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BUG: KASAN: use-after-free in ccid2_hc_tx_packet_recv+0x21ca/0x223b net/dccp/ccids/ccid2.c:600
Read of size 1 at addr ffff8880619704e2 by task syz-executor.4/28574

CPU: 0 PID: 28574 Comm: syz-executor.4 Not tainted 5.1.0-rc6+ #158
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
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:129
 ccid2_hc_tx_packet_recv+0x21ca/0x223b net/dccp/ccids/ccid2.c:600
 ccid_hc_tx_packet_recv net/dccp/ccid.h:192 [inline]
 dccp_deliver_input_to_ccids+0x202/0x280 net/dccp/input.c:186
 dccp_rcv_established net/dccp/input.c:378 [inline]
 dccp_rcv_established+0x83/0xb0 net/dccp/input.c:368
 dccp_v4_do_rcv+0x139/0x190 net/dccp/ipv4.c:659
 sk_backlog_rcv include/net/sock.h:945 [inline]
 __release_sock+0x12e/0x3a0 net/core/sock.c:2413
 release_sock+0x59/0x1c0 net/core/sock.c:2929
 dccp_sendmsg+0x683/0xd00 net/dccp/proto.c:818
 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_sendmsg+0x3e2/0x930 net/socket.c:2280
 __sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2375
 __do_sys_sendmmsg net/socket.c:2404 [inline]
 __se_sys_sendmmsg net/socket.c:2401 [inline]
 __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2401
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458da9
Code: ad b8 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 b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f60da33bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f60da33bc90 RCX: 0000000000458da9
RDX: 04000000000001e6 RSI: 0000000020000c00 RDI: 0000000000000005
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f60da33c6d4
R13: 00000000004c5fac R14: 00000000004da760 R15: 0000000000000006

Allocated by task 28574:
 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:3687 [inline]
 __kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3701
 __kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:142
 __alloc_skb+0x10b/0x5e0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1058 [inline]
 dccp_send_ack+0xd6/0x360 net/dccp/output.c:580
 ccid2_hc_rx_packet_recv+0x139/0x1b0 net/dccp/ccids/ccid2.c:779
 ccid_hc_rx_packet_recv net/dccp/ccid.h:185 [inline]
 dccp_deliver_input_to_ccids+0xee/0x280 net/dccp/input.c:180
 dccp_rcv_established net/dccp/input.c:378 [inline]
 dccp_rcv_established+0x83/0xb0 net/dccp/input.c:368
 dccp_v4_do_rcv+0x139/0x190 net/dccp/ipv4.c:659
 sk_backlog_rcv include/net/sock.h:945 [inline]
 __sk_receive_skb+0x33a/0xbe0 net/core/sock.c:527
 dccp_v4_rcv+0xeaa/0x1bf1 net/dccp/ipv4.c:880
 ip_protocol_deliver_rcu+0x60/0x8f0 net/ipv4/ip_input.c:208
 ip_local_deliver_finish+0x23b/0x390 net/ipv4/ip_input.c:234
 NF_HOOK include/linux/netfilter.h:296 [inline]
 NF_HOOK include/linux/netfilter.h:290 [inline]
 ip_local_deliver+0x1e9/0x520 net/ipv4/ip_input.c:255
 dst_input include/net/dst.h:439 [inline]
 ip_rcv_finish+0x1e1/0x300 net/ipv4/ip_input.c:413
 NF_HOOK include/linux/netfilter.h:296 [inline]
 NF_HOOK include/linux/netfilter.h:290 [inline]
 ip_rcv+0xe8/0x3f0 net/ipv4/ip_input.c:523
 __netif_receive_skb_one_core+0x115/0x1a0 net/core/dev.c:4990
 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5102
 process_backlog+0x206/0x750 net/core/dev.c:5942
 napi_poll net/core/dev.c:6365 [inline]
 net_rx_action+0x4fa/0x1070 net/core/dev.c:6431
 __do_softirq+0x266/0x95a kernel/softirq.c:293

Freed by task 28574:
 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:3499 [inline]
 kfree+0xcf/0x230 mm/slab.c:3822
 skb_free_head+0x93/0xb0 net/core/skbuff.c:592
 skb_release_data+0x576/0x7a0 net/core/skbuff.c:612
 skb_release_all+0x4d/0x60 net/core/skbuff.c:666
 __kfree_skb net/core/skbuff.c:680 [inline]
 kfree_skb net/core/skbuff.c:698 [inline]
 kfree_skb+0xe8/0x390 net/core/skbuff.c:692
 dccp_v4_do_rcv net/dccp/ipv4.c:694 [inline]
 dccp_v4_do_rcv+0x160/0x190 net/dccp/ipv4.c:654
 sk_backlog_rcv include/net/sock.h:945 [inline]
 __release_sock+0x12e/0x3a0 net/core/sock.c:2413
 release_sock+0x59/0x1c0 net/core/sock.c:2929
 dccp_sendmsg+0x683/0xd00 net/dccp/proto.c:818
 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_sendmsg+0x3e2/0x930 net/socket.c:2280
 __sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2375
 __do_sys_sendmmsg net/socket.c:2404 [inline]
 __se_sys_sendmmsg net/socket.c:2401 [inline]
 __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2401
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff888061970040
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1186 bytes inside of
 2048-byte region [ffff888061970040, ffff888061970840)
The buggy address belongs to the page:
page:ffffea0001865c00 count:1 mapcount:0 mapping:ffff88812c3f0c40 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00018bf708 ffffea0001894388 ffff88812c3f0c40
raw: 0000000000000000 ffff888061970040 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888061970380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888061970400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888061970480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff888061970500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888061970580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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