Re: [PULL 01/26] linux-user: Add infrastructure for a signal trampoline page

[Peter Maydell <peter.maydell@linaro.org>]

On Mon, 4 Oct 2021 at 08:44, Laurent Vivier <laurent@vivier.eu> wrote:
>
> From: Richard Henderson <richard.henderson@linaro.org>
>
> Allocate a page to hold the signal trampoline(s).
> Invoke a guest-specific hook to fill in the contents
> of the page before marking it read-execute again.

Hi; Coverity complains here about a missing error check
(CID 1464101):

>
> +    /*
> +     * TODO: load a vdso, which would also contain the signal trampolines.
> +     * Otherwise, allocate a private page to hold them.
> +     */
> +    if (TARGET_ARCH_HAS_SIGTRAMP_PAGE) {
> +        abi_ulong tramp_page = target_mmap(0, TARGET_PAGE_SIZE,
> +                                           PROT_READ | PROT_WRITE,
> +                                           MAP_PRIVATE | MAP_ANON, -1, 0);

target_mmap() can fail and return -1, but we don't check for that and
instead assume it's always valid.

> +        setup_sigtramp(tramp_page);
> +        target_mprotect(tramp_page, TARGET_PAGE_SIZE, PROT_READ | PROT_EXEC);
> +    }
> +

thanks
-- PMM