syzbot

==================================================================
BUG: KCSAN: data-race in kcm_rcv_strparser / kcm_rfree

write to 0xffff8881238447c0 of 1 bytes by task 46 on cpu 1:
 reserve_rx_kcm net/kcm/kcmsock.c:283 [inline]
 kcm_rcv_strparser+0x250/0x3a0 net/kcm/kcmsock.c:363
 __strp_recv+0x64c/0xd20 net/strparser/strparser.c:301
 strp_recv+0x6d/0x80 net/strparser/strparser.c:335
 tcp_read_sock+0x13e/0x5a0 net/ipv4/tcp.c:1704
 strp_read_sock net/strparser/strparser.c:358 [inline]
 do_strp_work net/strparser/strparser.c:406 [inline]
 strp_work+0xe8/0x180 net/strparser/strparser.c:415
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

read to 0xffff8881238447c0 of 1 bytes by task 2660 on cpu 0:
 kcm_rfree+0x121/0x220 net/kcm/kcmsock.c:181
 skb_release_head_state+0x8e/0x160 net/core/skbuff.c:739
 skb_release_all net/core/skbuff.c:750 [inline]
 __kfree_skb+0x14/0x150 net/core/skbuff.c:766
 kfree_skb_reason+0x52/0x170 net/core/skbuff.c:788
 kfree_skb include/linux/skbuff.h:1206 [inline]
 kcm_recvmsg+0x226/0x2b0 net/kcm/kcmsock.c:1161
 ____sys_recvmsg+0x162/0x2f0
 ___sys_recvmsg net/socket.c:2743 [inline]
 do_recvmmsg+0x2f1/0x710 net/socket.c:2837
 __sys_recvmmsg net/socket.c:2916 [inline]
 __do_sys_recvmmsg net/socket.c:2939 [inline]
 __se_sys_recvmmsg net/socket.c:2932 [inline]
 __x64_sys_recvmmsg+0xde/0x160 net/socket.c:2932
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2660 Comm: syz-executor.4 Not tainted 6.0.0-rc2-syzkaller-00327-g8379c0b31fbc-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
==================================================================