BUG: please report to dccp@xxxxxxxxxxxxxxx => prev = 2, last = 2 at net/dccp/ccids/lib/packet_history.c:LINE/tfrc_rx_his

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    ca9eb48fe01f Merge tag 'regulator-v5.0' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1482a939400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=963b24abf3f7c2d8
dashboard link: https://syzkaller.appspot.com/bug?extid=e786ba000564d103a6fe
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: syzbot+e786ba000564d103a6fe@xxxxxxxxxxxxxxxxxxxxxxxxx

input: syz0 as /devices/virtual/input/input6
BUG: please report to dccp@xxxxxxxxxxxxxxx => prev = 2, last = 2 at  
net/dccp/ccids/lib/packet_history.c:425/tfrc_rx_hist_sample_rtt()
CPU: 1 PID: 18 Comm: ksoftirqd/1 Not tainted 4.19.0+ #298
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+0x1c4/0x2b6 lib/dump_stack.c:113
 tfrc_rx_hist_sample_rtt.cold.3+0x54/0x5c  
net/dccp/ccids/lib/packet_history.c:422
 ccid3_hc_rx_packet_recv+0x5c4/0xeb0 net/dccp/ccids/ccid3.c:767
 ccid_hc_rx_packet_recv net/dccp/ccid.h:185 [inline]
 dccp_deliver_input_to_ccids+0xf0/0x280 net/dccp/input.c:180
 dccp_rcv_established+0x87/0xb0 net/dccp/input.c:378
 dccp_v4_do_rcv+0x153/0x180 net/dccp/ipv4.c:656
 sk_backlog_rcv include/net/sock.h:931 [inline]
 __sk_receive_skb+0x3e5/0xec0 net/core/sock.c:473
 dccp_v4_rcv+0x10f9/0x1f58 net/dccp/ipv4.c:877
 ip_local_deliver_finish+0x2e9/0xda0 net/ipv4/ip_input.c:215
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ip_local_deliver+0x1e9/0x750 net/ipv4/ip_input.c:256
 dst_input include/net/dst.h:450 [inline]
 ip_rcv_finish+0x1f9/0x300 net/ipv4/ip_input.c:415
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ip_rcv+0xed/0x600 net/ipv4/ip_input.c:524
 __netif_receive_skb_one_core+0x14d/0x200 net/core/dev.c:4913
 __netif_receive_skb+0x2c/0x1e0 net/core/dev.c:5023
 process_backlog+0x218/0x6f0 net/core/dev.c:5829
 napi_poll net/core/dev.c:6249 [inline]
 net_rx_action+0x7c5/0x1950 net/core/dev.c:6315
 __do_softirq+0x30c/0xb03 kernel/softirq.c:292
 run_ksoftirqd+0x94/0x100 kernel/softirq.c:653
 smpboot_thread_fn+0x68b/0xa00 kernel/smpboot.c:164
 kthread+0x35a/0x420 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413
net_ratelimit: 18 callbacks suppressed
dccp_close: ABORT with 105978 bytes unread
input: syz0 as /devices/virtual/input/input7
input: syz0 as /devices/virtual/input/input8
dccp_close: ABORT with 52730 bytes unread
input: syz0 as /devices/virtual/input/input9
dccp_close: ABORT with 105978 bytes unread
dccp_close: ABORT with 105978 bytes unread
dccp_close: ABORT with 77306 bytes unread
dccp_close: ABORT with 89594 bytes unread
input: syz0 as /devices/virtual/input/input10
input: syz0 as /devices/virtual/input/input11
input: syz0 as /devices/virtual/input/input12
input: syz0 as /devices/virtual/input/input13
input: syz0 as /devices/virtual/input/input14
input: syz0 as /devices/virtual/input/input15
input: syz0 as /devices/virtual/input/input16
input: syz0 as /devices/virtual/input/input17
input: syz0 as /devices/virtual/input/input18


---
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