* christian.ehrha...@canonical.com (christian.ehrha...@canonical.com) wrote:
> From: Christian Ehrhardt <christian.ehrha...@canonical.com>
>
> The virtiofsd currently crashes when used with glibc 2.35.
> That is due to the rseq system call being added to every thread
> creation [1][2].
>
> [1]: https://www.efficios.com/blog/2019/02/08/linux-restartable-sequences/
> [2]: https://sourceware.org/pipermail/libc-alpha/2022-February/136040.html
>
> This happens not at daemon start, but when a guest connects
>
> /usr/lib/qemu/virtiofsd -f --socket-path=/tmp/testvfsd -o sandbox=chroot \
> -o source=/var/guests/j-virtiofs --socket-group=kvm
> virtio_session_mount: Waiting for vhost-user socket connection...
> # start ok, now guest will connect
> virtio_session_mount: Received vhost-user socket connection
> virtio_loop: Entry
> fv_queue_set_started: qidx=0 started=1
> fv_queue_set_started: qidx=1 started=1
> Bad system call (core dumped)
>
> We have to put rseq on the seccomp allowlist to avoid that the daemon
> is crashing in this case.
>
> Reported-by: Michael Hudson-Doyle <michael.hud...@canonical.com>
> Signed-off-by: Christian Ehrhardt <christian.ehrha...@canonical.com>
Thanks! I bet this is going to pop up in zillions of programs.
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> ---
> tools/virtiofsd/passthrough_seccomp.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/tools/virtiofsd/passthrough_seccomp.c
> b/tools/virtiofsd/passthrough_seccomp.c
> index a3ce9f898d..21b8f53bd9 100644
> --- a/tools/virtiofsd/passthrough_seccomp.c
> +++ b/tools/virtiofsd/passthrough_seccomp.c
> @@ -116,6 +116,9 @@ static const int syscall_allowlist[] = {
> SCMP_SYS(write),
> SCMP_SYS(writev),
> SCMP_SYS(umask),
> +#ifdef __NR_rseq
> + SCMP_SYS(rseq), /* required since glibc 2.35 */
> +#endif
> };
>
> /* Syscalls used when --syslog is enabled */
> --
> 2.35.0
>
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
