Hello,
We are getting frequent core-dumps on lxcfs on our incus installation.
Actually this is happening for a long time, every once in a while.
Happens on more than one similar server (does not seem hardware related).
Happens on recent incus versions, not on older incus versions.
# incus --version
6.15
# lxcfs --version
"6.0.5"
# uname -a
Linux HOSTNAME 6.16.10-200.fc42.x86_64 #1 SMP PREEMPT_DYNAMIC Thu Oct 2 19:23:55 UTC 2025 x86_64 GNU/Linux
This is Fedora 42 server edition.
Below is a typical core-dump section from lxcfs journalctl.
Sep 08 06:25:01 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/580956/task"
Sep 08 06:33:01 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/599062/task"
Sep 08 06:33:01 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/599010/task"
Sep 08 06:35:08 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/604520/task"
Sep 08 06:39:05 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/615310/task"
Sep 08 06:39:05 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/615311/task"
Sep 08 06:40:02 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/617161/task"
Sep 08 06:45:14 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/630220/task"
Sep 08 06:45:14 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/630224/task"
Sep 08 06:45:14 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/630226/task"
Sep 08 06:46:02 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/630994/task"
Sep 08 06:48:14 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/638602/task"
Sep 08 06:50:09 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/642640/task"
Sep 08 06:52:22 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/647597/task"
Sep 08 07:00:01 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/664616/task"
Sep 08 07:00:01 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/665472/task"
Sep 08 07:00:01 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/665477/task"
Sep 08 07:00:01 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/665478/task"
Sep 08 07:00:12 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/670190/task"
Sep 08 07:00:38 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/674665/task"
Sep 08 07:01:00 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/676068/task"
Sep 08 07:01:05 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/677288/task"
Sep 08 07:02:30 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/682982/task"
Sep 08 07:04:05 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/687981/task"
Sep 08 07:05:14 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/691468/task"
Sep 08 07:05:40 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/691478/task"
Sep 08 07:06:01 HOSTNAME lxcfs[717061]: ../src/proc_loadavg.c: 421: refresh_load: Failed to open "/proc/692643/task"
Sep 08 07:08:02 HOSTNAME lxcfs[717061]: malloc(): unaligned tcache chunk detected
Sep 08 07:08:02 HOSTNAME systemd-coredump[697061]: [🡕] Process 717061 (lxcfs) of user 0 dumped core.
Module libfuse.so.2 from rpm fuse-2.9.9-23.fc42.x86_64
Stack trace of thread 696920:
#0 0x00007f67f1046e9c __pthread_kill_implementation (libc.so.6 + 0x73e9c)
#1 0x00007f67f0fecf3e raise (libc.so.6 + 0x19f3e)
#2 0x00007f67f0fd46d0 abort (libc.so.6 + 0x16d0)
#3 0x00007f67f0fd56f3 __libc_message_impl.cold (libc.so.6 + 0x26f3)
#4 0x00007f67f1051035 malloc_printerr (libc.so.6 + 0x7e035)
#5 0x00007f67f105725c __libc_calloc (libc.so.6 + 0x8425c)
#6 0x00007f67f0fadc10 n/a (/usr/lib64/lxcfs/liblxcfs.so (deleted) + 0x16c10)
#7 0x0000555610756ceb n/a (/usr/bin/lxcfs (deleted) + 0x2ceb)
#8 0x00007f67f11f767c fuse_fs_opendir (libfuse.so.2 + 0x667c)
#9 0x00007f67f11fdf1e fuse_lib_opendir (libfuse.so.2 + 0xcf1e)
#10 0x00007f67f1206eef do_opendir (libfuse.so.2 + 0x15eef)
#11 0x00007f67f1209e43 fuse_ll_process_buf (libfuse.so.2 + 0x18e43)
#12 0x00007f67f1205071 fuse_do_work (libfuse.so.2 + 0x14071)
#13 0x00007f67f1044f54 start_thread (libc.so.6 + 0x71f54)
#14 0x00007f67f10c832c __clone3 (libc.so.6 + 0xf532c)
Stack trace of thread 696925:
#0 0x00007f67f104177e __internal_syscall_cancel (libc.so.6 + 0x6e77e)
#1 0x00007f67f10417a4 __syscall_cancel (libc.so.6 + 0x6e7a4)
#2 0x00007f67f10c7ff1 writev (libc.so.6 + 0xf4ff1)
#3 0x00007f67f1200c80 fuse_kern_chan_send (libfuse.so.2 + 0xfc80)
#4 0x00007f67f12093e1 fuse_send_data_iov.constprop.0 (libfuse.so.2 + 0x183e1)
#5 0x00007f67f12098c7 fuse_reply_data (libfuse.so.2 + 0x188c7)
#6 0x00007f67f11fe22c fuse_lib_read (libfuse.so.2 + 0xd22c)
#7 0x00007f67f1205a5d do_read (libfuse.so.2 + 0x14a5d)
#8 0x00007f67f1209e43 fuse_ll_process_buf (libfuse.so.2 + 0x18e43)
#9 0x00007f67f1205071 fuse_do_work (libfuse.so.2 + 0x14071)
#10 0x00007f67f1044f54 start_thread (libc.so.6 + 0x71f54)
#11 0x00007f67f10c832c __clone3 (libc.so.6 + 0xf532c)
Stack trace of thread 696922:
#0 0x00007f67f104177e __internal_syscall_cancel (libc.so.6 + 0x6e77e)
#1 0x00007f67f10417a4 __syscall_cancel (libc.so.6 + 0x6e7a4)
#2 0x00007f67f10c7ff1 writev (libc.so.6 + 0xf4ff1)
#3 0x00007f67f1200c80 fuse_kern_chan_send (libfuse.so.2 + 0xfc80)
#4 0x00007f67f12053a9 fuse_reply_err (libfuse.so.2 + 0x143a9)
#5 0x00007f67f11fc03e fuse_lib_flush (libfuse.so.2 + 0xb03e)
#6 0x00007f67f1205bb4 do_flush (libfuse.so.2 + 0x14bb4)
#7 0x00007f67f1209e43 fuse_ll_process_buf (libfuse.so.2 + 0x18e43)
#8 0x00007f67f1205071 fuse_do_work (libfuse.so.2 + 0x14071)
#9 0x00007f67f1044f54 start_thread (libc.so.6 + 0x71f54)
#10 0x00007f67f10c832c __clone3 (libc.so.6 + 0xf532c)
Stack trace of thread 696427:
#0 0x00007f67f104d462 __syscall_cancel_arch (libc.so.6 + 0x7a462)
#1 0x00007f67f104175c __internal_syscall_cancel (libc.so.6 + 0x6e75c)
#2 0x00007f67f10417a4 __syscall_cancel (libc.so.6 + 0x6e7a4)
#3 0x00007f67f10bb7fe read (libc.so.6 + 0xe87fe)
#4 0x00007f67f1200b92 fuse_kern_chan_receive (libfuse.so.2 + 0xfb92)
#5 0x00007f67f120a4e5 fuse_ll_receive_buf (libfuse.so.2 + 0x194e5)
#6 0x00007f67f1204ff6 fuse_do_work (libfuse.so.2 + 0x13ff6)
#7 0x00007f67f1044f54 start_thread (libc.so.6 + 0x71f54)
#8 0x00007f67f10c832c __clone3 (libc.so.6 + 0xf532c)
Stack trace of thread 696916:
#0 0x00007f67f104d462 __syscall_cancel_arch (libc.so.6 + 0x7a462)
#1 0x00007f67f104175c __internal_syscall_cancel (libc.so.6 + 0x6e75c)
#2 0x00007f67f10417a4 __syscall_cancel (libc.so.6 + 0x6e7a4)
#3 0x00007f67f10bb7fe read (libc.so.6 + 0xe87fe)
#4 0x00007f67f1200b92 fuse_kern_chan_receive (libfuse.so.2 + 0xfb92)
#5 0x00007f67f120a4e5 fuse_ll_receive_buf (libfuse.so.2 + 0x194e5)
#6 0x00007f67f1204ff6 fuse_do_work (libfuse.so.2 + 0x13ff6)
#7 0x00007f67f1044f54 start_thread (libc.so.6 + 0x71f54)
#8 0x00007f67f10c832c __clone3 (libc.so.6 + 0xf532c)
Stack trace of thread 696915:
#0 0x00007f67f104177e __internal_syscall_cancel (libc.so.6 + 0x6e77e)
#1 0x00007f67f10417a4 __syscall_cancel (libc.so.6 + 0x6e7a4)
#2 0x00007f67f10bb7fe read (libc.so.6 + 0xe87fe)
#3 0x00007f67f0fa96c8 n/a (/usr/lib64/lxcfs/liblxcfs.so (deleted) + 0x126c8)
#4 0x00007f67f0fa9797 n/a (/usr/lib64/lxcfs/liblxcfs.so (deleted) + 0x12797)
#5 0x00007f67f0faaa95 n/a (/usr/lib64/lxcfs/liblxcfs.so (deleted) + 0x13a95)
#6 0x00007f67f0faeca7 n/a (/usr/lib64/lxcfs/liblxcfs.so (deleted) + 0x17ca7)
#7 0x0000555610755a20 n/a (/usr/bin/lxcfs (deleted) + 0x1a20)
#8 0x00007f67f11f94a5 fuse_fs_read_buf (libfuse.so.2 + 0x84a5)
#9 0x00007f67f11fe179 fuse_lib_read (libfuse.so.2 + 0xd179)
#10 0x00007f67f1205a5d do_read (libfuse.so.2 + 0x14a5d)
#11 0x00007f67f1209e43 fuse_ll_process_buf (libfuse.so.2 + 0x18e43)
#12 0x00007f67f1205071 fuse_do_work (libfuse.so.2 + 0x14071)
#13 0x00007f67f1044f54 start_thread (libc.so.6 + 0x71f54)
#14 0x00007f67f10c832c __clone3 (libc.so.6 + 0xf532c)
Stack trace of thread 717061:
#0 0x00007f67f104d462 __syscall_cancel_arch (libc.so.6 + 0x7a462)
#1 0x00007f67f104175c __internal_syscall_cancel (libc.so.6 + 0x6e75c)
#2 0x00007f67f1041dcc __futex_abstimed_wait_common (libc.so.6 + 0x6edcc)
#3 0x00007f67f104d368 __new_sem_wait_slow64.constprop.0 (libc.so.6 + 0x7a368)
#4 0x00007f67f1204ce9 fuse_session_loop_mt (libfuse.so.2 + 0x13ce9)
#5 0x00007f67f120bd6e fuse_loop_mt (libfuse.so.2 + 0x1ad6e)
#6 0x00007f67f120c43d fuse_main_common (libfuse.so.2 + 0x1b43d)
#7 0x0000555610754ea2 n/a (/usr/bin/lxcfs (deleted) + 0xea2)
#8 0x00007f67f0fd6575 __libc_start_call_main (libc.so.6 + 0x3575)
#9 0x00007f67f0fd6628 __libc_start_main@@GLIBC_2.34 (libc.so.6 + 0x3628)
#10 0x0000555610755385 n/a (/usr/bin/lxcfs (deleted) + 0x1385)
ELF object binary architecture: AMD x86-64
Sep 08 07:08:02 HOSTNAME systemd[1]: lxcfs.service: Main process exited, code=dumped, status=6/ABRT
Sep 08 07:08:02 HOSTNAME systemd[1]: lxcfs.service: Failed with result 'core-dump'.
Sep 08 07:08:02 HOSTNAME systemd[1]: lxcfs.service: Consumed 7h 24min 39.040s CPU time, 47.5M memory peak, 4.4M memory swap peak.