| Message ID | 20210414140643.620c3adb@xhacker.debian (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm/i915: Fix "mitigations" parsing if i915 is builtin | expand |
On Wed, Apr 14, 2021 at 02:06:43PM +0800, Jisheng Zhang wrote: > I met below error during boot with i915 builtin if pass > "i915.mitigations=off": > [ 0.015589] Booting kernel: `off' invalid for parameter `i915.mitigations' > > The reason is slab subsystem isn't ready at that time, so kstrdup() > returns NULL. Fix this issue by using stack var instead of kstrdup(). > > Fixes: 984cadea032b ("drm/i915: Allow the sysadmin to override security mitigations") > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> > --- > Since v1: > - Ensure "str" is properly terminated. Thanks Ville for pointing this out. > > drivers/gpu/drm/i915/i915_mitigations.c | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_mitigations.c b/drivers/gpu/drm/i915/i915_mitigations.c > index 84f12598d145..231aad5ff46c 100644 > --- a/drivers/gpu/drm/i915/i915_mitigations.c > +++ b/drivers/gpu/drm/i915/i915_mitigations.c > @@ -29,15 +29,14 @@ bool i915_mitigate_clear_residuals(void) > static int mitigations_set(const char *val, const struct kernel_param *kp) > { > unsigned long new = ~0UL; > - char *str, *sep, *tok; > + char str[64], *sep, *tok; > bool first = true; > int err = 0; > > BUILD_BUG_ON(ARRAY_SIZE(names) >= BITS_PER_TYPE(mitigations)); > > - str = kstrdup(val, GFP_KERNEL); > - if (!str) > - return -ENOMEM; > + strncpy(str, val, sizeof(str) - 1); > + str[sizeof(str) - 1] = '\0'; Looks correct, however strscpy() seems to be the thing we should be using these days. > > for (sep = str; (tok = strsep(&sep, ","));) { > bool enable = true; > @@ -86,7 +85,6 @@ static int mitigations_set(const char *val, const struct kernel_param *kp) > break; > } > } > - kfree(str); > if (err) > return err; > > -- > 2.31.0
diff --git a/drivers/gpu/drm/i915/i915_mitigations.c b/drivers/gpu/drm/i915/i915_mitigations.c index 84f12598d145..231aad5ff46c 100644 --- a/drivers/gpu/drm/i915/i915_mitigations.c +++ b/drivers/gpu/drm/i915/i915_mitigations.c @@ -29,15 +29,14 @@ bool i915_mitigate_clear_residuals(void) static int mitigations_set(const char *val, const struct kernel_param *kp) { unsigned long new = ~0UL; - char *str, *sep, *tok; + char str[64], *sep, *tok; bool first = true; int err = 0; BUILD_BUG_ON(ARRAY_SIZE(names) >= BITS_PER_TYPE(mitigations)); - str = kstrdup(val, GFP_KERNEL); - if (!str) - return -ENOMEM; + strncpy(str, val, sizeof(str) - 1); + str[sizeof(str) - 1] = '\0'; for (sep = str; (tok = strsep(&sep, ","));) { bool enable = true; @@ -86,7 +85,6 @@ static int mitigations_set(const char *val, const struct kernel_param *kp) break; } } - kfree(str); if (err) return err;
I met below error during boot with i915 builtin if pass "i915.mitigations=off": [ 0.015589] Booting kernel: `off' invalid for parameter `i915.mitigations' The reason is slab subsystem isn't ready at that time, so kstrdup() returns NULL. Fix this issue by using stack var instead of kstrdup(). Fixes: 984cadea032b ("drm/i915: Allow the sysadmin to override security mitigations") Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> --- Since v1: - Ensure "str" is properly terminated. Thanks Ville for pointing this out. drivers/gpu/drm/i915/i915_mitigations.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)