syzbot

FS-Cache: O-cookie c=000000003e6afeea [p=000000003e396173 fl=222 nc=0 na=1]
FS-Cache: O-cookie d=000000000f8903e4 n=00000000ad08757b
FS-Cache: O-key=[16] '0200000000000000020000807f000008'
FS-Cache: N-cookie c=000000007c6f8fe7 [p=000000003e396173 fl=2 nc=0 na=1]
FS-Cache: N-cookie d=000000000f8903e4 n=000000005098b971
FS-Cache: N-key=[16] '0200000000000000020000807f000008'
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BUG: KCSAN: data-race in xprt_connect / xprt_unlock_connect

write to 0xffff88802d7de4c0 of 8 bytes by task 2040 on cpu 0:
 xprt_unlock_connect+0x7b/0x150 net/sunrpc/xprt.c:881
 xs_udp_setup_socket+0x347/0x410 net/sunrpc/xprtsock.c:2060
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275
 worker_thread+0x635/0xb90 kernel/workqueue.c:2421
 kthread+0x1fd/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff88802d7de4c0 of 8 bytes by task 6547 on cpu 1:
 xprt_release_write net/sunrpc/xprt.c:447 [inline]
 xprt_connect+0x2ec/0x4d0 net/sunrpc/xprt.c:931
 call_connect+0x105/0x150 net/sunrpc/clnt.c:2053
 __rpc_execute+0x11c/0x950 net/sunrpc/sched.c:891
 rpc_execute+0xc5/0x140 net/sunrpc/sched.c:967
 rpc_run_task+0x375/0x390 net/sunrpc/clnt.c:1140
 rpc_call_sync net/sunrpc/clnt.c:1169 [inline]
 rpc_ping net/sunrpc/clnt.c:2682 [inline]
 rpc_create_xprt+0x1c3/0x410 net/sunrpc/clnt.c:477
 rpc_create+0x346/0x430 net/sunrpc/clnt.c:593
 nfs_create_rpc_client+0x2a8/0x330 fs/nfs/client.c:536
 nfs_init_client+0x3d/0xa0 fs/nfs/client.c:653
 nfs_get_client+0x869/0x940 fs/nfs/client.c:430
 nfs_init_server fs/nfs/client.c:692 [inline]
 nfs_create_server+0x455/0xff0 fs/nfs/client.c:996
 nfs_try_get_tree+0x19d/0x6c0 fs/nfs/super.c:939
 nfs_get_tree+0xa48/0xa70 fs/nfs/fs_context.c:1350
 vfs_get_tree+0x4a/0x190 fs/super.c:1496
 do_new_mount fs/namespace.c:2878 [inline]
 path_mount+0x119d/0x1c10 fs/namespace.c:3208
 do_mount fs/namespace.c:3221 [inline]
 __do_sys_mount fs/namespace.c:3429 [inline]
 __se_sys_mount+0x23d/0x2e0 fs/namespace.c:3406
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3406
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 6547 Comm: syz-executor.2 Not tainted 5.11.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================