Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932165AbZKXGAE (ORCPT ); Tue, 24 Nov 2009 01:00:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753485AbZKXGAE (ORCPT ); Tue, 24 Nov 2009 01:00:04 -0500 Received: from TYO201.gate.nec.co.jp ([202.32.8.193]:42966 "EHLO tyo201.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752974AbZKXGAC (ORCPT ); Tue, 24 Nov 2009 01:00:02 -0500 Date: Tue, 24 Nov 2009 14:57:59 +0900 From: Daisuke Nishimura To: Andrew Morton Cc: LKML , linux-mm , stable , Balbir Singh , David Rientjes , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Daisuke Nishimura Subject: [BUGFIX][PATCH -mmotm] memcg: avoid oom-killing innocent task in case of use_hierarchy Message-Id: <20091124145759.194cfc9f.nishimura@mxp.nes.nec.co.jp> Organization: NEC Soft, Ltd. X-Mailer: Sylpheed 2.6.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3754 Lines: 112 task_in_mem_cgroup(), which is called by select_bad_process() to check whether a task can be a candidate for being oom-killed from memcg's limit, checks "curr->use_hierarchy"("curr" is the mem_cgroup the task belongs to). But this check return true(it's false positive) when: /00 use_hierarchy == 0 <- hitting limit /00/aa use_hierarchy == 1 <- "curr" This leads to killing an innocent task in 00/aa. This patch is a fix for this bug. And this patch also fixes the arg for mem_cgroup_print_oom_info(). We should print information of mem_cgroup which the task being killed, not current, belongs to. Signed-off-by: Daisuke Nishimura --- The bug exists and should be fixed in 2.6.31.y too. I'll post a patch for -stable later. mm/memcontrol.c | 4 ++-- mm/oom_kill.c | 13 +++++++------ 2 files changed, 9 insertions(+), 8 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ea00a93..d02f9f8 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -783,7 +783,7 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) task_unlock(task); if (!curr) return 0; - if (curr->use_hierarchy) + if (mem->use_hierarchy) ret = css_is_ancestor(&curr->css, &mem->css); else ret = (curr == mem); @@ -1032,7 +1032,7 @@ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) static char memcg_name[PATH_MAX]; int ret; - if (!memcg) + if (!memcg || !p) return; diff --git a/mm/oom_kill.c b/mm/oom_kill.c index ab04537..be56461 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -356,7 +356,8 @@ static void dump_tasks(const struct mem_cgroup *mem) } while_each_thread(g, p); } -static void dump_header(gfp_t gfp_mask, int order, struct mem_cgroup *mem) +static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order, + struct mem_cgroup *mem) { pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, " "oom_adj=%d\n", @@ -365,7 +366,7 @@ static void dump_header(gfp_t gfp_mask, int order, struct mem_cgroup *mem) cpuset_print_task_mems_allowed(current); task_unlock(current); dump_stack(); - mem_cgroup_print_oom_info(mem, current); + mem_cgroup_print_oom_info(mem, p); show_mem(); if (sysctl_oom_dump_tasks) dump_tasks(mem); @@ -440,7 +441,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, struct task_struct *c; if (printk_ratelimit()) - dump_header(gfp_mask, order, mem); + dump_header(p, gfp_mask, order, mem); /* * If the task is already exiting, don't alarm the sysadmin or kill @@ -576,7 +577,7 @@ retry: /* Found nothing?!?! Either we hang forever, or we panic. */ if (!p) { read_unlock(&tasklist_lock); - dump_header(gfp_mask, order, NULL); + dump_header(NULL, gfp_mask, order, NULL); panic("Out of memory and no killable processes...\n"); } @@ -644,7 +645,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, return; if (sysctl_panic_on_oom == 2) { - dump_header(gfp_mask, order, NULL); + dump_header(NULL, gfp_mask, order, NULL); panic("out of memory. Compulsory panic_on_oom is selected.\n"); } @@ -663,7 +664,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, case CONSTRAINT_NONE: if (sysctl_panic_on_oom) { - dump_header(gfp_mask, order, NULL); + dump_header(NULL, gfp_mask, order, NULL); panic("out of memory. panic_on_oom is selected\n"); } /* Fall-through */ -- 1.5.6.1 -- 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/