sysbox-fs enter deallock

[okhowang]

I use sysbox with docker on centos-liked linux.
kernel version 6.6
sysbox version 0.6.7 ( I use package from https://github.com/karellen/karellen-sysbox )
docker version 28.4.0

sometimes sysbox-fs become unresponsable.

I found request to sysbox-fs was stucked on css.Lock()
and one ContainerPreRegister goroutine stucked on srv.InitWait() in CreateFuseServer
but all goroutines created by CreateFuseServer were waiting on fuse.(*Conn).ReadRequest

I notice that fuseServer.Run may return directly, left s.initDone untouched.
it may failed at fuse.Mount, but I can't pick out the log from here
sysbox-fs's log may like

time="2025-12-30 10:55:21" level=info msg="Container pre-registration completed: id = f94491638433"
time="2025-12-30 10:55:21" level=info msg="Container registration completed: id = 8338ff2129b4, initPid = 1531739, uid:gid = 100000:100000"
time="2025-12-30 10:55:21" level=info msg="Container unregistration completed: id = 82d627f3d5a9"
time="2025-12-30 10:55:21" level=info msg="Container registration completed: id = f94491638433, initPid = 1531787, uid:gid = 100000:100000"
time="2025-12-30 10:55:21" level=info msg="Container pre-registration completed: id = 1fb490132bd6"
time="2025-12-30 10:55:21" level=info msg="Container registration completed: id = 1fb490132bd6, initPid = 1532300, uid:gid = 100000:100000"
time="2025-12-30 10:55:21" level=info msg="Container unregistration completed: id = 8338ff2129b4"
time="2025-12-30 10:55:21" level=info msg="Container unregistration completed: id = f94491638433"
time="2025-12-30 10:55:22" level=info msg="Container unregistration completed: id = 1fb490132bd6"
time="2025-12-30 10:55:22" level=info msg="Container pre-registration completed: id = c14fe60b247c"
time="2025-12-30 10:55:22" level=info msg="Container registration completed: id = c14fe60b247c, initPid = 1533088, uid:gid = 100000:100000"
time="2025-12-30 10:55:22" level=info msg="Container unregistration completed: id = a067c8a45c4a"
time="2025-12-30 10:55:23" level=info msg="Container unregistration completed: id = e95e41ad806b"
time="2025-12-30 10:55:23" level=info msg="Container unregistration completed: id = c14fe60b247c"
time="2025-12-30 10:55:24" level=info msg="Container pre-registration completed: id = e02075b10cfc"
time="2025-12-30 10:55:24" level=info msg="Container unregistration completed: id = ec7307f20f10"
time="2025-12-30 10:55:24" level=info msg="Container registration completed: id = e02075b10cfc, initPid = 1534324, uid:gid = 100000:100000"
time="2025-12-30 10:55:25" level=info msg="Container unregistration completed: id = e35979d7acbb"
time="2025-12-30 10:55:25" level=info msg="Container pre-registration completed: id = 782ff1a076b2"
time="2025-12-30 10:55:26" level=info msg="Container registration completed: id = 782ff1a076b2, initPid = 1536552, uid:gid = 100000:100000"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1536924"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1536931"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1536934"
time="2025-12-30 10:55:26" level=info msg="Container pre-registration completed: id = 53d32a403562"
time="2025-12-30 10:55:26" level=info msg="Container unregistration completed: id = 782ff1a076b2"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537014"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537016"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537018"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537020"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537025"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537131"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537134"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537136"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537140"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537148"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537154"
time="2025-12-30 10:55:26" level=info msg="Container registration completed: id = 53d32a403562, initPid = 1537084, uid:gid = 100000:100000"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537242"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537256"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537263"
time="2025-12-30 10:55:26" level=warning msg="Sysbox-fs first child process error status: exit status 1, pid: 1537266"

dlv core output with grs -group userloc

github.com/nestybox/sysbox-fs/fuse/server.go:213 in github.com/nestybox/sysbox-fs/fuse.(*FuseServerService).CreateFuseServer
          Goroutine 3640530 - User: github.com/nestybox/sysbox-fs/fuse/server.go:213 github.com/nestybox/sysbox-fs/fuse.(*FuseServerService).CreateFuseServer (0x5fd685) [unknown wait reason 14 516748745301316]
        Total: 1

internal/sync/mutex.go:70 in sync.(*RWMutex).Lock
          Goroutine 3645228 - User: internal/sync/mutex.go:70 sync.(*RWMutex).Lock (0x49f932) [unknown wait reason 22 516767446953500]
          Goroutine 3673629 - User: internal/sync/mutex.go:70 sync.(*RWMutex).Lock (0x49f932) [unknown wait reason 22 516956251790091]
          Goroutine 3642287 - User: internal/sync/mutex.go:70 sync.(*RWMutex).Lock (0x49f932) [unknown wait reason 22 516748745301316]
          Goroutine 3698300 - User: internal/sync/mutex.go:70 sync.(*RWMutex).Lock (0x49f932) [unknown wait reason 22 517145373088660]
          Goroutine 3656936 - User: internal/sync/mutex.go:70 sync.(*RWMutex).Lock (0x49f932) [unknown wait reason 22 516819640709316]
        Total: 23

I found a log

time="2025-12-30 10:55:35" level=error msg="fusermount: waitid: no child processes"