WARNING in tcp_retransmit_timer

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: e2cd24b6 Linux 4.14.143
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11578e85600000
kernel config: https://syzkaller.appspot.com/x/.config?x=dcb6107bcdc0039
dashboard link: https://syzkaller.appspot.com/bug?extid=cfaf436d5e9137e46c0d
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+cfaf43...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at net/ipv4/tcp_timer.c:429
tcp_retransmit_timer+0x1ac5/0x2560 net/ipv4/tcp_timer.c:429
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.143 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x138/0x197 lib/dump_stack.c:53
panic+0x1f2/0x426 kernel/panic.c:182
__warn.cold+0x2f/0x36 kernel/panic.c:546
report_bug+0x216/0x254 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:177 [inline]
fixup_bug arch/x86/kernel/traps.c:172 [inline]
do_error_trap+0x1bb/0x310 arch/x86/kernel/traps.c:295
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963
RIP: 0010:tcp_retransmit_timer+0x1ac5/0x2560 net/ipv4/tcp_timer.c:429
RSP: 0018:ffff8880aee07c88 EFLAGS: 00010206
RAX: ffffffff87676240 RBX: ffff88806c8c4180 RCX: 0000000000000006
RDX: 0000000000000100 RSI: ffff8880621eb5cc RDI: ffff8880621eb798
RBP: ffff8880aee07ce8 R08: 0000002194655bde R09: ffff88821fff8008
R10: ffff88821fff8010 R11: 0000000000000001 R12: ffff8880621eadc0
R13: ffff8880621eb45a R14: ffff8880621eadf0 R15: 0000000000000000
tcp_write_timer_handler+0x479/0x7e0 net/ipv4/tcp_timer.c:579
tcp_write_timer+0xd8/0x180 net/ipv4/tcp_timer.c:597
call_timer_fn+0x161/0x670 kernel/time/timer.c:1279
expire_timers kernel/time/timer.c:1318 [inline]
__run_timers kernel/time/timer.c:1634 [inline]
__run_timers kernel/time/timer.c:1602 [inline]
run_timer_softirq+0x5b4/0x1570 kernel/time/timer.c:1647
__do_softirq+0x244/0x9a0 kernel/softirq.c:288
invoke_softirq kernel/softirq.c:368 [inline]
irq_exit+0x160/0x1b0 kernel/softirq.c:409
exiting_irq arch/x86/include/asm/apic.h:648 [inline]
smp_apic_timer_interrupt+0x146/0x5e0 arch/x86/kernel/apic/apic.c:1102
apic_timer_interrupt+0x96/0xa0 arch/x86/entry/entry_64.S:792
</IRQ>
RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
RSP: 0018:ffffffff87607de8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff10
RAX: 1ffffffff0ee2a84 RBX: ffffffff87676240 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffffffff87676abc
RBP: ffffffff87607e10 R08: 1ffffffff104a601 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff87715410
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff87676240
arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:557
default_idle_call+0x36/0x90 kernel/sched/idle.c:98
cpuidle_idle_call kernel/sched/idle.c:156 [inline]
do_idle+0x262/0x3d0 kernel/sched/idle.c:246
cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:351
rest_init+0x1d9/0x1e2 init/main.c:435
start_kernel+0x6df/0x6fd init/main.c:709
x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:381
x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:362
secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: e2cd24b6 Linux 4.14.143
git tree: linux-4.14.y

console output: https://syzkaller.appspot.com/x/log.txt?x=13f10185600000

kernel config: https://syzkaller.appspot.com/x/.config?x=dcb6107bcdc0039
dashboard link: https://syzkaller.appspot.com/bug?extid=cfaf436d5e9137e46c0d
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1491cd6e600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12888cf1600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+cfaf43...@syzkaller.appspotmail.com

IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready
IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready
8021q: adding VLAN 0 to HW filter on device batadv0
IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready

------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at net/ipv4/tcp_timer.c:429
tcp_retransmit_timer+0x1ac5/0x2560 net/ipv4/tcp_timer.c:429
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.143 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x138/0x197 lib/dump_stack.c:53
panic+0x1f2/0x426 kernel/panic.c:182
__warn.cold+0x2f/0x36 kernel/panic.c:546
report_bug+0x216/0x254 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:177 [inline]
fixup_bug arch/x86/kernel/traps.c:172 [inline]
do_error_trap+0x1bb/0x310 arch/x86/kernel/traps.c:295
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963
RIP: 0010:tcp_retransmit_timer+0x1ac5/0x2560 net/ipv4/tcp_timer.c:429
RSP: 0018:ffff8880aee07c88 EFLAGS: 00010206

RAX: ffffffff87676240 RBX: ffff88808d434040 RCX: 0000000000000006
RDX: 0000000000000100 RSI: ffff88808ae9a84c RDI: ffff88808ae9aa18
RBP: ffff8880aee07ce8 R08: 00000009e90eb22a R09: ffff88821fff8008
R10: ffff88821fff8010 R11: 0000000000000001 R12: ffff88808ae9a040
R13: ffff88808ae9a6da R14: ffff88808ae9a070 R15: 0000000000000000

[syzbot]

syzbot suspects this bug was fixed by commit:

commit ba2ddb43f270e6492ccce4fc42fc32c611de8f68
Author: Christoph Paasch <cpa...@apple.com>
Date: Fri Sep 13 20:08:19 2019 +0000

tcp: Don't dequeue SYN/FIN-segments from write-queue

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=110c3196e00000
start commit: e2cd24b6 Linux 4.14.143
git tree: linux-4.14.y

kernel config: https://syzkaller.appspot.com/x/.config?x=dcb6107bcdc0039
dashboard link: https://syzkaller.appspot.com/bug?extid=cfaf436d5e9137e46c0d

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1491cd6e600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12888cf1600000

If the result looks correct, please mark the bug fixed by replying with:

#syz fix: tcp: Don't dequeue SYN/FIN-segments from write-queue

For information about bisection process see: https://goo.gl/tpsmEJ#bisection