Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752713AbcDZM6p (ORCPT ); Tue, 26 Apr 2016 08:58:45 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:35956 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752271AbcDZM4m (ORCPT ); Tue, 26 Apr 2016 08:56:42 -0400 From: Michal Hocko To: , Andrew Morton Cc: LKML , Michal Hocko , Alexander Viro , Oleg Nesterov , Vlastimil Babka Subject: [PATCH 13/18] exec: make exec path waiting for mmap_sem killable Date: Tue, 26 Apr 2016 14:56:20 +0200 Message-Id: <1461675385-5934-14-git-send-email-mhocko@kernel.org> X-Mailer: git-send-email 2.8.0.rc3 In-Reply-To: <1461675385-5934-1-git-send-email-mhocko@kernel.org> References: <1461675385-5934-1-git-send-email-mhocko@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1575 Lines: 57 From: Michal Hocko setup_arg_pages requires mmap_sem for write. If the waiting task gets killed by the oom killer it would block oom_reaper from asynchronous address space reclaim and reduce the chances of timely OOM resolving. Wait for the lock in the killable mode and return with EINTR if the task got killed while waiting. All the callers are already handling error path and the fatal signal doesn't need any additional treatment. The same applies to __bprm_mm_init. Cc: Alexander Viro Acked-by: Oleg Nesterov Acked-by: Vlastimil Babka Signed-off-by: Michal Hocko --- fs/exec.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 2f44590d88a9..d7a6ff09bb7a 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -267,7 +267,10 @@ static int __bprm_mm_init(struct linux_binprm *bprm) if (!vma) return -ENOMEM; - down_write(&mm->mmap_sem); + if (down_write_killable(&mm->mmap_sem)) { + err = -EINTR; + goto err_free; + } vma->vm_mm = mm; /* @@ -294,6 +297,7 @@ static int __bprm_mm_init(struct linux_binprm *bprm) return 0; err: up_write(&mm->mmap_sem); +err_free: bprm->vma = NULL; kmem_cache_free(vm_area_cachep, vma); return err; @@ -700,7 +704,9 @@ int setup_arg_pages(struct linux_binprm *bprm, bprm->loader -= stack_shift; bprm->exec -= stack_shift; - down_write(&mm->mmap_sem); + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + vm_flags = VM_STACK_FLAGS; /* -- 2.8.0.rc3