[CRIU] [PATCH] irmap: don't try to dereference a null pointer

[Pavel Emelyanov]

On 03/09/2016 06:27 PM, Andrey Vagin wrote:
> From: Andrew Vagin <avagin at virtuozzo.com>
> 
> irmap_revalidate() sets a cursor to the next element or null,
> then we try to dereference cursor->next in the for statemant.

Sigh... Is this v2 of "[PATCH 2/7] irmap: don't access a released variable"?

> Signed-off-by: Andrew Vagin <avagin at virtuozzo.com>
> ---
>  criu/irmap.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/criu/irmap.c b/criu/irmap.c
> index c93a995..a69776c 100644
> --- a/criu/irmap.c
> +++ b/criu/irmap.c
> @@ -243,10 +243,12 @@ char *irmap_lookup(unsigned int s_dev, unsigned long i_ino)
>  	timing_start(TIME_IRMAP_RESOLVE);
>  
>  	hv = irmap_hashfn(s_dev, i_ino);
> -	for (p = &cache[hv]; *p; p = &(*p)->next) {
> +	for (p = &cache[hv]; *p; ) {
>  		c = *p;
> -		if (!(c->dev == s_dev && c->ino == i_ino))
> +		if (!(c->dev == s_dev && c->ino == i_ino)) {
> +			p = &(*p)->next;
>  			continue;
> +		}
>  
>  		if (c->revalidate && irmap_revalidate(c, p))
>  			continue;
>