[dpdk-dev,v2] log: Properly reset log_history_size in rte_log_dump_history()

  In rte_log_dump_history() the log_history list is reinitialized without
resetting the log_history_size. In the next call to rte_log_add_in_history()
the log_history_size > RTE_LOG_HISTORY and the code unconditionally tries
to remove the first entry:

Program received signal SIGSEGV, Segmentation fault.
rte_log_add_in_history (
    buf=buf@entry=0x7f02035cd000 "DATAPLANE: 9:dp0s7 link RTM_NEWLINK [dp0s7] <UP,BROADCAST,RUNNING,MULTICAST,LOWER_UP>\nCAST,LOWER_UP>\n", size=size@entry=86)
    at /usr/src/packages/BUILD/lib/librte_eal/common/eal_common_log.c:122

Signed-off-by: Jan Blunck <jblunck@infradead.org>
---
 lib/librte_eal/common/eal_common_log.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
  

On 06/01/2015 11:30 AM, Jan Blunck wrote:
> In rte_log_dump_history() the log_history list is reinitialized without
> resetting the log_history_size. In the next call to rte_log_add_in_history()
> the log_history_size > RTE_LOG_HISTORY and the code unconditionally tries
> to remove the first entry:
> 
> Program received signal SIGSEGV, Segmentation fault.
> rte_log_add_in_history (
>     buf=buf@entry=0x7f02035cd000 "DATAPLANE: 9:dp0s7 link RTM_NEWLINK [dp0s7] <UP,BROADCAST,RUNNING,MULTICAST,LOWER_UP>\nCAST,LOWER_UP>\n", size=size@entry=86)
>     at /usr/src/packages/BUILD/lib/librte_eal/common/eal_common_log.c:122
> 
> Signed-off-by: Jan Blunck <jblunck@infradead.org>

Acked-by: Olivier Matz <olivier.matz@6wind.com>



> ---
>  lib/librte_eal/common/eal_common_log.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/librte_eal/common/eal_common_log.c b/lib/librte_eal/common/eal_common_log.c
> index fe3d7d5..39d6e3f 100644
> --- a/lib/librte_eal/common/eal_common_log.c
> +++ b/lib/librte_eal/common/eal_common_log.c
> @@ -119,7 +119,10 @@ rte_log_add_in_history(const char *buf, size_t size)
>  	/* get a buffer for adding in history */
>  	if (log_history_size > RTE_LOG_HISTORY) {
>  		hist_buf = STAILQ_FIRST(&log_history);
> -		STAILQ_REMOVE_HEAD(&log_history, next);
> +		if (hist_buf) {
> +			STAILQ_REMOVE_HEAD(&log_history, next);
> +			log_history_size--;
> +		}
>  	}
>  	else {
>  		if (rte_mempool_mc_get(log_history_mp, &obj) < 0)
> @@ -234,6 +237,7 @@ rte_log_dump_history(FILE *out)
>  	rte_spinlock_lock(&log_list_lock);
>  	tmp_log_history = log_history;
>  	STAILQ_INIT(&log_history);
> +	log_history_size = 0;
>  	rte_spinlock_unlock(&log_list_lock);
>  
>  	for (i=0; i<RTE_LOG_HISTORY; i++) {
>
  

2015-06-01 11:46, Olivier MATZ:
> On 06/01/2015 11:30 AM, Jan Blunck wrote:
> > In rte_log_dump_history() the log_history list is reinitialized without
> > resetting the log_history_size. In the next call to rte_log_add_in_history()
> > the log_history_size > RTE_LOG_HISTORY and the code unconditionally tries
> > to remove the first entry:
> > 
> > Program received signal SIGSEGV, Segmentation fault.
> > rte_log_add_in_history (
> >     buf=buf@entry=0x7f02035cd000 "DATAPLANE: 9:dp0s7 link RTM_NEWLINK [dp0s7] <UP,BROADCAST,RUNNING,MULTICAST,LOWER_UP>\nCAST,LOWER_UP>\n", size=size@entry=86)
> >     at /usr/src/packages/BUILD/lib/librte_eal/common/eal_common_log.c:122
> > 
> > Signed-off-by: Jan Blunck <jblunck@infradead.org>
> 
> Acked-by: Olivier Matz <olivier.matz@6wind.com>

Applied, thanks

Note: this is a good example of patch title renaming.
As it is a fix, it should start with "fix".
And in general, function name is not a good candidate for a short title.
It becomes:
	log: fix crash after dump
shorter and clearer ;)