Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933945Ab2KZRNx (ORCPT ); Mon, 26 Nov 2012 12:13:53 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:48082 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933912Ab2KZRNo (ORCPT ); Mon, 26 Nov 2012 12:13:44 -0500 From: Herton Ronaldo Krzesinski To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Doug Thompson , Andrew Morton , Borislav Petkov , Herton Ronaldo Krzesinski Subject: [PATCH 221/270] amd64_edac:__amd64_set_scrub_rate(): avoid overindexing scrubrates[] Date: Mon, 26 Nov 2012 14:58:31 -0200 Message-Id: <1353949160-26803-222-git-send-email-herton.krzesinski@canonical.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1353949160-26803-1-git-send-email-herton.krzesinski@canonical.com> References: <1353949160-26803-1-git-send-email-herton.krzesinski@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2464 Lines: 67 3.5.7u1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Andrew Morton commit 168bfeef7bba3f9784f7540b053e4ac72b769ce9 upstream. If none of the elements in scrubrates[] matches, this loop will cause __amd64_set_scrub_rate() to incorrectly use the n+1th element. As the function is designed to use the final scrubrates[] element in the case of no match, we can fix this bug by simply terminating the array search at the n-1th element. Boris: this code is fragile anyway, see here why: http://marc.info/?l=linux-kernel&m=135102834131236&w=2 It will be rewritten more robustly soonish. Reported-by: Denis Kirjanov Cc: Doug Thompson Signed-off-by: Andrew Morton Signed-off-by: Borislav Petkov Signed-off-by: Herton Ronaldo Krzesinski --- drivers/edac/amd64_edac.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c index 7be9b72..a814ea8 100644 --- a/drivers/edac/amd64_edac.c +++ b/drivers/edac/amd64_edac.c @@ -170,8 +170,11 @@ static int __amd64_set_scrub_rate(struct pci_dev *ctl, u32 new_bw, u32 min_rate) * memory controller and apply to register. Search for the first * bandwidth entry that is greater or equal than the setting requested * and program that. If at last entry, turn off DRAM scrubbing. + * + * If no suitable bandwidth is found, turn off DRAM scrubbing entirely + * by falling back to the last element in scrubrates[]. */ - for (i = 0; i < ARRAY_SIZE(scrubrates); i++) { + for (i = 0; i < ARRAY_SIZE(scrubrates) - 1; i++) { /* * skip scrub rates which aren't recommended * (see F10 BKDG, F3x58) @@ -181,12 +184,6 @@ static int __amd64_set_scrub_rate(struct pci_dev *ctl, u32 new_bw, u32 min_rate) if (scrubrates[i].bandwidth <= new_bw) break; - - /* - * if no suitable bandwidth found, turn off DRAM scrubbing - * entirely by falling back to the last element in the - * scrubrates array. - */ } scrubval = scrubrates[i].scrubval; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/