KCSAN: data-race in xprt_connect / xprt_unlock_connect (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 09162bc3 Linux 5.10-rc4
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13fbe726500000
kernel config: https://syzkaller.appspot.com/x/.config?x=e0bbcd06922dbd46
dashboard link: https://syzkaller.appspot.com/bug?extid=667f4e94ef31c270a278
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [anna.sc...@netapp.com bfi...@fieldses.org chuck...@oracle.com da...@davemloft.net ku...@kernel.org linux-...@vger.kernel.org linu...@vger.kernel.org net...@vger.kernel.org trond.m...@hammerspace.com]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+667f4e...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in xprt_connect / xprt_unlock_connect

write to 0xffff8880259ffcc0 of 8 bytes by task 8485 on cpu 1:
xprt_unlock_connect+0x7b/0x150 net/sunrpc/xprt.c:820
xs_udp_setup_socket+0x347/0x410 net/sunrpc/xprtsock.c:2059
process_one_work+0x3e1/0x950 kernel/workqueue.c:2272
worker_thread+0x635/0xb90 kernel/workqueue.c:2418
kthread+0x1fa/0x220 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff8880259ffcc0 of 8 bytes by task 10641 on cpu 0:
xprt_release_write net/sunrpc/xprt.c:386 [inline]
xprt_connect+0x2ec/0x4d0 net/sunrpc/xprt.c:870
call_connect+0x105/0x150 net/sunrpc/clnt.c:2056
__rpc_execute+0x11c/0x950 net/sunrpc/sched.c:886
rpc_execute+0xc5/0x140 net/sunrpc/sched.c:962
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:2685 [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+0x44b/0xfe0 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:1347
vfs_get_tree+0x4a/0x190 fs/super.c:1549
do_new_mount fs/namespace.c:2875 [inline]
path_mount+0x119d/0x1c10 fs/namespace.c:3205
do_mount fs/namespace.c:3218 [inline]
__do_sys_mount fs/namespace.c:3426 [inline]
__se_sys_mount+0x23d/0x2e0 fs/namespace.c:3403
__x64_sys_mount+0x63/0x70 fs/namespace.c:3403
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: 0 PID: 10641 Comm: syz-executor.4 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.