On Wed, 27 Jul 2016, Mike Travis wrote:
> Fix a problem that occurs if for some reason the UV4 EFI System Table
> is not available, the check inadvertantly can cause a panic.
>
> Reviewed-by: Dimitri Sivanich <sivanich@xxxxxxx>
> Reviewed-by: Nathan Zimmer <nzimmer@xxxxxxx>
> Tested-by: Frank Ramsay <framsay@xxxxxxx>
> Tested-by: John Estabrook <estabrook@xxxxxxx>
> Signed-off-by: Mike Travis <travis@xxxxxxx>
> ---
> arch/x86/platform/uv/bios_uv.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> --- linux-3.12.orig/arch/x86/platform/uv/bios_uv.c
> +++ linux-3.12/arch/x86/platform/uv/bios_uv.c
> @@ -201,11 +201,12 @@ void uv_bios_init(void)
> }
>
> if (uv_systab->revision >= UV_SYSTAB_VERSION_UV4) {
> + int size = uv_systab->size;
> +
> iounmap(uv_systab);
> - uv_systab = ioremap(efi.uv_systab, uv_systab->size);
I think the changelog is bogus. What's happening here is a classic use after
unmap, which you avoid by this change.
> + uv_systab = ioremap(efi.uv_systab, size);
Hmm?
tglx
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