[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH] linux-user: Use "!= 0" when checking if MAP_FIXED_NOREPLACE
From: |
Laurent Vivier |
Subject: |
Re: [PATCH] linux-user: Use "!= 0" when checking if MAP_FIXED_NOREPLACE is non-zero |
Date: |
Wed, 4 Nov 2020 22:26:06 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.1 |
Le 03/11/2020 à 15:26, Peter Maydell a écrit :
> In pgd_find_hole_fallback(), Coverity doesn't like the use
> of "if (MAP_FIXED_NOREPLACE || ...)" because it's using a
> logical operator on a constant other than 0 or 1 and its
> heuristic thinks we might have intended a bitwise operator
> instead.
>
> The logic is correct (we are checking whether the host really
> has a MAP_FIXED_NOREPLACE or whether we fell back to the
> "#define as 0 to ignore" from osdep.h); make Coverity
> happier by explicitly writing out the comparison with zero.
>
> Fixes: Coverity CID 1431059
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> linux-user/elfload.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> index e19d0b5cb05..0b02a926025 100644
> --- a/linux-user/elfload.c
> +++ b/linux-user/elfload.c
> @@ -2188,7 +2188,8 @@ static uintptr_t pgd_find_hole_fallback(uintptr_t
> guest_size, uintptr_t brk,
> PROT_NONE, flags, -1, 0);
> if (mmap_start != MAP_FAILED) {
> munmap((void *) align_start, guest_size);
> - if (MAP_FIXED_NOREPLACE || mmap_start == (void *)
> align_start) {
> + if (MAP_FIXED_NOREPLACE != 0 ||
> + mmap_start == (void *) align_start) {
> return (uintptr_t) mmap_start + offset;
> }
> }
>
Applied to my linux-user-for-5.2 branch.
Thanks,
Laurent