Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752394AbcDZM4s (ORCPT ); Tue, 26 Apr 2016 08:56:48 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:35141 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752309AbcDZM4o (ORCPT ); Tue, 26 Apr 2016 08:56:44 -0400 From: Michal Hocko To: , Andrew Morton Cc: LKML , Michal Hocko , Oleg Nesterov , Vlastimil Babka Subject: [PATCH 15/18] uprobes: wait for mmap_sem for write killable Date: Tue, 26 Apr 2016 14:56:22 +0200 Message-Id: <1461675385-5934-16-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: 1488 Lines: 45 From: Michal Hocko xol_add_vma needs 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. Do not warn in dup_xol_work if __create_xol_area failed due to fatal signal pending because this is usually considered a kernel issue. Acked-by: Oleg Nesterov Acked-by: Vlastimil Babka Signed-off-by: Michal Hocko --- kernel/events/uprobes.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 7edc95edfaee..7bed7f63336d 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1130,7 +1130,9 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) struct vm_area_struct *vma; int ret; - down_write(&mm->mmap_sem); + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + if (mm->uprobes_state.xol_area) { ret = -EALREADY; goto fail; @@ -1469,7 +1471,8 @@ static void dup_xol_work(struct callback_head *work) if (current->flags & PF_EXITING) return; - if (!__create_xol_area(current->utask->dup_xol_addr)) + if (!__create_xol_area(current->utask->dup_xol_addr) && + !fatal_signal_pending(current)) uprobe_warn(current, "dup xol area"); } -- 2.8.0.rc3