TDB mutex support breaks CTDB

[Stefan (metze) Metzmacher]

Am 17.12.2014 um 10:03 schrieb Ralph Böhme:
> Hi Amitay,
> 
> On Wed, Dec 17, 2014 at 07:48:33PM +1100, Amitay Isaacs wrote:
>> I am trying to test samba+ctdb with these changes using nbench torture
>> test, however smbd is crashing in brlock.  I am not sure if this is related
>> or something else is going wrong.  I have attached gdb backtrace.  If you
>> have any ideas on how to debug this, please let me know.
> 
> hey, I just ran into this just yesterday too, sounds like the same
> issue. gdb:
> 
> #6  <signal handler called>
> No symbol table info available.
> #7  0x00007fcfdc8120b5 in brl_conflict_other (lock=0x0, rw_probe=0x7fffab1a3300) at ../source3/locking/brlock.c:233
> No locals.
> #8  0x00007fcfdc814398 in brl_locktest (br_lck=0x7fcfde974870, rw_probe=0x7fffab1a3300) at ../source3/locking/brlock.c:1385
>         ret = true
>         i = 0
>         locks = 0x0
>         fsp = 0x7fcfde974a20
>         __FUNCTION__ = "brl_locktest"
> #9  0x00007fcfdc80e80a in strict_lock_default (fsp=0x7fcfde974a20, plock=0x7fffab1a3300) at ../source3/locking/locking.c:139
>         br_lck = 0x7fcfde974870
>         strict_locking = 2
>         ret = false
>         __FUNCTION__ = "strict_lock_default"
> #10 0x00007fcfdc86cd7c in vfswrap_strict_lock (handle=0x7fcfde967060, fsp=0x7fcfde974a20, plock=0x7fffab1a3300) at ../source3/modules/vfs_default.c:2293
>         __FUNCTION__ = "vfswrap_strict_lock"
> 
> For some reason locks is NULL. My band aid wad disabling strict locking.

I think I found the problem, it's regression introduced with the leases
code.

A possible fix is attached...

metze
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From 725492afcc6faa56f9f58fdf8e99f37167f98bdc Mon Sep 17 00:00:00 2001
From: Stefan Metzmacher <metze at samba.org>
Date: Wed, 17 Dec 2014 10:43:33 +0100
Subject: [PATCH] s3:locking: fix uninitialiazed variable in
 brl_get_locks_readonly_parser()

In a cluster this can be called with an empty record, while
brl_parse_data() relies on an initialized structure.

This is a regression in commit 0dfdd8a3351f0e35a50813e34a0ce59b9c456ba6.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=10911

Signed-off-by: Stefan Metzmacher <metze at samba.org>
---
 source3/locking/brlock.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/source3/locking/brlock.c b/source3/locking/brlock.c
index 6c73c72..7fd3783 100644
--- a/source3/locking/brlock.c
+++ b/source3/locking/brlock.c
@@ -2014,6 +2014,7 @@ static void brl_get_locks_readonly_parser(TDB_DATA key, TDB_DATA data,
 		*state->br_lock = NULL;
 		return;
 	}
+	*br_lck = (struct byte_range_lock) {};
 	if (!brl_parse_data(br_lck, data)) {
 		*state->br_lock = NULL;
 		return;
-- 
1.9.1
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