632
__sys_sendto+0x21a/0x330 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

The buggy address belongs to the object at ffff8880a9e272c0
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 224 bytes inside of
512-byte region [ffff8880a9e272c0, ffff8880a9e274c0)
The buggy address belongs to the page:
page:ffffea0002a789c0 count:1 mapcount:0 mapping:ffff88812c3dc940 index:0xffff8880a9e27040
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffffea000284c5c8 ffffea0002798648 ffff88812c3dc940
raw: ffff8880a9e27040 ffff8880a9e27040 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8880a9e27280: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
ffff8880a9e27300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a9e27380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880a9e27400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880a9e27480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.