linux-kernel - [PATCH] exec: log when wait_for_dump

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1319591228-20397-1-git-send-email-msb@chromium.org>
Date:	Tue, 25 Oct 2011 18:07:08 -0700
From:	Mandeep Singh Baines <msb@...omium.org>
To:	linux-kernel@...r.kernel.org
Cc:	Mandeep Singh Baines <msb@...omium.org>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Neil Horman <nhorman@...driver.com>,
	Earl Chew <earl_chew@...lent.com>,
	Oleg Nesterov <oleg@...hat.com>,
	Andi Kleen <andi@...stfloor.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-fsdevel@...r.kernel.org
Subject: [PATCH] exec: log when wait_for_dump_helpers aborts due to a signal

To allow coredump pipe readers to look at /proc/<pid> of the crashing
process, the kernel waits for the reader to exit. However, the wait
is silently aborted if the crashing process is signalled.

This patch, logs whenever wait_for_dump_helpers is aborted or in order
to assist in debugging cases where /proc/<pid> is gone.

Alternatively, we may want to consider not aborting on a signal. You
could always break the loop by killing the reader process.

Reference: http://crosbug.com/21559
Signed-off-by: Mandeep Singh Baines <msb@...omium.org>
Cc: Alexander Viro <viro@...iv.linux.org.uk>
Cc: Neil Horman <nhorman@...driver.com>
Cc: Earl Chew <earl_chew@...lent.com>
Cc: Oleg Nesterov <oleg@...hat.com>
Cc: Andi Kleen <andi@...stfloor.org>
Cc: Alan Cox <alan@...rguk.ukuu.org.uk>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-fsdevel@...r.kernel.org
---
 fs/exec.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index 25dcbe5..5d4190d 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -2030,7 +2030,14 @@ static void wait_for_dump_helpers(struct file *file)
 	pipe->readers++;
 	pipe->writers--;
 
-	while ((pipe->readers > 1) && (!signal_pending(current))) {
+	while (pipe->readers > 1) {
+		if (signal_pending(current)) {
+			pr_info("wait_for_dump_helpers[%d]: "
+				"aborted due to signal\n",
+				task_pid_nr(current));
+			break;
+		}
+
 		wake_up_interruptible_sync(&pipe->wait);
 		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
 		pipe_wait(pipe);
-- 
1.7.3.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/