Re: [Qemu-devel] [PATCH] linux-user: Do not subtract offset from end address

["Andreas Färber" <afaerber@suse.de>]

Am 06.11.2014 um 20:43 schrieb Tom Musta:
> When computing the upper address of a program segment, do not subtract the
> offset from the virtual address; instead compute the sum of the virtual address
> and the memory size.

Note that this reads a bit weird as both old and new code are adding,
not subtracting.

Regards,
Andreas

> 
> Signed-off-by: Tom Musta <tommusta@gmail.com>
> ---
> 
> Please include this patch in QEMU 2.2.  
> 
> Commit a93934fecd4dffc9d4b452b670c9506be5dea30d injected a regression of Linux
> User Mode that I was able to detect on PowerPC 64 (but not x86).  I suspect that
> large page size on the host has something to do with it.  In any case, that commit
> adjusted the lower address of a program segment by the program header's offset 
> field.  However, it also inadvertantly adjusted the upper address by the offset also.
> 
>  linux-user/elfload.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> index 84123ba..e2596a4 100644
> --- a/linux-user/elfload.c
> +++ b/linux-user/elfload.c
> @@ -1824,7 +1824,7 @@ static void load_elf_image(const char *image_name, int image_fd,
>              if (a < loaddr) {
>                  loaddr = a;
>              }
> -            a += phdr[i].p_memsz;
> +            a = phdr[i].p_vaddr + phdr[i].p_memsz;
>              if (a > hiaddr) {
>                  hiaddr = a;
>              }
> 


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