4.20-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit bf50b606cfd85ac8d3d0adb711f3e22204059848 ]
syzbot reported a WARN_ON(!tcp_skb_pcount(skb)) in tcp_send_loss_probe() [1]
This was caused by TCP_REPAIR sent skbs that inadvertenly were missing a call to tcp_init_tso_segs()
[1] WARNING: CPU: 1 PID: 0 at net/ipv4/tcp_output.c:2534 tcp_send_loss_probe+0x771/0x8a0 net/ipv4/tcp_output.c:2534 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.0.0-rc7+ #77 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 panic+0x2cb/0x65c kernel/panic.c:214 __warn.cold+0x20/0x45 kernel/panic.c:571 report_bug+0x263/0x2b0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 RIP: 0010:tcp_send_loss_probe+0x771/0x8a0 net/ipv4/tcp_output.c:2534 Code: 88 fc ff ff 4c 89 ef e8 ed 75 c8 fb e9 c8 fc ff ff e8 43 76 c8 fb e9 63 fd ff ff e8 d9 75 c8 fb e9 94 f9 ff ff e8 bf 03 91 fb <0f> 0b e9 7d fa ff ff e8 b3 03 91 fb 0f b6 1d 37 43 7a 03 31 ff 89 RSP: 0018:ffff8880ae907c60 EFLAGS: 00010206 RAX: ffff8880a989c340 RBX: 0000000000000000 RCX: ffffffff85dedbdb RDX: 0000000000000100 RSI: ffffffff85dee0b1 RDI: 0000000000000005 RBP: ffff8880ae907c90 R08: ffff8880a989c340 R09: ffffed10147d1ae1 R10: ffffed10147d1ae0 R11: ffff8880a3e8d703 R12: ffff888091b90040 R13: ffff8880a3e8d540 R14: 0000000000008000 R15: ffff888091b90860 tcp_write_timer_handler+0x5c0/0x8a0 net/ipv4/tcp_timer.c:583 tcp_write_timer+0x10e/0x1d0 net/ipv4/tcp_timer.c:607 call_timer_fn+0x190/0x720 kernel/time/timer.c:1325 expire_timers kernel/time/timer.c:1362 [inline] __run_timers kernel/time/timer.c:1681 [inline] __run_timers kernel/time/timer.c:1649 [inline] run_timer_softirq+0x652/0x1700 kernel/time/timer.c:1694 __do_softirq+0x266/0x95a kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 </IRQ> RIP: 0010:native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:58 Code: ff ff ff 48 89 c7 48 89 45 d8 e8 59 0c a1 fa 48 8b 45 d8 e9 ce fe ff ff 48 89 df e8 48 0c a1 fa eb 82 90 90 90 90 90 90 fb f4 <c3> 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f4 c3 90 90 90 90 90 90 RSP: 0018:ffff8880a98afd78 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff1125061 RBX: ffff8880a989c340 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880a989cbbc RBP: ffff8880a98afda8 R08: ffff8880a989c340 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffffffff889282f8 R14: 0000000000000001 R15: 0000000000000000 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:555 default_idle_call+0x36/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x386/0x570 kernel/sched/idle.c:262 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:353 start_secondary+0x404/0x5c0 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 Kernel Offset: disabled Rebooting in 86400 seconds..
Fixes: 79861919b889 ("tcp: fix TCP_REPAIR xmit queue setup") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Cc: Andrey Vagin avagin@openvz.org Cc: Soheil Hassas Yeganeh soheil@google.com Cc: Neal Cardwell ncardwell@google.com Acked-by: Soheil Hassas Yeganeh soheil@google.com Acked-by: Neal Cardwell ncardwell@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/tcp_output.c | 1 + 1 file changed, 1 insertion(+)
--- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2341,6 +2341,7 @@ static bool tcp_write_xmit(struct sock * /* "skb_mstamp_ns" is used as a start point for the retransmit timer */ skb->skb_mstamp_ns = tp->tcp_wstamp_ns = tp->tcp_clock_cache; list_move_tail(&skb->tcp_tsorted_anchor, &tp->tsorted_sent_queue); + tcp_init_tso_segs(skb, mss_now); goto repair; /* Skip network transmission */ }