[PATCH i-g-t v2 2/3] lib/igt_kmod: Make sure errno is not already set before unbinding

[Lucas De Marchi]

On Thu, Dec 19, 2024 at 03:05:16PM -0800, Daniele Ceraolo Spurio wrote:
>We assert that errno is zero after unbinding, so we need to make sure it
>wasn't already non-zero beforehand or we might incorrectly fail.
>
>Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
>Cc: Lucas De Marchi <lucas.demarchi at intel.com>
>---
>The non-zero starting errno hitting the assert is reproed when using
>unbind in the 1915 reload-with-fault-injection test:
>https://intel-gfx-ci.01.org/tree/drm-tip/IGTPW_12349/shard-snb5/igt@i915_module_load@reload-with-fault-injection.html

yeah, but I think I made a mistake checking for errno. Checking it
outside of a call to libc is odd.


I'd rather remove both the assert and the setting to 0:

if we have an empty dir we won't ever reach the `errno = 0`, making it
the same as the `if (!dir)` in which we are already returning 0.


This would be a

Fixes: cb008246b0c7 ("lib/igt_kmod: Rewrite xe unload logic")

thanks
Lucas De Marchi

>
> lib/igt_kmod.c | 2 ++
> 1 file changed, 2 insertions(+)
>
>diff --git a/lib/igt_kmod.c b/lib/igt_kmod.c
>index d73cb4101..a008b3c29 100644
>--- a/lib/igt_kmod.c
>+++ b/lib/igt_kmod.c
>@@ -662,6 +662,8 @@ int igt_kmod_unbind(const char *mod_name)
> 	int dirlen;
> 	DIR *dir;
>
>+	errno = 0;
>+
> 	dirlen = snprintf(path, sizeof(path), "/sys/module/%s/drivers/pci:%s/",
> 			  mod_name, mod_name);
> 	igt_assert(dirlen < sizeof(path));
>-- 
>2.43.0
>