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From:   Dinghao Liu <dinghao.liu@zju.edu.cn>
To:     dinghao.liu@zju.edu.cn
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>,
        Colin Ian King <colin.i.king@gmail.com>,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] [v2] perf/x86/uncore: fix a potential double-free in uncore_type_init
Date:   Tue,  5 Dec 2023 17:08:35 +0800
Message-Id: <20231205090835.1652-1-dinghao.liu@zju.edu.cn>
Precedence: bulk

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 <dinghao.liu@zju.edu.cn>
Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
---

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