On Fri, Sep 17, 2021 at 9:02 AM Philippe Mathieu-Daudé <
f4bug@amsat.org> wrote:
On 9/17/21 4:56 AM, Warner Losh wrote:
> From: Mikaël Urankar <mikael.urankar@gmail.com>
>
> linux-user/mmap.c: Always zero MAP_ANONYMOUS memory in mmap_frag()
Please use it as subject, "bsd-user/mmap: Always zero MAP_ANONYMOUS
memory in mmap_frag()"
Then describe:
Similar to the equivalent linux-user commit e6deac9cf99, ...
OK. I have three commits like this, so I'll go ahead and edit all three.
>
> When mapping MAP_ANONYMOUS memory fragments, still need notice about to
> set it zero, or it will cause issues.
>
> Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
> Reviewed-by: Laurent Vivier <laurent@vivier.eu>
> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
^ These tags were for another file, not this one, please
remove them.
Gotcha. I wasn't completely sure what to do in this case since they
describe that the work is able to be contributed so I could make a case either way.
I'll remove them.
Warner
> [ bsd-user merge by Mikaël Urankar, updated for untagged by Warner Losh ]
> Signed-off-by: Mikaël Urankar <mikael.urankar@gmail.com>
> Signed-off-by: Warner Losh <imp@bsdimp.com>
> ---
> bsd-user/mmap.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
> index b40ab9045f..fc3c1480f5 100644
> --- a/bsd-user/mmap.c
> +++ b/bsd-user/mmap.c
> @@ -180,10 +180,12 @@ static int mmap_frag(abi_ulong real_start,
> if (prot_new != (prot1 | PROT_WRITE))
> mprotect(host_start, qemu_host_page_size, prot_new);
> } else {
> - /* just update the protection */
> if (prot_new != prot1) {
> mprotect(host_start, qemu_host_page_size, prot_new);
> }
> + if (prot_new & PROT_WRITE) {
> + memset(g2h_untagged(start), 0, end - start);
> + }
> }
> return 0;
> }
>