[Virtio-fs] [PATCH v2] virtiofsd: remove SCMP_FLTATTR_CTL_TSYNC flag

[Virtio-fs] [PATCH v2] virtiofsd: remove SCMP_FLTATTR_CTL_TSYNC flag

[Eric Ren]

SCMP_FLTATTR_CTL_TSYNC flag is only available on
Linux Kernel 3.17 or greater. Older host kernel
fails virtiofsd, limiting virtiofsd use.

And, confirmed from Stefan Hajnoczi:
"""
There are no threads when setup_seccomp() is invoked so the TSYNC
attribute is not required.

Please remove the TSYNC call.  Then we don't need to worry about version
or feature checks.
"""

Signed-off-by: Eric Ren <renzhen@linux.alibaba.com>
---
 contrib/virtiofsd/seccomp.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/contrib/virtiofsd/seccomp.c b/contrib/virtiofsd/seccomp.c
index 4e388adc9c..28b2bbf0cf 100644
--- a/contrib/virtiofsd/seccomp.c
+++ b/contrib/virtiofsd/seccomp.c
@@ -92,10 +92,6 @@ void setup_seccomp(void)
 		err(1, "seccomp_init()");
 	}
 
-	if (seccomp_attr_set(ctx, SCMP_FLTATR_CTL_TSYNC, 1) != 0) {
-		err(1, "seccomp_attr_set(ctx, SCMP_FLTATTR_CTL_TSYNC, 1)");
-	}
-
 	for (i = 0; i < G_N_ELEMENTS(syscall_whitelist); i++) {
 		if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW,
 				     syscall_whitelist[i], 0) != 0) {
-- 
2.17.2 (Apple Git-113)

Re: [Virtio-fs] [PATCH v2] virtiofsd: remove SCMP_FLTATTR_CTL_TSYNC flag

[Stefan Hajnoczi]

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On Mon, Jul 15, 2019 at 11:09:51AM +0800, Eric Ren wrote:
> SCMP_FLTATTR_CTL_TSYNC flag is only available on
> Linux Kernel 3.17 or greater. Older host kernel
> fails virtiofsd, limiting virtiofsd use.
> 
> And, confirmed from Stefan Hajnoczi:
> """
> There are no threads when setup_seccomp() is invoked so the TSYNC
> attribute is not required.
> 
> Please remove the TSYNC call.  Then we don't need to worry about version
> or feature checks.
> """
> 
> Signed-off-by: Eric Ren <renzhen@linux.alibaba.com>
> ---
>  contrib/virtiofsd/seccomp.c | 4 ----
>  1 file changed, 4 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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Re: [Virtio-fs] [PATCH v2] virtiofsd: remove SCMP_FLTATTR_CTL_TSYNC flag

[Dr. David Alan Gilbert]

* Stefan Hajnoczi (stefanha@redhat.com) wrote:
> On Mon, Jul 15, 2019 at 11:09:51AM +0800, Eric Ren wrote:
> > SCMP_FLTATTR_CTL_TSYNC flag is only available on
> > Linux Kernel 3.17 or greater. Older host kernel
> > fails virtiofsd, limiting virtiofsd use.
> > 
> > And, confirmed from Stefan Hajnoczi:
> > """
> > There are no threads when setup_seccomp() is invoked so the TSYNC
> > attribute is not required.
> > 
> > Please remove the TSYNC call.  Then we don't need to worry about version
> > or feature checks.
> > """
> > 
> > Signed-off-by: Eric Ren <renzhen@linux.alibaba.com>
> > ---
> >  contrib/virtiofsd/seccomp.c | 4 ----
> >  1 file changed, 4 deletions(-)
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

Thanks, merged.

--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK