Hi.
Thanks very much! I will try these patches.
-Lixiaokeng
On 2020/7/28 0:45, Benjamin Marzinski wrote:
> On Sat, Jul 25, 2020 at 01:47:01PM +0800, lixiaokeng wrote:
>> When one iscsi device logs in and logs out with the "multipath -r"
>> executed at the same time, memory leak happens in multipathd
>> process.
>>
>> The reason is following. When "multipath -r" is executed, the path
>> will be free in configure function. Before path_discovery executed,
>> iscsi device logs out. Then path_discovery will not find any path and
>> there is no path in the gvecs->pathvec. When map_discovery function
>> is executed, disassemble_map function will be called. Because
>> gvecs->pathvec->slot is empty and is_deamon is 1, a path will be
>> allocated and is not stored in gvecs->pathvec but store in
>> mpp->pg. But when the mpp is removed and freed by remove_map
>> function, the path will not be free and can't be find anymore.
>>
>> The procedure details given as follows,
>> 1."multipath -r" is executed
>> main
>> ->child
>> ->reconfigure
>> ->configure
>> ->path_discovery //after iscsi logout
>> ->map_discovery
>> ->update_multipath_table
>> ->disassemble_map
>> ->alloc_path
>> 2.then "multipath -r" is executed again
>> main
>> main
>> ->child
>> ->reconfigure
>> ->remove_maps_and_stop_waiters
>> ->remove_maps
>>
>> Here, we delete checking is_deamon. Because whether the process is a
>> daemon process or not, we think the path should be add to gvecs->pathvec.
>
> There is more work that needs to be done to besides removing the is_daemon
> check. However, Martin already posted patches that deal with this as
> part of the his large patchset.
>
> https://www.redhat.com/archives/dm-devel/2020-July/msg00245.html
>
> You should take a look at those, and at my comments on them, because they
> should resolve your issue.
>
> -Ben
>
>>
>> Reported-by: Tianxiong Li <lutianxiong@xxxxxxxxxx>
>> Signed-off-by: Lixiaokeng <lixiaokeng@xxxxxxxxxx>
>> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@xxxxxxxxxx>
>>
>> ---
>> libmultipath/dmparser.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/libmultipath/dmparser.c b/libmultipath/dmparser.c
>> index b856a07f..d556f642 100644
>> --- a/libmultipath/dmparser.c
>> +++ b/libmultipath/dmparser.c
>> @@ -315,7 +315,7 @@ int disassemble_map(vector pathvec, char *params, struct multipath *mpp,
>> WWID_SIZE);
>> }
>> /* Only call this in multipath client mode */
>> - if (!is_daemon && store_path(pathvec, pp))
>> + if (store_path(pathvec, pp))
>> goto out1;
>> } else {
>> if (!strlen(pp->wwid) &&
>> --
>
>
> .
>
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