https://bugs.kde.org/show_bug.cgi?id=525137
Bug ID: 525137
Summary: kio-fuse causes system freeze and fails suspend due to
task hanging in uninterruptible sleep (state:D) on
FUSE request timeout
Classification: Applications
Product: kdeconnect
Version First 26.08.0
Reported In:
Platform: Other
OS: Linux
Status: REPORTED
Severity: critical
Priority: NOR
Component: desktop-application
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
When the system attempts to enter sleep/suspend, the process freezing stage
fails and hangs indefinitely (for 20+ seconds) because a task interacting with
a kio-fuse mount point gets stuck in uninterruptible sleep (state:D) waiting
for a FUSE answer (request_wait_answer) that never arrives. This prevents the
kernel from completing the suspend sequence, forcing the system to abort/resume
or lock up.
Environment:
Desktop Environment: KDE Plasma
VFS / Mount involved: kio-fuse (e.g., /run/user/1000/kio-fuse-*)
Kernel Logs (dmesg):
[ 5333.758886] Freezing user space processes
[ 5353.765051] Freezing user space processes failed after 20.006 seconds (1
tasks refusing to freeze, wq_busy=0):
[ 5353.765193] task:lsof state:D stack:0 pid:57142 tgid:57142
ppid:57141 task_flags:0x400040 flags:0x00080002
[ 5353.765199] Call Trace:
[ 5353.765202] <TASK>
[ 5353.765206] __schedule+0x402/0x1700
[ 5353.765216] ? __wake_up+0xb9/0xf0
[ 5353.765224] schedule+0x27/0xa0
[ 5353.765226] request_wait_answer+0xe2/0x300
[ 5353.765233] ? __pfx_autoremove_wake_function+0x10/0x10
[ 5353.765236] fuse_chan_send+0x1e0/0x350
[ 5353.765239] fuse_do_getattr+0x1b9/0x2e0
[ 5353.765244] vfs_getattr_nosec+0xf7/0x140
[ 5353.765249] __do_sys_newfstatat+0xf6/0x2b0
[ 5353.765253] do_syscall_64+0xaa/0x660
...
Steps to Reproduce:
Open Dolphin and interact with a remote resource (e.g., via SFTP/SSH), which
mounts it through kio-fuse.
Leave the mount active or lingering after the connection/interaction is
finished.
Trigger a system suspend (S3 / deep or sidle).
Observed Result:
The network drops or the connection tears down during suspend entry. Meanwhile,
processes like lsof or background filesystem checkers trying to query the
kio-fuse mount point hang in request_wait_answer. The freezer phase times out
after 20 seconds, causing the suspend to fail or behave erratically.
Expected Result:
kio-fuse should gracefully handle network loss or unmount/abort pending
requests when a system power state change (suspend) is initiated, allowing
tasks to unblock and enabling the system to sleep cleanly.
mount output:
tmpfs on /run/user/1000 type tmpfs
(rw,nosuid,nodev,relatime,size=9825288k,nr_inodes=2456322,mode=700,uid=1000,gid=1000,inode64,huge=advise)
portal on /run/user/1000/doc type fuse.portal
(rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)
kio-fuse on /run/user/1000/kio-fuse-JQGCCl type fuse.kio-fuse
(rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)
[email protected]:/ on /run/user/1000/9f311b7129e24eefa1d5ff0e454c1199
type fuse.sshfs (rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)
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