Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964792AbaF3Mba (ORCPT ); Mon, 30 Jun 2014 08:31:30 -0400 Received: from ip4-83-240-18-248.cust.nbox.cz ([83.240.18.248]:53045 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932233AbaF3MbW (ORCPT ); Mon, 30 Jun 2014 08:31:22 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Tony Luck , Naoya Horiguchi , Andi Kleen , Borislav Petkov , Chen Gong , Andrew Morton , Linus Torvalds , Jiri Slaby Subject: [PATCH 3.12 113/181] mm/memory-failure.c-failure: send right signal code to correct thread Date: Mon, 30 Jun 2014 13:52:14 +0200 Message-Id: <11b92053aef791c7da356dcd081916ebdea92dc7.1404128998.git.jslaby@suse.cz> X-Mailer: git-send-email 2.0.0 In-Reply-To: <61844d8e25eb8899b0836afa9796fa239db80f1f.1404128997.git.jslaby@suse.cz> References: <61844d8e25eb8899b0836afa9796fa239db80f1f.1404128997.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tony Luck 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit a70ffcac741d31a406c1d2b832ae43d658e7e1cf upstream. When a thread in a multi-threaded application hits a machine check because of an uncorrectable error in memory - we want to send the SIGBUS with si.si_code = BUS_MCEERR_AR to that thread. Currently we fail to do that if the active thread is not the primary thread in the process. collect_procs() just finds primary threads and this test: if ((flags & MF_ACTION_REQUIRED) && t == current) { will see that the thread we found isn't the current thread and so send a si.si_code = BUS_MCEERR_AO to the primary (and nothing to the active thread at this time). We can fix this by checking whether "current" shares the same mm with the process that collect_procs() said owned the page. If so, we send the SIGBUS to current (with code BUS_MCEERR_AR). Signed-off-by: Tony Luck Signed-off-by: Naoya Horiguchi Reported-by: Otto Bruggeman Cc: Andi Kleen Cc: Borislav Petkov Cc: Chen Gong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Jiri Slaby --- mm/memory-failure.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index ecfbfe520342..fe4873b010eb 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -208,9 +208,9 @@ static int kill_proc(struct task_struct *t, unsigned long addr, int trapno, #endif si.si_addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT; - if ((flags & MF_ACTION_REQUIRED) && t == current) { + if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) { si.si_code = BUS_MCEERR_AR; - ret = force_sig_info(SIGBUS, &si, t); + ret = force_sig_info(SIGBUS, &si, current); } else { /* * Don't use force here, it's convenient if the signal -- 2.0.0 -- 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/