From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752053AbcB2Rme (ORCPT ); Mon, 29 Feb 2016 12:42:34 -0500 Received: from mail-wm0-f51.google.com ([74.125.82.51]:34677 "EHLO mail-wm0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750718AbcB2Rmc (ORCPT ); Mon, 29 Feb 2016 12:42:32 -0500 From: Michal Hocko To: LKML Cc: Andrew Morton , Oleg Nesterov , , Michal Hocko Subject: [PATCH] uprobes: wait for mmap_sem for write killable Date: Mon, 29 Feb 2016 18:42:23 +0100 Message-Id: <1456767743-18665-1-git-send-email-mhocko@kernel.org> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1456752417-9626-16-git-send-email-mhocko@kernel.org> References: <1456752417-9626-16-git-send-email-mhocko@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Cc: Oleg Nesterov 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 8eef5f55d3f0..fb4a6bcc88ce 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; @@ -1468,7 +1470,8 @@ 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"); } -- 2.7.0