syzbot

==================================================================
BUG: KMSAN: uninit-value in slab_alloc_node mm/slub.c:2703 [inline]
BUG: KMSAN: uninit-value in __kmalloc_node_track_caller+0x8da/0x1380 mm/slub.c:4351
CPU: 1 PID: 6372 Comm: syz-executor969 Not tainted 4.19.0-rc4+ #56
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+0x2f6/0x430 lib/dump_stack.c:113
 kmsan_report+0x183/0x2b0 mm/kmsan/kmsan.c:956
 __msan_warning+0x70/0xc0 mm/kmsan/kmsan_instr.c:645
 slab_alloc_node mm/slub.c:2703 [inline]
 __kmalloc_node_track_caller+0x8da/0x1380 mm/slub.c:4351
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x40d/0xe50 net/core/skbuff.c:206
 alloc_skb_fclone include/linux/skbuff.h:1038 [inline]
 sk_stream_alloc_skb+0x22a/0xe30 net/ipv4/tcp.c:874
 tcp_sendmsg_locked+0x2431/0x6a20 net/ipv4/tcp.c:1286
 tcp_sendmsg+0xb2/0x100 net/ipv4/tcp.c:1443
 inet_sendmsg+0x4c5/0x7d0 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 __sys_sendto+0x868/0xa30 net/socket.c:1786
 __do_sys_sendto net/socket.c:1798 [inline]
 __se_sys_sendto+0x107/0x130 net/socket.c:1794
 __x64_sys_sendto+0x6e/0x90 net/socket.c:1794
 do_syscall_64+0xb8/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x448889
Code: e8 fc e5 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 0b 01 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f19e5951da8 EFLAGS: 00000216 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000700028 RCX: 0000000000448889
RDX: fffffffffffffedd RSI: 0000000020000280 RDI: 0000000000000004
RBP: 0000000000700020 R08: 0000000020000080 R09: 000000000000001c
R10: 000000002000012c R11: 0000000000000216 R12: 000000000070002c
R13: 000000000080fc6f R14: 00007f19e59529c0 R15: 000000000000002d

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:181
 kmsan_kmalloc+0x98/0x100 mm/kmsan/kmsan_hooks.c:91
 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan_hooks.c:100
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2718 [inline]
 __kmalloc_node_track_caller+0xb55/0x1380 mm/slub.c:4351
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x40d/0xe50 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:996 [inline]
 __tcp_send_ack+0x10d/0x880 net/ipv4/tcp_output.c:3584
 tcp_send_ack+0x68/0x90 net/ipv4/tcp_output.c:3611
 tcp_delack_timer_handler+0x5f3/0xc00 net/ipv4/tcp_timer.c:301
 tcp_delack_timer+0x1a4/0x340 net/ipv4/tcp_timer.c:328
 call_timer_fn+0x310/0x6c0 kernel/time/timer.c:1326
 expire_timers kernel/time/timer.c:1363 [inline]
 __run_timers+0xe25/0x1280 kernel/time/timer.c:1682
 run_timer_softirq+0x2e/0x50 kernel/time/timer.c:1695
 __do_softirq+0x614/0xa72 kernel/softirq.c:292
==================================================================