Re: [Qemu-devel] New Qemu Crash found with evidence of memory corruption

["andrzej zaborowski" <balrogg@gmail.com>]

On 16/12/2007, Andreas Schwab <schwab@suse.de> wrote:
> "Alexey Eremenko" <alexey.eremenko@qumranet.com> writes:
>
> > ======================================================
> > The error seems to be in Qemu's readline.c:
> >
> > if (idx == TERM_MAX_CMDS) {
> > /* Need to get one free slot */
> > free(term_history[0]); <-- Here is the error.
> > memcpy(term_history, &term_history[1],
> > &term_history[TERM_MAX_CMDS] - &term_history[1]);
> > term_history[TERM_MAX_CMDS - 1] = NULL;
> > idx = TERM_MAX_CMDS - 1;
> > }
> >
>
> Please try this:
>
> --- readline.c  09 Dez 2007 19:27:48 +0100      1.7
> +++ readline.c  16 Dez 2007 18:22:43 +0100
> @@ -267,7 +267,7 @@ static void term_hist_add(const char *cm
>             new_entry = hist_entry;
>             /* Put this entry at the end of history */
>             memmove(&term_history[idx], &term_history[idx + 1],
> -                   &term_history[TERM_MAX_CMDS] - &term_history[idx + 1]);
> +                   (TERM_MAX_CMDS - idx + 1) * sizeof(char *));
>             term_history[TERM_MAX_CMDS - 1] = NULL;
>             for (; idx < TERM_MAX_CMDS; idx++) {
>                 if (term_history[idx] == NULL)
> @@ -280,7 +280,7 @@ static void term_hist_add(const char *cm
>         /* Need to get one free slot */
>         free(term_history[0]);
>         memcpy(term_history, &term_history[1],
> -              &term_history[TERM_MAX_CMDS] - &term_history[1]);
> +              (TERM_MAX_CMDS - 1) * sizeof(char *));
>         term_history[TERM_MAX_CMDS - 1] = NULL;
>         idx = TERM_MAX_CMDS - 1;
>      }

This is correct. I remember submitting the exact same fix about a year
and a half ago in the patch to save/restore monitor history between
sessions. By the way would there be interest to have such feature in
mainline cvs?

Regards