Attachment 13883 Details for Bug 13195 – Backport for v4-7-test

[patch] Backport for v4-7-test

tmp47.diff.txt (text/plain), 1.58 KB, created by Stefan Metzmacher on 2017-12-21 21:18:03 UTC

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Creator: Stefan Metzmacher

Created: 2017-12-21 21:18:03 UTC

Size: 1.58 KB

patch

obsolete

>From 56afbbdd2e51385d946965a2161335c233ade578 Mon Sep 17 00:00:00 2001
>From: Stefan Metzmacher <metze@samba.org>
>Date: Wed, 20 Dec 2017 08:25:19 +0100
>Subject: [PATCH] g_lock: fix cleanup of stale entries in g_lock_trylock()
>
>g_lock_trylock() always incremented the counter 'i', even after cleaning a stale
>entry at position 'i', which means it skipped checking for a conflict against
>the new entry at position 'i'.
>
>As result a process could get a write lock, while there're still
>some read lock holders. Once we get into that problem, also more than
>one write lock are possible.
>
>BUG: https://bugzilla.samba.org/show_bug.cgi?id=13195
>
>Signed-off-by: Stefan Metzmacher <metze@samba.org>
>Reviewed-by: Volker Lendecke <vl@samba.org>
>
>Autobuild-User(master): Volker Lendecke <vl@samba.org>
>Autobuild-Date(master): Wed Dec 20 20:31:48 CET 2017 on sn-devel-144
>(similar to commit 576fb4fb5dc506bf55e5cf87973999dca444149b)
>---
> source3/lib/g_lock.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
>diff --git a/source3/lib/g_lock.c b/source3/lib/g_lock.c
>index 198fe56..76b4af5 100644
>--- a/source3/lib/g_lock.c
>+++ b/source3/lib/g_lock.c
>@@ -301,9 +301,11 @@ static NTSTATUS g_lock_trylock(struct db_record *rec, struct server_id self,
> 		}
> 	}
> 
>-	for (i=0; i<num_locks; i++) {
>+	i=0;
> 
>+	while (i < num_locks) {
> 		if (i == my_lock) {
>+			i++;
> 			continue;
> 		}
> 
>@@ -329,7 +331,9 @@ static NTSTATUS g_lock_trylock(struct db_record *rec, struct server_id self,
> 			locks[i] = locks[num_locks-1];
> 			num_locks -= 1;
> 			modified = true;
>+			continue;
> 		}
>+		i++;
> 	}
> 
> 	if (my_lock >= num_locks) {
>-- 
>1.9.1
>

Flags:

jra: review+
vl: review+

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Attachments on bug 13195: 13881 | 13882 | 13883 | 13884 | 14421