Hello,
syzbot found the following crash on:
HEAD commit: e40a826a6cbc qed: Add support for virtual link.
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=168954a5400000
kernel config: https://syzkaller.appspot.com/x/.config?x=7e7e2279c0020d5f
dashboard link: https://syzkaller.appspot.com/bug?extid=580be3953ed99133804f
compiler: gcc (GCC) 8.0.1 20180413 (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: [email protected]
==================================================================
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+0x1a3/0x880
net/core/skbuff.c:559
Write of size 4 at addr ffff8801d8cb4120 by task syz-executor0/8395
CPU: 0 PID: 8395 Comm: syz-executor0 Not tainted 4.19.0-rc6+ #254
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+0x1c4/0x2b4 lib/dump_stack.c:113
print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
check_memory_region_inline mm/kasan/kasan.c:260 [inline]
check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278
atomic_sub_return include/asm-generic/atomic-instrumented.h:305 [inline]
skb_release_data+0x1a3/0x880 net/core/skbuff.c:559
skb_release_all+0x4a/0x60 net/core/skbuff.c:627
__kfree_skb net/core/skbuff.c:641 [inline]
kfree_skb+0x1bb/0x580 net/core/skbuff.c:659
sit_tunnel_xmit+0x173/0x30d0 net/ipv6/sit.c:1044
__netdev_start_xmit include/linux/netdevice.h:4328 [inline]
netdev_start_xmit include/linux/netdevice.h:4337 [inline]
xmit_one net/core/dev.c:3219 [inline]
dev_hard_start_xmit+0x295/0xc90 net/core/dev.c:3235
__dev_queue_xmit+0x2f0d/0x3950 net/core/dev.c:3805
dev_queue_xmit+0x17/0x20 net/core/dev.c:3838
packet_sendmsg_spkt+0xf44/0x16f0 net/packet/af_packet.c:1975
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:631
___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
__sys_sendmsg+0x11d/0x280 net/socket.c:2154
__do_sys_sendmsg net/socket.c:2163 [inline]
__se_sys_sendmsg net/socket.c:2161 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457519
Code: 1d b4 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 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2a52d30c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457519
RDX: 0000000000000000 RSI: 00000000200003c0 RDI: 0000000000000003
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2a52d316d4
R13: 00000000004c34d5 R14: 00000000004d52c8 R15: 00000000ffffffff
Allocated by task 8395:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
__do_kmalloc_node mm/slab.c:3682 [inline]
__kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3696
__kmalloc_reserve.isra.39+0x41/0xe0 net/core/skbuff.c:137
__alloc_skb+0x155/0x770 net/core/skbuff.c:205
alloc_skb include/linux/skbuff.h:997 [inline]
sock_wmalloc+0x16d/0x1f0 net/core/sock.c:1934
packet_sendmsg_spkt+0x48a/0x16f0 net/packet/af_packet.c:1922
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:631
___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
__sys_sendmsg+0x11d/0x280 net/socket.c:2154
__do_sys_sendmsg net/socket.c:2163 [inline]
__se_sys_sendmsg net/socket.c:2161 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 8395:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kfree+0xcf/0x230 mm/slab.c:3813
skb_free_head+0x99/0xc0 net/core/skbuff.c:550
skb_release_data+0x6a4/0x880 net/core/skbuff.c:570
skb_release_all+0x4a/0x60 net/core/skbuff.c:627
__kfree_skb net/core/skbuff.c:641 [inline]
consume_skb+0x1ae/0x570 net/core/skbuff.c:701
packet_rcv+0x172/0x1820 net/packet/af_packet.c:2139
dev_queue_xmit_nit+0x8ae/0xb30 net/core/dev.c:2020
xmit_one net/core/dev.c:3215 [inline]
dev_hard_start_xmit+0x186/0xc90 net/core/dev.c:3235
__dev_queue_xmit+0x2f0d/0x3950 net/core/dev.c:3805
dev_queue_xmit+0x17/0x20 net/core/dev.c:3838
packet_sendmsg_spkt+0xf44/0x16f0 net/packet/af_packet.c:1975
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:631
___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
__sys_sendmsg+0x11d/0x280 net/socket.c:2154
__do_sys_sendmsg net/socket.c:2163 [inline]
__se_sys_sendmsg net/socket.c:2161 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The buggy address belongs to the object at ffff8801d8cb4040
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 224 bytes inside of
512-byte region [ffff8801d8cb4040, ffff8801d8cb4240)
The buggy address belongs to the page:
page:ffffea0007632d00 count:1 mapcount:0 mapping:ffff8801da800940
index:0xffff8801d8cb42c0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea00070baf08 ffffea000736a788 ffff8801da800940
raw: ffff8801d8cb42c0 ffff8801d8cb4040 0000000100000005 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8801d8cb4000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
ffff8801d8cb4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8801d8cb4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8801d8cb4180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801d8cb4200: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at [email protected].
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
syzbot.
On Mon, Oct 15, 2018 at 8:30 AM, syzbot
<[email protected]> wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: e40a826a6cbc qed: Add support for virtual link.
> git tree: net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=168954a5400000
> kernel config: https://syzkaller.appspot.com/x/.config?x=7e7e2279c0020d5f
> dashboard link: https://syzkaller.appspot.com/bug?extid=580be3953ed99133804f
> compiler: gcc (GCC) 8.0.1 20180413 (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: [email protected]
>
> ==================================================================
> 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+0x1a3/0x880
> net/core/skbuff.c:559
> Write of size 4 at addr ffff8801d8cb4120 by task syz-executor0/8395
>
> CPU: 0 PID: 8395 Comm: syz-executor0 Not tainted 4.19.0-rc6+ #254
> 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+0x1c4/0x2b4 lib/dump_stack.c:113
> print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
> kasan_report_error mm/kasan/report.c:354 [inline]
> kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
> check_memory_region_inline mm/kasan/kasan.c:260 [inline]
> check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
> kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278
> atomic_sub_return include/asm-generic/atomic-instrumented.h:305 [inline]
> skb_release_data+0x1a3/0x880 net/core/skbuff.c:559
> skb_release_all+0x4a/0x60 net/core/skbuff.c:627
> __kfree_skb net/core/skbuff.c:641 [inline]
> kfree_skb+0x1bb/0x580 net/core/skbuff.c:659
> sit_tunnel_xmit+0x173/0x30d0 net/ipv6/sit.c:1044
> __netdev_start_xmit include/linux/netdevice.h:4328 [inline]
> netdev_start_xmit include/linux/netdevice.h:4337 [inline]
> xmit_one net/core/dev.c:3219 [inline]
> dev_hard_start_xmit+0x295/0xc90 net/core/dev.c:3235
> __dev_queue_xmit+0x2f0d/0x3950 net/core/dev.c:3805
> dev_queue_xmit+0x17/0x20 net/core/dev.c:3838
> packet_sendmsg_spkt+0xf44/0x16f0 net/packet/af_packet.c:1975
> sock_sendmsg_nosec net/socket.c:621 [inline]
> sock_sendmsg+0xd5/0x120 net/socket.c:631
> ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
> __sys_sendmsg+0x11d/0x280 net/socket.c:2154
> __do_sys_sendmsg net/socket.c:2163 [inline]
> __se_sys_sendmsg net/socket.c:2161 [inline]
> __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x457519
> Code: 1d b4 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 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007f2a52d30c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457519
> RDX: 0000000000000000 RSI: 00000000200003c0 RDI: 0000000000000003
> RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2a52d316d4
> R13: 00000000004c34d5 R14: 00000000004d52c8 R15: 00000000ffffffff
>
> Allocated by task 8395:
> save_stack+0x43/0xd0 mm/kasan/kasan.c:448
> set_track mm/kasan/kasan.c:460 [inline]
> kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
> __do_kmalloc_node mm/slab.c:3682 [inline]
> __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3696
> __kmalloc_reserve.isra.39+0x41/0xe0 net/core/skbuff.c:137
> __alloc_skb+0x155/0x770 net/core/skbuff.c:205
> alloc_skb include/linux/skbuff.h:997 [inline]
> sock_wmalloc+0x16d/0x1f0 net/core/sock.c:1934
> packet_sendmsg_spkt+0x48a/0x16f0 net/packet/af_packet.c:1922
> sock_sendmsg_nosec net/socket.c:621 [inline]
> sock_sendmsg+0xd5/0x120 net/socket.c:631
> ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
> __sys_sendmsg+0x11d/0x280 net/socket.c:2154
> __do_sys_sendmsg net/socket.c:2163 [inline]
> __se_sys_sendmsg net/socket.c:2161 [inline]
> __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> Freed by task 8395:
> save_stack+0x43/0xd0 mm/kasan/kasan.c:448
> set_track mm/kasan/kasan.c:460 [inline]
> __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
> kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
> __cache_free mm/slab.c:3498 [inline]
> kfree+0xcf/0x230 mm/slab.c:3813
> skb_free_head+0x99/0xc0 net/core/skbuff.c:550
> skb_release_data+0x6a4/0x880 net/core/skbuff.c:570
> skb_release_all+0x4a/0x60 net/core/skbuff.c:627
> __kfree_skb net/core/skbuff.c:641 [inline]
> consume_skb+0x1ae/0x570 net/core/skbuff.c:701
> packet_rcv+0x172/0x1820 net/packet/af_packet.c:2139
> dev_queue_xmit_nit+0x8ae/0xb30 net/core/dev.c:2020
> xmit_one net/core/dev.c:3215 [inline]
> dev_hard_start_xmit+0x186/0xc90 net/core/dev.c:3235
> __dev_queue_xmit+0x2f0d/0x3950 net/core/dev.c:3805
> dev_queue_xmit+0x17/0x20 net/core/dev.c:3838
> packet_sendmsg_spkt+0xf44/0x16f0 net/packet/af_packet.c:1975
> sock_sendmsg_nosec net/socket.c:621 [inline]
> sock_sendmsg+0xd5/0x120 net/socket.c:631
> ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
> __sys_sendmsg+0x11d/0x280 net/socket.c:2154
> __do_sys_sendmsg net/socket.c:2163 [inline]
> __se_sys_sendmsg net/socket.c:2161 [inline]
> __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> The buggy address belongs to the object at ffff8801d8cb4040
> which belongs to the cache kmalloc-512 of size 512
> The buggy address is located 224 bytes inside of
> 512-byte region [ffff8801d8cb4040, ffff8801d8cb4240)
> The buggy address belongs to the page:
> page:ffffea0007632d00 count:1 mapcount:0 mapping:ffff8801da800940
> index:0xffff8801d8cb42c0
> flags: 0x2fffc0000000100(slab)
> raw: 02fffc0000000100 ffffea00070baf08 ffffea000736a788 ffff8801da800940
> raw: ffff8801d8cb42c0 ffff8801d8cb4040 0000000100000005 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
> ffff8801d8cb4000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
> ffff8801d8cb4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>
>> ffff8801d8cb4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>
> ^
> ffff8801d8cb4180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8801d8cb4200: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
> ==================================================================
FWIW from the log this was triggered on this program:
05:22:33 executing program 0:
r0 = socket(0x11, 0xa, 0x0)
sendmsg(r0, &(0x7f00000003c0)={&(0x7f00000000c0)=@pptp={0x18, 0x2,
{0x0, @dev}}, 0x80, &(0x7f0000000380), 0x0, &(0x7f0000001880)}, 0x0)
Looks like a race with a very short inconsistency window since it was
triggered only once.
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at [email protected].
>
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
> syzbot.
syzbot has found a reproducer for the following crash on:
HEAD commit: 68cc2999 Merge branch 'devlink-small-spring-cleanup'
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13737c07200000
kernel config: https://syzkaller.appspot.com/x/.config?x=9ab5bbbbf283c99a
dashboard link: https://syzkaller.appspot.com/bug?extid=580be3953ed99133804f
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=123a3d3b200000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11d34f93200000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email protected]
==================================================================
BUG: KASAN: use-after-free in atomic_sub_return
include/asm-generic/atomic-instrumented.h:159 [inline]
BUG: KASAN: use-after-free in skb_release_data+0x11d/0x7a0
net/core/skbuff.c:566
Write of size 4 at addr ffff88808dee74e0 by task syz-executor887/7877
CPU: 0 PID: 7877 Comm: syz-executor887 Not tainted 5.0.0+ #108
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+0x172/0x1f0 lib/dump_stack.c:113
print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
check_memory_region_inline mm/kasan/generic.c:185 [inline]
check_memory_region+0x123/0x190 mm/kasan/generic.c:191
kasan_check_write+0x14/0x20 mm/kasan/common.c:108
atomic_sub_return include/asm-generic/atomic-instrumented.h:159 [inline]
skb_release_data+0x11d/0x7a0 net/core/skbuff.c:566
skb_release_all+0x4d/0x60 net/core/skbuff.c:631
__kfree_skb net/core/skbuff.c:645 [inline]
kfree_skb net/core/skbuff.c:663 [inline]
kfree_skb+0xe8/0x390 net/core/skbuff.c:657
skb_queue_purge+0x19/0x40 net/core/skbuff.c:2906
packet_release+0x8eb/0xbf0 net/packet/af_packet.c:3026
__sock_release+0xd3/0x2b0 net/socket.c:599
sock_close+0x1b/0x30 net/socket.c:1247
__fput+0x2e5/0x8d0 fs/file_table.c:278
____fput+0x16/0x20 fs/file_table.c:309
task_work_run+0x14a/0x1c0 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x90a/0x2fa0 kernel/exit.c:876
do_group_exit+0x135/0x370 kernel/exit.c:980
get_signal+0x399/0x1d50 kernel/signal.c:2575
do_signal+0x87/0x1940 arch/x86/kernel/signal.c:816
exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4474d9
Code: 7a 6c 69 62 77 00 73 74 72 65 61 6d 2e 63 00 6f 70 65 6e 20 65 72 72
6f 72 20 25 64 2c 20 66 69 6c 65 20 27 25 73 27 3a 20 25 <73> 0a 00 66 69
6c 65 20 25 64 20 69 73 20 61 20 74 74 79 2d 74 79
RSP: 002b:00007f7ce163fdb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00000000006ddc38 RCX: 00000000004474d9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00000000006ddc38
RBP: 00000000006ddc30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006ddc3c
R13: 00007ffe04f36bbf R14: 00007f7ce16409c0 R15: 000000000000002d
Allocated by task 7876:
save_stack+0x45/0xd0 mm/kasan/common.c:75
set_track mm/kasan/common.c:87 [inline]
__kasan_kmalloc mm/kasan/common.c:497 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:511
__do_kmalloc_node mm/slab.c:3686 [inline]
__kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3700
__kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:140
__alloc_skb+0x10b/0x5e0 net/core/skbuff.c:208
alloc_skb_fclone include/linux/skbuff.h:1107 [inline]
sk_stream_alloc_skb+0x113/0xd10 net/ipv4/tcp.c:889
tcp_connect+0xfd8/0x4280 net/ipv4/tcp_output.c:3521
tcp_v4_connect+0x1514/0x1c40 net/ipv4/tcp_ipv4.c:315
__inet_stream_connect+0x83f/0xea0 net/ipv4/af_inet.c:659
tcp_sendmsg_fastopen net/ipv4/tcp.c:1158 [inline]
tcp_sendmsg_locked+0x2314/0x34d0 net/ipv4/tcp.c:1200
tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1434
inet_sendmsg+0x147/0x5e0 net/ipv4/af_inet.c:802
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xdd/0x130 net/socket.c:661
__sys_sendto+0x262/0x380 net/socket.c:1932
__do_sys_sendto net/socket.c:1944 [inline]
__se_sys_sendto net/socket.c:1940 [inline]
__x64_sys_sendto+0xe1/0x1a0 net/socket.c:1940
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 7877:
save_stack+0x45/0xd0 mm/kasan/common.c:75
set_track mm/kasan/common.c:87 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:459
kasan_slab_free+0xe/0x10 mm/kasan/common.c:467
__cache_free mm/slab.c:3498 [inline]
kfree+0xcf/0x230 mm/slab.c:3821
skb_free_head+0x93/0xb0 net/core/skbuff.c:557
skb_release_data+0x576/0x7a0 net/core/skbuff.c:577
skb_release_all+0x4d/0x60 net/core/skbuff.c:631
__kfree_skb net/core/skbuff.c:645 [inline]
kfree_skb net/core/skbuff.c:663 [inline]
kfree_skb+0xe8/0x390 net/core/skbuff.c:657
skb_queue_purge+0x19/0x40 net/core/skbuff.c:2906
packet_release+0x8eb/0xbf0 net/packet/af_packet.c:3026
__sock_release+0xd3/0x2b0 net/socket.c:599
sock_close+0x1b/0x30 net/socket.c:1247
__fput+0x2e5/0x8d0 fs/file_table.c:278
____fput+0x16/0x20 fs/file_table.c:309
task_work_run+0x14a/0x1c0 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x90a/0x2fa0 kernel/exit.c:876
do_group_exit+0x135/0x370 kernel/exit.c:980
get_signal+0x399/0x1d50 kernel/signal.c:2575
do_signal+0x87/0x1940 arch/x86/kernel/signal.c:816
exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The buggy address belongs to the object at ffff88808dee7200
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 736 bytes inside of
1024-byte region [ffff88808dee7200, ffff88808dee7600)
The buggy address belongs to the page:
page:ffffea000237b980 count:1 mapcount:0 mapping:ffff88812c3f0ac0 index:0x0
compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea000224ba08 ffffea0002a63288 ffff88812c3f0ac0
raw: 0000000000000000 ffff88808dee6000 0000000100000007 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88808dee7380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88808dee7400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff88808dee7480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88808dee7500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88808dee7580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
syzbot has bisected this bug to:
commit 472c2e07eef045145bc1493cc94a01c87140780a
Author: Eric Dumazet <[email protected]>
Date: Fri Mar 22 15:56:39 2019 +0000
tcp: add one skb cache for tx
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17abf52b200000
start commit: 68cc2999 Merge branch 'devlink-small-spring-cleanup'
git tree: net-next
final crash: https://syzkaller.appspot.com/x/report.txt?x=146bf52b200000
console output: https://syzkaller.appspot.com/x/log.txt?x=106bf52b200000
kernel config: https://syzkaller.appspot.com/x/.config?x=9ab5bbbbf283c99a
dashboard link: https://syzkaller.appspot.com/bug?extid=580be3953ed99133804f
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=123a3d3b200000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11d34f93200000
Reported-by: [email protected]
Fixes: 472c2e07eef0 ("tcp: add one skb cache for tx")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
On Mon, Mar 25, 2019 at 1:19 AM syzbot
<[email protected]> wrote:
>
> syzbot has bisected this bug to:
>
> commit 472c2e07eef045145bc1493cc94a01c87140780a
> Author: Eric Dumazet <[email protected]>
> Date: Fri Mar 22 15:56:39 2019 +0000
>
> tcp: add one skb cache for tx
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17abf52b200000
> start commit: 68cc2999 Merge branch 'devlink-small-spring-cleanup'
> git tree: net-next
> final crash: https://syzkaller.appspot.com/x/report.txt?x=146bf52b200000
> console output: https://syzkaller.appspot.com/x/log.txt?x=106bf52b200000
> kernel config: https://syzkaller.appspot.com/x/.config?x=9ab5bbbbf283c99a
> dashboard link: https://syzkaller.appspot.com/bug?extid=580be3953ed99133804f
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=123a3d3b200000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11d34f93200000
>
> Reported-by: [email protected]
> Fixes: 472c2e07eef0 ("tcp: add one skb cache for tx")
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
This bisection makes no sense, the original bug report was in in
October last year.
This was :
Hello,
syzbot found the following crash on:
HEAD commit: e40a826a6cbc qed: Add support for virtual link.
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=168954a5400000
kernel config: https://syzkaller.appspot.com/x/.config?x=7e7e2279c0020d5f
dashboard link: https://syzkaller.appspot.com/bug?extid=580be3953ed99133804f
compiler: gcc (GCC) 8.0.1 20180413 (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: [email protected]
==================================================================
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+0x1a3/0x880 net/core/skbuff.c:559
Write of size 4 at addr ffff8801d8cb4120 by task syz-executor0/8395
CPU: 0 PID: 8395 Comm: syz-executor0 Not tainted 4.19.0-rc6+ #254
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+0x1c4/0x2b4 lib/dump_stack.c:113
print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
check_memory_region_inline mm/kasan/kasan.c:260 [inline]
check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278
atomic_sub_return include/asm-generic/atomic-instrumented.h:305 [inline]
skb_release_data+0x1a3/0x880 net/core/skbuff.c:559
skb_release_all+0x4a/0x60 net/core/skbuff.c:627
__kfree_skb net/core/skbuff.c:641 [inline]
kfree_skb+0x1bb/0x580 net/core/skbuff.c:659
sit_tunnel_xmit+0x173/0x30d0 net/ipv6/sit.c:1044
__netdev_start_xmit include/linux/netdevice.h:4328 [inline]
netdev_start_xmit include/linux/netdevice.h:4337 [inline]
xmit_one net/core/dev.c:3219 [inline]
dev_hard_start_xmit+0x295/0xc90 net/core/dev.c:3235
__dev_queue_xmit+0x2f0d/0x3950 net/core/dev.c:3805
dev_queue_xmit+0x17/0x20 net/core/dev.c:3838
packet_sendmsg_spkt+0xf44/0x16f0 net/packet/af_packet.c:1975
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:631
___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
__sys_sendmsg+0x11d/0x280 net/socket.c:2154
__do_sys_sendmsg net/socket.c:2163 [inline]
__se_sys_sendmsg net/socket.c:2161 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457519
Code: 1d b4 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 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2a52d30c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457519
RDX: 0000000000000000 RSI: 00000000200003c0 RDI: 0000000000000003
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2a52d316d4
R13: 00000000004c34d5 R14: 00000000004d52c8 R15: 00000000ffffffff
Allocated by task 8395:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
__do_kmalloc_node mm/slab.c:3682 [inline]
__kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3696
__kmalloc_reserve.isra.39+0x41/0xe0 net/core/skbuff.c:137
__alloc_skb+0x155/0x770 net/core/skbuff.c:205
alloc_skb include/linux/skbuff.h:997 [inline]
sock_wmalloc+0x16d/0x1f0 net/core/sock.c:1934
packet_sendmsg_spkt+0x48a/0x16f0 net/packet/af_packet.c:1922
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:631
___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
__sys_sendmsg+0x11d/0x280 net/socket.c:2154
__do_sys_sendmsg net/socket.c:2163 [inline]
__se_sys_sendmsg net/socket.c:2161 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 8395:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kfree+0xcf/0x230 mm/slab.c:3813
skb_free_head+0x99/0xc0 net/core/skbuff.c:550
skb_release_data+0x6a4/0x880 net/core/skbuff.c:570
skb_release_all+0x4a/0x60 net/core/skbuff.c:627
__kfree_skb net/core/skbuff.c:641 [inline]
consume_skb+0x1ae/0x570 net/core/skbuff.c:701
packet_rcv+0x172/0x1820 net/packet/af_packet.c:2139
dev_queue_xmit_nit+0x8ae/0xb30 net/core/dev.c:2020
xmit_one net/core/dev.c:3215 [inline]
dev_hard_start_xmit+0x186/0xc90 net/core/dev.c:3235
__dev_queue_xmit+0x2f0d/0x3950 net/core/dev.c:3805
dev_queue_xmit+0x17/0x20 net/core/dev.c:3838
packet_sendmsg_spkt+0xf44/0x16f0 net/packet/af_packet.c:1975
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:631
___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
__sys_sendmsg+0x11d/0x280 net/socket.c:2154
__do_sys_sendmsg net/socket.c:2163 [inline]
__se_sys_sendmsg net/socket.c:2161 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The buggy address belongs to the object at ffff8801d8cb4040
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 224 bytes inside of
512-byte region [ffff8801d8cb4040, ffff8801d8cb4240)
The buggy address belongs to the page:
page:ffffea0007632d00 count:1 mapcount:0 mapping:ffff8801da800940
index:0xffff8801d8cb42c0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea00070baf08 ffffea000736a788 ffff8801da800940
raw: ffff8801d8cb42c0 ffff8801d8cb4040 0000000100000005 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8801d8cb4000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
ffff8801d8cb4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801d8cb4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8801d8cb4180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801d8cb4200: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at [email protected].
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot.
On Mon, Mar 25, 2019 at 9:36 AM Eric Dumazet <[email protected]> wrote:
>
> On Mon, Mar 25, 2019 at 1:19 AM syzbot
> <[email protected]> wrote:
> >
> > syzbot has bisected this bug to:
> >
> > commit 472c2e07eef045145bc1493cc94a01c87140780a
> > Author: Eric Dumazet <[email protected]>
> > Date: Fri Mar 22 15:56:39 2019 +0000
> >
> > tcp: add one skb cache for tx
> >
> > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17abf52b200000
> > start commit: 68cc2999 Merge branch 'devlink-small-spring-cleanup'
> > git tree: net-next
> > final crash: https://syzkaller.appspot.com/x/report.txt?x=146bf52b200000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=106bf52b200000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=9ab5bbbbf283c99a
> > dashboard link: https://syzkaller.appspot.com/bug?extid=580be3953ed99133804f
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=123a3d3b200000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11d34f93200000
> >
> > Reported-by: [email protected]
> > Fixes: 472c2e07eef0 ("tcp: add one skb cache for tx")
> >
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
> This bisection makes no sense, the original bug report was in in
> October last year.
But the bisection log itself looks legit and seem to point to a legit
bug, right?. If so, let's fix the new bug in the context of this
report. Or the old one. Both. Any.
The more we let hundreds of kernel bugs pile up without attention,
then more of such glued bugs we will unavoidably have...
> This was :
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: e40a826a6cbc qed: Add support for virtual link.
> git tree: net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=168954a5400000
> kernel config: https://syzkaller.appspot.com/x/.config?x=7e7e2279c0020d5f
> dashboard link: https://syzkaller.appspot.com/bug?extid=580be3953ed99133804f
> compiler: gcc (GCC) 8.0.1 20180413 (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: [email protected]
>
> ==================================================================
> 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+0x1a3/0x880 net/core/skbuff.c:559
> Write of size 4 at addr ffff8801d8cb4120 by task syz-executor0/8395
>
> CPU: 0 PID: 8395 Comm: syz-executor0 Not tainted 4.19.0-rc6+ #254
> 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+0x1c4/0x2b4 lib/dump_stack.c:113
> print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
> kasan_report_error mm/kasan/report.c:354 [inline]
> kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
> check_memory_region_inline mm/kasan/kasan.c:260 [inline]
> check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
> kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278
> atomic_sub_return include/asm-generic/atomic-instrumented.h:305 [inline]
> skb_release_data+0x1a3/0x880 net/core/skbuff.c:559
> skb_release_all+0x4a/0x60 net/core/skbuff.c:627
> __kfree_skb net/core/skbuff.c:641 [inline]
> kfree_skb+0x1bb/0x580 net/core/skbuff.c:659
> sit_tunnel_xmit+0x173/0x30d0 net/ipv6/sit.c:1044
> __netdev_start_xmit include/linux/netdevice.h:4328 [inline]
> netdev_start_xmit include/linux/netdevice.h:4337 [inline]
> xmit_one net/core/dev.c:3219 [inline]
> dev_hard_start_xmit+0x295/0xc90 net/core/dev.c:3235
> __dev_queue_xmit+0x2f0d/0x3950 net/core/dev.c:3805
> dev_queue_xmit+0x17/0x20 net/core/dev.c:3838
> packet_sendmsg_spkt+0xf44/0x16f0 net/packet/af_packet.c:1975
> sock_sendmsg_nosec net/socket.c:621 [inline]
> sock_sendmsg+0xd5/0x120 net/socket.c:631
> ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
> __sys_sendmsg+0x11d/0x280 net/socket.c:2154
> __do_sys_sendmsg net/socket.c:2163 [inline]
> __se_sys_sendmsg net/socket.c:2161 [inline]
> __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x457519
> Code: 1d b4 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 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007f2a52d30c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457519
> RDX: 0000000000000000 RSI: 00000000200003c0 RDI: 0000000000000003
> RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2a52d316d4
> R13: 00000000004c34d5 R14: 00000000004d52c8 R15: 00000000ffffffff
>
> Allocated by task 8395:
> save_stack+0x43/0xd0 mm/kasan/kasan.c:448
> set_track mm/kasan/kasan.c:460 [inline]
> kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
> __do_kmalloc_node mm/slab.c:3682 [inline]
> __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3696
> __kmalloc_reserve.isra.39+0x41/0xe0 net/core/skbuff.c:137
> __alloc_skb+0x155/0x770 net/core/skbuff.c:205
> alloc_skb include/linux/skbuff.h:997 [inline]
> sock_wmalloc+0x16d/0x1f0 net/core/sock.c:1934
> packet_sendmsg_spkt+0x48a/0x16f0 net/packet/af_packet.c:1922
> sock_sendmsg_nosec net/socket.c:621 [inline]
> sock_sendmsg+0xd5/0x120 net/socket.c:631
> ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
> __sys_sendmsg+0x11d/0x280 net/socket.c:2154
> __do_sys_sendmsg net/socket.c:2163 [inline]
> __se_sys_sendmsg net/socket.c:2161 [inline]
> __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> Freed by task 8395:
> save_stack+0x43/0xd0 mm/kasan/kasan.c:448
> set_track mm/kasan/kasan.c:460 [inline]
> __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
> kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
> __cache_free mm/slab.c:3498 [inline]
> kfree+0xcf/0x230 mm/slab.c:3813
> skb_free_head+0x99/0xc0 net/core/skbuff.c:550
> skb_release_data+0x6a4/0x880 net/core/skbuff.c:570
> skb_release_all+0x4a/0x60 net/core/skbuff.c:627
> __kfree_skb net/core/skbuff.c:641 [inline]
> consume_skb+0x1ae/0x570 net/core/skbuff.c:701
> packet_rcv+0x172/0x1820 net/packet/af_packet.c:2139
> dev_queue_xmit_nit+0x8ae/0xb30 net/core/dev.c:2020
> xmit_one net/core/dev.c:3215 [inline]
> dev_hard_start_xmit+0x186/0xc90 net/core/dev.c:3235
> __dev_queue_xmit+0x2f0d/0x3950 net/core/dev.c:3805
> dev_queue_xmit+0x17/0x20 net/core/dev.c:3838
> packet_sendmsg_spkt+0xf44/0x16f0 net/packet/af_packet.c:1975
> sock_sendmsg_nosec net/socket.c:621 [inline]
> sock_sendmsg+0xd5/0x120 net/socket.c:631
> ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
> __sys_sendmsg+0x11d/0x280 net/socket.c:2154
> __do_sys_sendmsg net/socket.c:2163 [inline]
> __se_sys_sendmsg net/socket.c:2161 [inline]
> __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> The buggy address belongs to the object at ffff8801d8cb4040
> which belongs to the cache kmalloc-512 of size 512
> The buggy address is located 224 bytes inside of
> 512-byte region [ffff8801d8cb4040, ffff8801d8cb4240)
> The buggy address belongs to the page:
> page:ffffea0007632d00 count:1 mapcount:0 mapping:ffff8801da800940
> index:0xffff8801d8cb42c0
> flags: 0x2fffc0000000100(slab)
> raw: 02fffc0000000100 ffffea00070baf08 ffffea000736a788 ffff8801da800940
> raw: ffff8801d8cb42c0 ffff8801d8cb4040 0000000100000005 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
> ffff8801d8cb4000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
> ffff8801d8cb4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>
> ffff8801d8cb4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>
> ^
> ffff8801d8cb4180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8801d8cb4200: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
> ==================================================================
>
>
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at [email protected].
>
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot.