From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on gnuweeb.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=ALL_TRUSTED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NO_DNS_FOR_FROM,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.6 Received: from integral2.. (unknown [182.2.70.161]) by gnuweeb.org (Postfix) with ESMTPSA id 95FDE7E730; Tue, 29 Mar 2022 10:47:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org; s=default; t=1648550849; bh=xQLROf1mQKyJFxRsJjuQiVAUI8GU+Wo/R6YJPVHiVwE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WSnV1KwmemuCBpfphq4rfWvdgDUS8kpsXg+KnxzX4XEVkDkXAKI73cIc+aclqdjDl m2ybsuFLrXfciYGO9JkkBUEGcQP/hD3iennfYyPtLjSdYCtnA63SVAkKtJoGw6FYhz /LKOV4G42N6rH53wrNSWdQaSQD0QESHkCVIBO4ZAPEKiXklvSaIhNrz/iIkgu8S5ZS kdwuwP5vQqEow49tZADiIXZAPNxP1wJdXyhT5qmiZieTYZ0gMhqGJzkFesGX0vcoA0 moIy78du6kGSn6MMUqTdJIooT2BGbtyWJbixyuWtGjFVrO0EiJ++m8dKl4BJNQ8f/W sMGXPj1QdAjww== From: Ammar Faizi To: Borislav Petkov , Thomas Gleixner Cc: Ammar Faizi , Alviro Iskandar Setiawan , Dave Hansen , "H. Peter Anvin" , Ingo Molnar , Tony Luck , Yazen Ghannam , Linux Edac Mailing List , Linux Kernel Mailing List , Stable Kernel , GNU/Weeb Mailing List , x86 Mailing List Subject: [PATCH v6 2/2] x86/MCE/AMD: Fix memory leak when `threshold_create_bank()` fails Date: Tue, 29 Mar 2022 17:47:05 +0700 Message-Id: <20220329104705.65256-3-ammarfaizi2@gnuweeb.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220329104705.65256-1-ammarfaizi2@gnuweeb.org> References: <20220329104705.65256-1-ammarfaizi2@gnuweeb.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit List-Id: In mce_threshold_create_device(), if threshold_create_bank() fails, the @bp will be leaked, because the call to mce_threshold_remove_device() will not free the @bp. mce_threshold_remove_device() frees @threshold_banks. At that point, the @bp has not been written to @threshold_banks, @threshold_banks is NULL, so the call is just a nop. Fix this by extracting the cleanup part into a new static function __threshold_remove_device(), then call it from create/remove device functions. Also, eliminate the "goto out_err", just early return inside the loop if the creation fails. Cc: stable@vger.kernel.org # v5.8+ Fixes: 6458de97fc15 ("x86/mce/amd: Straighten CPU hotplug path") Co-developed-by: Alviro Iskandar Setiawan Signed-off-by: Alviro Iskandar Setiawan Co-developed-by: Yazen Ghannam Signed-off-by: Yazen Ghannam Signed-off-by: Ammar Faizi --- v6: - Change the helper function name to __threshold_remove_device(). --- arch/x86/kernel/cpu/mce/amd.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c index 1940d305db1c..d293ae088d6b 100644 --- a/arch/x86/kernel/cpu/mce/amd.c +++ b/arch/x86/kernel/cpu/mce/amd.c @@ -1294,10 +1294,23 @@ static void threshold_remove_bank(struct threshold_bank *bank) kfree(bank); } +static void __threshold_remove_device(struct threshold_bank **bp, + unsigned int numbanks) +{ + unsigned int bank; + + for (bank = 0; bank < numbanks; bank++) { + if (bp[bank]) { + threshold_remove_bank(bp[bank]); + bp[bank] = NULL; + } + } + kfree(bp); +} + int mce_threshold_remove_device(unsigned int cpu) { struct threshold_bank **bp = this_cpu_read(threshold_banks); - unsigned int bank, numbanks = this_cpu_read(mce_num_banks); if (!bp) return 0; @@ -1308,13 +1321,7 @@ int mce_threshold_remove_device(unsigned int cpu) */ this_cpu_write(threshold_banks, NULL); - for (bank = 0; bank < numbanks; bank++) { - if (bp[bank]) { - threshold_remove_bank(bp[bank]); - bp[bank] = NULL; - } - } - kfree(bp); + __threshold_remove_device(bp, this_cpu_read(mce_num_banks)); return 0; } @@ -1351,15 +1358,14 @@ int mce_threshold_create_device(unsigned int cpu) if (!(this_cpu_read(bank_map) & (1 << bank))) continue; err = threshold_create_bank(bp, cpu, bank); - if (err) - goto out_err; + if (err) { + __threshold_remove_device(bp, numbanks); + return err; + } } this_cpu_write(threshold_banks, bp); if (thresholding_irq_en) mce_threshold_vector = amd_threshold_interrupt; return 0; -out_err: - mce_threshold_remove_device(cpu); - return err; } -- Ammar Faizi