Re: [PATCH 2/3] fsstress: bypass io_uring testing if io_uring_queue_init returns EPERM

[Zorro Lang <zlang@redhat.com>]

On Wed, Mar 06, 2024 at 10:57:08AM -0500, Jeff Moyer wrote:
> Zorro Lang <zlang@kernel.org> writes:
> 
> > I found the io_uring testing still fails as:
> >   io_uring_queue_init failed
> > even if kernel supports io_uring feature.
> >
> > That because of the /proc/sys/kernel/io_uring_disabled isn't 0.
> >
> > Different value means:
> >   0 All processes can create io_uring instances as normal.
> >   1 io_uring creation is disabled (io_uring_setup() will fail with
> >     -EPERM) for unprivileged processes not in the io_uring_group
> >     group. Existing io_uring instances can still be used.  See the
> >     documentation for io_uring_group for more information.
> >   2 io_uring creation is disabled for all processes. io_uring_setup()
> >     always fails with -EPERM. Existing io_uring instances can still
> >     be used.
> >
> > So besides the CONFIG_IO_URING kernel config, there's another switch
> > can on or off the io_uring supporting. And the "2" or "1" might be
> > the default on some systems.
> >
> > On this situation the io_uring_queue_init returns -EPERM, so I change
> > the fsstress to ignore io_uring testing if io_uring_queue_init returns
> > -ENOSYS or -EPERM. And print different verbose message for debug.
> >
> > Signed-off-by: Zorro Lang <zlang@kernel.org>
> > ---
> >  ltp/fsstress.c | 15 +++++++++++++--
> >  1 file changed, 13 insertions(+), 2 deletions(-)
> >
> > diff --git a/ltp/fsstress.c b/ltp/fsstress.c
> > index 482395c4..9c75f27b 100644
> > --- a/ltp/fsstress.c
> > +++ b/ltp/fsstress.c
> > @@ -762,12 +762,23 @@ int main(int argc, char **argv)
> >  #endif
> >  #ifdef URING
> >  			have_io_uring = true;
> > -			/* If ENOSYS, just ignore uring, other errors are fatal. */
> > +			/*
> > +			 * If ENOSYS, just ignore uring, due to kernel doesn't support it.
> > +			 * If EPERM, might due to sysctl kernel.io_uring_disabled isn't 0,
> > +			 *           or some selinux policies, etc.
> > +			 * Other errors are fatal.
> > +			 */
> >  			if ((c = io_uring_queue_init(URING_ENTRIES, &ring, 0)) != 0) {
> >  				if (c == -ENOSYS) {
> >  					have_io_uring = false;
> > +					if (verbose)
> > +						printf("io_uring isn't supported by kernel\n");
> > +				} else if (c == -EPERM) {
> > +					have_io_uring = false;
> > +					if (verbose)
> > +						printf("io_uring isn't allowed, check io_uring_disabled sysctl or selinux policy\n");
> >  				} else {
> > -					fprintf(stderr, "io_uring_queue_init failed\n");
> > +					fprintf(stderr, "io_uring_queue_init failed, errno=%d\n", c);
> 
> I think you want to use -c here, right?

Sure, will change that, thanks!

> 
> Other than that:
> 
> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
> 
>