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KMSAN caught uninit-value in tcp_create_openreq_child() [1]
This is caused by a recent change, combined by the fact
that TCP cleared num_timeout, num_retrans and sk fields only
when a request socket was about to be queued.
Under syncookie mode, a temporary request socket is used,
and req->num_timeout could contain garbage.
Lets clear these three fields sooner, there is really no
point trying to defer this and risk other bugs.
[1]
BUG: KMSAN: uninit-value in tcp_create_openreq_child+0x157f/0x1cc0 net/ipv4/tcp_minisocks.c:526
CPU: 1 PID: 13357 Comm: syz-executor591 Not tainted 5.2.0-rc4+ #3
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+0x191/0x1f0 lib/dump_stack.c:113
kmsan_report+0x162/0x2d0 mm/kmsan/kmsan.c:611
__msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:304
tcp_create_openreq_child+0x157f/0x1cc0 net/ipv4/tcp_minisocks.c:526
tcp_v6_syn_recv_sock+0x761/0x2d80 net/ipv6/tcp_ipv6.c:1152
tcp_get_cookie_sock+0x16e/0x6b0 net/ipv4/syncookies.c:209
cookie_v6_check+0x27e0/0x29a0 net/ipv6/syncookies.c:252
tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1039 [inline]
tcp_v6_do_rcv+0xf1c/0x1ce0 net/ipv6/tcp_ipv6.c:1344
tcp_v6_rcv+0x60b7/0x6a30 net/ipv6/tcp_ipv6.c:1554
ip6_protocol_deliver_rcu+0x1433/0x22f0 net/ipv6/ip6_input.c:397
ip6_input_finish net/ipv6/ip6_input.c:438 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ip6_input+0x2af/0x340 net/ipv6/ip6_input.c:447
dst_input include/net/dst.h:439 [inline]
ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ipv6_rcv+0x683/0x710 net/ipv6/ip6_input.c:272
__netif_receive_skb_one_core net/core/dev.c:4981 [inline]
__netif_receive_skb net/core/dev.c:5095 [inline]
process_backlog+0x721/0x1410 net/core/dev.c:5906
napi_poll net/core/dev.c:6329 [inline]
net_rx_action+0x738/0x1940 net/core/dev.c:6395
__do_softirq+0x4ad/0x858 kernel/softirq.c:293
do_softirq_own_stack+0x49/0x80 arch/x86/entry/entry_64.S:1052
</IRQ>
do_softirq kernel/softirq.c:338 [inline]
__local_bh_enable_ip+0x199/0x1e0 kernel/softirq.c:190
local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
rcu_read_unlock_bh include/linux/rcupdate.h:682 [inline]
ip6_finish_output2+0x213f/0x2670 net/ipv6/ip6_output.c:117
ip6_finish_output+0xae4/0xbc0 net/ipv6/ip6_output.c:150
NF_HOOK_COND include/linux/netfilter.h:294 [inline]
ip6_output+0x5d3/0x720 net/ipv6/ip6_output.c:167
dst_output include/net/dst.h:433 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ip6_xmit+0x1f53/0x2650 net/ipv6/ip6_output.c:271
inet6_csk_xmit+0x3df/0x4f0 net/ipv6/inet6_connection_sock.c:135
__tcp_transmit_skb+0x4076/0x5b40 net/ipv4/tcp_output.c:1156
tcp_transmit_skb net/ipv4/tcp_output.c:1172 [inline]
tcp_write_xmit+0x39a9/0xa730 net/ipv4/tcp_output.c:2397
__tcp_push_pending_frames+0x124/0x4e0 net/ipv4/tcp_output.c:2573
tcp_send_fin+0xd43/0x1540 net/ipv4/tcp_output.c:3118
tcp_close+0x16ba/0x1860 net/ipv4/tcp.c:2403
inet_release+0x1f7/0x270 net/ipv4/af_inet.c:427
inet6_release+0xaf/0x100 net/ipv6/af_inet6.c:470
__sock_release net/socket.c:601 [inline]
sock_close+0x156/0x490 net/socket.c:1273
__fput+0x4c9/0xba0 fs/file_table.c:280
____fput+0x37/0x40 fs/file_table.c:313
task_work_run+0x22e/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:185 [inline]
exit_to_usermode_loop arch/x86/entry/common.c:168 [inline]
prepare_exit_to_usermode+0x39d/0x4d0 arch/x86/entry/common.c:199
syscall_return_slowpath+0x90/0x5c0 arch/x86/entry/common.c:279
do_syscall_64+0xe2/0xf0 arch/x86/entry/common.c:305
entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x401d50
Code: 01 f0 ff ff 0f 83 40 0d 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 83 3d dd 8d 2d 00 00 75 14 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 14 0d 00 00 c3 48 83 ec 08 e8 7a 02 00 00
RSP: 002b:00007fff1cf58cf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000401d50
RDX: 000000000000001c RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00000000004a9050 R08: 0000000020000040 R09: 000000000000001c
R10: 0000000020004004 R11: 0000000000000246 R12: 0000000000402ef0
R13: 0000000000402f80 R14: 0000000000000000 R15: 0000000000000000
Uninit was created at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:201 [inline]
kmsan_internal_poison_shadow+0x53/0xa0 mm/kmsan/kmsan.c:160
kmsan_kmalloc+0xa4/0x130 mm/kmsan/kmsan_hooks.c:177
kmem_cache_alloc+0x534/0xb00 mm/slub.c:2781
reqsk_alloc include/net/request_sock.h:84 [inline]
inet_reqsk_alloc+0xa8/0x600 net/ipv4/tcp_input.c:6384
cookie_v6_check+0xadb/0x29a0 net/ipv6/syncookies.c:173
tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1039 [inline]
tcp_v6_do_rcv+0xf1c/0x1ce0 net/ipv6/tcp_ipv6.c:1344
tcp_v6_rcv+0x60b7/0x6a30 net/ipv6/tcp_ipv6.c:1554
ip6_protocol_deliver_rcu+0x1433/0x22f0 net/ipv6/ip6_input.c:397
ip6_input_finish net/ipv6/ip6_input.c:438 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ip6_input+0x2af/0x340 net/ipv6/ip6_input.c:447
dst_input include/net/dst.h:439 [inline]
ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ipv6_rcv+0x683/0x710 net/ipv6/ip6_input.c:272
__netif_receive_skb_one_core net/core/dev.c:4981 [inline]
__netif_receive_skb net/core/dev.c:5095 [inline]
process_backlog+0x721/0x1410 net/core/dev.c:5906
napi_poll net/core/dev.c:6329 [inline]
net_rx_action+0x738/0x1940 net/core/dev.c:6395
__do_softirq+0x4ad/0x858 kernel/softirq.c:293
do_softirq_own_stack+0x49/0x80 arch/x86/entry/entry_64.S:1052
do_softirq kernel/softirq.c:338 [inline]
__local_bh_enable_ip+0x199/0x1e0 kernel/softirq.c:190
local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
rcu_read_unlock_bh include/linux/rcupdate.h:682 [inline]
ip6_finish_output2+0x213f/0x2670 net/ipv6/ip6_output.c:117
ip6_finish_output+0xae4/0xbc0 net/ipv6/ip6_output.c:150
NF_HOOK_COND include/linux/netfilter.h:294 [inline]
ip6_output+0x5d3/0x720 net/ipv6/ip6_output.c:167
dst_output include/net/dst.h:433 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ip6_xmit+0x1f53/0x2650 net/ipv6/ip6_output.c:271
inet6_csk_xmit+0x3df/0x4f0 net/ipv6/inet6_connection_sock.c:135
__tcp_transmit_skb+0x4076/0x5b40 net/ipv4/tcp_output.c:1156
tcp_transmit_skb net/ipv4/tcp_output.c:1172 [inline]
tcp_write_xmit+0x39a9/0xa730 net/ipv4/tcp_output.c:2397
__tcp_push_pending_frames+0x124/0x4e0 net/ipv4/tcp_output.c:2573
tcp_send_fin+0xd43/0x1540 net/ipv4/tcp_output.c:3118
tcp_close+0x16ba/0x1860 net/ipv4/tcp.c:2403
inet_release+0x1f7/0x270 net/ipv4/af_inet.c:427
inet6_release+0xaf/0x100 net/ipv6/af_inet6.c:470
__sock_release net/socket.c:601 [inline]
sock_close+0x156/0x490 net/socket.c:1273
__fput+0x4c9/0xba0 fs/file_table.c:280
____fput+0x37/0x40 fs/file_table.c:313
task_work_run+0x22e/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:185 [inline]
exit_to_usermode_loop arch/x86/entry/common.c:168 [inline]
prepare_exit_to_usermode+0x39d/0x4d0 arch/x86/entry/common.c:199
syscall_return_slowpath+0x90/0x5c0 arch/x86/entry/common.c:279
do_syscall_64+0xe2/0xf0 arch/x86/entry/common.c:305
entry_SYSCALL_64_after_hwframe+0x63/0xe7
Fixes: 336c39a031 ("tcp: undo init congestion window on false SYNACK timeout")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Yuchung Cheng <ycheng@google.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.