2023-12-05 09:09:46

by Dinghao Liu

[permalink] [raw]
Subject: [PATCH] [v2] perf/x86/uncore: fix a potential double-free in uncore_type_init

When kzalloc for pmus[i].boxes fails, we should clean up pmus
to prevent memleak. However, when kzalloc for attr_group fails,
pmus has been assigned to type->pmus, and freeing will be done
later on by the callers. The chain is:

uncore_pci_init
|->uncore_types_init
| |->uncore_type_init (first free)
|
|->uncore_types_exit
|->uncore_type_exit (second free)

Therefore, freeing pmus in uncore_type_init may cause a
double-free. Fix this by setting type->pmus to NULL after kfree.

Fixes: 629eb703d3e4 ("perf/x86/intel/uncore: Fix memory leaks on allocation failures")
Signed-off-by: Dinghao Liu <[email protected]>
Reviewed-by: Zhenyu Wang <[email protected]>
---

Changelog:

v2: Improving the call trace description.
---
arch/x86/events/intel/uncore.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index 01023aa5125b..d80445a24011 100644
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -1041,6 +1041,7 @@ static int __init uncore_type_init(struct intel_uncore_type *type, bool setid)
for (i = 0; i < type->num_boxes; i++)
kfree(pmus[i].boxes);
kfree(pmus);
+ type->pmus = NULL;

return -ENOMEM;
}
--
2.17.1