Attachment 13771 Details for Bug 13058 – git-am fix for 4.6.next

[patch] git-am fix for 4.6.next

bug-13130-4.6.patch (text/plain), 2.06 KB, created by Jeremy Allison on 2017-11-11 04:03:12 UTC

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Creator: Jeremy Allison

Created: 2017-11-11 04:03:12 UTC

Size: 2.06 KB

patch

obsolete

>From 3fa5c8cb248348d9eae5b870e33e81417e0ba06a Mon Sep 17 00:00:00 2001
>From: Volker Lendecke <vl@samba.org>
>Date: Fri, 10 Nov 2017 21:22:26 +0100
>Subject: [PATCH] tevent: Fix a race condition
>
>We can't rely on tctx to exist after we unlocked the mutex. It took a
>while, but this does lead to data corruption. If *tctx is replaced with
>something where tctx->wakeup_fd points to a real, existing file
>descriptor, we're screwed. And by screwed, this means file corruption
>on disk.
>
>Again. I am not tall enough for this business.
>
>http://bholley.net/blog/2015/must-be-this-tall-to-write-multi-threaded-code.html
>
>BUG: https://bugzilla.samba.org/show_bug.cgi?id=13130
>
>Signed-off-by: Volker Lendecke <vl@samba.org>
>Reviewed-by: Jeremy Allison <jra@samba.org>
>
>Autobuild-User(master): Jeremy Allison <jra@samba.org>
>Autobuild-Date(master): Sat Nov 11 03:20:09 CET 2017 on sn-devel-144
>
>(cherry picked from commit 20cfcb7dbc5dd099384b76a76e3d35cf627100b6)
>---
> lib/tevent/tevent_threads.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
>diff --git a/lib/tevent/tevent_threads.c b/lib/tevent/tevent_threads.c
>index 8197323af02..197ad1dfe41 100644
>--- a/lib/tevent/tevent_threads.c
>+++ b/lib/tevent/tevent_threads.c
>@@ -434,7 +434,7 @@ void _tevent_threaded_schedule_immediate(struct tevent_threaded_context *tctx,
> {
> #ifdef HAVE_PTHREAD
> 	struct tevent_context *ev;
>-	int ret;
>+	int ret, wakeup_fd;
> 
> 	ret = pthread_mutex_lock(&tctx->event_ctx_mutex);
> 	if (ret != 0) {
>@@ -442,6 +442,7 @@ void _tevent_threaded_schedule_immediate(struct tevent_threaded_context *tctx,
> 	}
> 
> 	ev = tctx->event_ctx;
>+	wakeup_fd = tctx->wakeup_fd;
> 
> 	ret = pthread_mutex_unlock(&tctx->event_ctx_mutex);
> 	if (ret != 0) {
>@@ -489,7 +490,7 @@ void _tevent_threaded_schedule_immediate(struct tevent_threaded_context *tctx,
> 	 * than a noncontended one. So I'd opt for the lower footprint
> 	 * initially. Maybe we have to change that later.
> 	 */
>-	tevent_common_wakeup_fd(tctx->wakeup_fd);
>+	tevent_common_wakeup_fd(wakeup_fd);
> #else
> 	/*
> 	 * tevent_threaded_context_create() returned NULL with ENOSYS...
>-- 
>2.14.1
>

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