Messages in this thread | | | Subject | Re: [PATCH] x86: eas should not be NULL when it is referenced | From | Alexander Antonov <> | Date | Fri, 25 Jun 2021 16:33:31 +0300 |
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Hello Kan, > On 6/24/2021 3:03 PM, Liang, Kan wrote: >> I think the NULL pointer dereference of eas should not happen, >> because die is -1 if eas is NULL. But the whole error handling path >> looks fragile. >> >> We already fixed one issue caused by it in commit ID f797f05d917f >> ("perf/x86/intel/uncore: Fix for iio mapping on Skylake Server") >> https://lore.kernel.org/lkml/160149233331.7002.10919231011379055356.tip-bot2@tip-bot2/ >> >> >> Maybe something as below? >> >> From 3de81ba3b04262ef3346297d82f6c4ffb4af7029 Mon Sep 17 00:00:00 2001 >> From: Kan Liang <kan.liang@linux.intel.com> >> Date: Thu, 24 Jun 2021 11:17:57 -0700 >> Subject: [PATCH] perf/x86/intel/uncore: Clean up error handling path >> of iio mapping >> >> The error handling path of iio mapping looks fragile. We already fixed >> one issue caused by it, commit ID f797f05d917f ("perf/x86/intel/uncore: >> Fix for iio mapping on Skylake Server"). Clean up the error handling >> path and make the code robust. I didn't catch why does the current error handling path look fragile? Are there cases when it works incorrect?
Thanks, Alexander >> >> Reported-by: gushengxian <gushengxian@yulong.com> >> Signed-off-by: Kan Liang <kan.liang@linux.intel.com> >> --- >> arch/x86/events/intel/uncore_snbep.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/events/intel/uncore_snbep.c >> b/arch/x86/events/intel/uncore_snbep.c >> index 7622762..6d4a5a9 100644 >> --- a/arch/x86/events/intel/uncore_snbep.c >> +++ b/arch/x86/events/intel/uncore_snbep.c >> @@ -3802,11 +3802,11 @@ pmu_iio_set_mapping(struct intel_uncore_type >> *type, struct attribute_group *ag) >> /* One more for NULL. */ >> attrs = kcalloc((uncore_max_dies() + 1), sizeof(*attrs), >> GFP_KERNEL); >> if (!attrs) >> - goto err; >> + goto clear_topology; >> >> eas = kcalloc(uncore_max_dies(), sizeof(*eas), GFP_KERNEL); >> if (!eas) >> - goto err; >> + goto clear_attrs; >> >> for (die = 0; die < uncore_max_dies(); die++) { >> sprintf(buf, "die%ld", die); >> @@ -3827,7 +3827,9 @@ pmu_iio_set_mapping(struct intel_uncore_type >> *type, struct attribute_group *ag) >> for (; die >= 0; die--) >> kfree(eas[die].attr.attr.name); >> kfree(eas); >> +clear_attrs: >> kfree(attrs); >> +clear_topology: >> kfree(type->topology); >> clear_attr_update: >> type->attr_update = NULL;
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