Hi AKASHI
On 04/26/17 at 05:22pm, AKASHI Takahiro wrote:
> The current kexec_locate_mem_hole(kbuf.top_down == 1) stops searching at
> the first memory region that has enough space for requested size even if
> some of higher regions may also have.
> This behavior is not consistent with locate_hole(hole_end == -1) function
> of kexec-tools.
Have you seen actual bug happened or just observing this during code
review?
Till now seems we do not see any reports about this.
>
> This patch fixes the bug, going though all the memory regions anyway.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> ---
> kernel/kexec_file.c | 19 ++++++++++++++-----
> 1 file changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> index b118735fea9d..2f131c0d9017 100644
> --- a/kernel/kexec_file.c
> +++ b/kernel/kexec_file.c
> @@ -373,8 +373,8 @@ static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
> /* If we are here, we found a suitable memory range */
> kbuf->mem = temp_start;
>
> - /* Success, stop navigating through remaining System RAM ranges */
> - return 1;
> + /* always return zero, going through all the System RAM ranges */
> + return 0;
> }
>
> static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
> @@ -439,18 +439,27 @@ static int locate_mem_hole_callback(u64 start, u64 end, void *arg)
> *
> * Return: The memory walk will stop when func returns a non-zero value
> * and that value will be returned. If all free regions are visited without
> - * func returning non-zero, then zero will be returned.
> + * func returning non-zero, then kbuf->mem will be additionally checked
> + * for top-down search.
> + * After all, zero will be returned if none of regions fits.
> */
> int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
> int (*func)(u64, u64, void *))
> {
> + int ret;
> +
> + kbuf->mem = 0;
> if (kbuf->image->type == KEXEC_TYPE_CRASH)
> - return walk_iomem_res_desc(crashk_res.desc,
> + ret = walk_iomem_res_desc(crashk_res.desc,
> IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
> crashk_res.start, crashk_res.end,
> kbuf, func);
> else
> - return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
> + ret = walk_system_ram_res(0, ULONG_MAX, kbuf, func);
> +
> + if (!ret && kbuf->mem)
> + ret = 1; /* found for top-down search */
> + return ret;
> }
>
> /**
> --
> 2.11.1
>
