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d47a721520
syzkaller was able to make the kernel reach subflow_data_ready() for a
server subflow that was closed before subflow_finish_connect() completed.
In these cases we can avoid using the path for regular/fallback MPTCP
data, and just wake the main socket, to avoid the following warning:
WARNING: CPU: 0 PID: 9370 at net/mptcp/subflow.c:885
subflow_data_ready+0x1e6/0x290 net/mptcp/subflow.c:885
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 9370 Comm: syz-executor.0 Not tainted 5.7.0 #106
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xb7/0xfe lib/dump_stack.c:118
panic+0x29e/0x692 kernel/panic.c:221
__warn.cold+0x2f/0x3d kernel/panic.c:582
report_bug+0x28b/0x2f0 lib/bug.c:195
fixup_bug arch/x86/kernel/traps.c:105 [inline]
fixup_bug arch/x86/kernel/traps.c:100 [inline]
do_error_trap+0x10f/0x180 arch/x86/kernel/traps.c:197
do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:216
invalid_op+0x1e/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:subflow_data_ready+0x1e6/0x290 net/mptcp/subflow.c:885
Code: 04 02 84 c0 74 06 0f 8e 91 00 00 00 41 0f b6 5e 48 31 ff 83 e3 18
89 de e8 37 ec 3d fe 84 db 0f 85 65 ff ff ff e8 fa ea 3d fe <0f> 0b e9
59 ff ff ff e8 ee ea 3d fe 48 89 ee 4c 89 ef e8 f3 77 ff
RSP: 0018:ffff88811b2099b0 EFLAGS: 00010206
RAX: ffff888111197000 RBX: 0000000000000000 RCX: ffffffff82fbc609
RDX: 0000000000000100 RSI: ffffffff82fbc616 RDI: 0000000000000001
RBP: ffff8881111bc800 R08: ffff888111197000 R09: ffffed10222a82af
R10: ffff888111541577 R11: ffffed10222a82ae R12: 1ffff11023641336
R13: ffff888111541000 R14: ffff88810fd4ca00 R15: ffff888111541570
tcp_child_process+0x754/0x920 net/ipv4/tcp_minisocks.c:841
tcp_v4_do_rcv+0x749/0x8b0 net/ipv4/tcp_ipv4.c:1642
tcp_v4_rcv+0x2666/0x2e60 net/ipv4/tcp_ipv4.c:1999
ip_protocol_deliver_rcu+0x29/0x1f0 net/ipv4/ip_input.c:204
ip_local_deliver_finish net/ipv4/ip_input.c:231 [inline]
NF_HOOK include/linux/netfilter.h:421 [inline]
ip_local_deliver+0x2da/0x390 net/ipv4/ip_input.c:252
dst_input include/net/dst.h:441 [inline]
ip_rcv_finish net/ipv4/ip_input.c:428 [inline]
ip_rcv_finish net/ipv4/ip_input.c:414 [inline]
NF_HOOK include/linux/netfilter.h:421 [inline]
ip_rcv+0xef/0x140 net/ipv4/ip_input.c:539
__netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:5268
__netif_receive_skb+0x27/0x1c0 net/core/dev.c:5382
process_backlog+0x1e5/0x6d0 net/core/dev.c:6226
napi_poll net/core/dev.c:6671 [inline]
net_rx_action+0x3e3/0xd70 net/core/dev.c:6739
__do_softirq+0x18c/0x634 kernel/softirq.c:292
do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1082
</IRQ>
do_softirq.part.0+0x26/0x30 kernel/softirq.c:337
do_softirq arch/x86/include/asm/preempt.h:26 [inline]
__local_bh_enable_ip+0x46/0x50 kernel/softirq.c:189
local_bh_enable include/linux/bottom_half.h:32 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:723 [inline]
ip_finish_output2+0x78a/0x19c0 net/ipv4/ip_output.c:229
__ip_finish_output+0x471/0x720 net/ipv4/ip_output.c:306
dst_output include/net/dst.h:435 [inline]
ip_local_out+0x181/0x1e0 net/ipv4/ip_output.c:125
__ip_queue_xmit+0x7a1/0x14e0 net/ipv4/ip_output.c:530
__tcp_transmit_skb+0x19dc/0x35e0 net/ipv4/tcp_output.c:1238
__tcp_send_ack.part.0+0x3c2/0x5b0 net/ipv4/tcp_output.c:3785
__tcp_send_ack net/ipv4/tcp_output.c:3791 [inline]
tcp_send_ack+0x7d/0xa0 net/ipv4/tcp_output.c:3791
tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6040 [inline]
tcp_rcv_state_process+0x36a4/0x49c2 net/ipv4/tcp_input.c:6209
tcp_v4_do_rcv+0x343/0x8b0 net/ipv4/tcp_ipv4.c:1651
sk_backlog_rcv include/net/sock.h:996 [inline]
__release_sock+0x1ad/0x310 net/core/sock.c:2548
release_sock+0x54/0x1a0 net/core/sock.c:3064
inet_wait_for_connect net/ipv4/af_inet.c:594 [inline]
__inet_stream_connect+0x57e/0xd50 net/ipv4/af_inet.c:686
inet_stream_connect+0x53/0xa0 net/ipv4/af_inet.c:725
mptcp_stream_connect+0x171/0x5f0 net/mptcp/protocol.c:1920
__sys_connect_file net/socket.c:1854 [inline]
__sys_connect+0x267/0x2f0 net/socket.c:1871
__do_sys_connect net/socket.c:1882 [inline]
__se_sys_connect net/socket.c:1879 [inline]
__x64_sys_connect+0x6f/0xb0 net/socket.c:1879
do_syscall_64+0xb7/0x3d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fb577d06469
Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 8b 0d ff 49 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007fb5783d5dd8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 000000000068bfa0 RCX: 00007fb577d06469
RDX: 000000000000004d RSI: 0000000020000040 RDI: 0000000000000003
RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000041427c R14: 00007fb5783d65c0 R15: 0000000000000003
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/39
Reported-by: Christoph Paasch <cpaasch@apple.com>
Fixes: e1ff9e82e2 ("net: mptcp: improve fallback to TCP")
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.