Re: [PATCH v4 2/3] powerpc/fadump: Use the correct VMCOREINFO_NOTE_SIZE for phdr

From: Dave Young
Date: Wed Apr 26 2017 - 03:11:43 EST


Ccing ppc list
On 04/20/17 at 07:39pm, Xunlei Pang wrote:
> vmcoreinfo_max_size stands for the vmcoreinfo_data, the
> correct one we should use is vmcoreinfo_note whose total
> size is VMCOREINFO_NOTE_SIZE.
>
> Like explained in commit 77019967f06b ("kdump: fix exported
> size of vmcoreinfo note"), it should not affect the actual
> function, but we better fix it, also this change should be
> safe and backward compatible.
>
> After this, we can get rid of variable vmcoreinfo_max_size,
> let's use the corresponding macros directly, fewer variables
> means more safety for vmcoreinfo operation.
>
> Cc: Mahesh Salgaonkar <mahesh@xxxxxxxxxxxxxxxxxx>
> Cc: Hari Bathini <hbathini@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Xunlei Pang <xlpang@xxxxxxxxxx>
> ---
> v3->v4:
> -Rebased on the latest linux-next
>
> arch/powerpc/kernel/fadump.c | 3 +--
> include/linux/crash_core.h | 1 -
> kernel/crash_core.c | 3 +--
> 3 files changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> index 466569e..7bd6cd0 100644
> --- a/arch/powerpc/kernel/fadump.c
> +++ b/arch/powerpc/kernel/fadump.c
> @@ -893,8 +893,7 @@ static int fadump_create_elfcore_headers(char *bufp)
>
> phdr->p_paddr = fadump_relocate(paddr_vmcoreinfo_note());
> phdr->p_offset = phdr->p_paddr;
> - phdr->p_memsz = vmcoreinfo_max_size;
> - phdr->p_filesz = vmcoreinfo_max_size;
> + phdr->p_memsz = phdr->p_filesz = VMCOREINFO_NOTE_SIZE;
>
> /* Increment number of program headers. */
> (elf->e_phnum)++;
> diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
> index ba283a2..7d6bc7b 100644
> --- a/include/linux/crash_core.h
> +++ b/include/linux/crash_core.h
> @@ -55,7 +55,6 @@
>
> extern u32 *vmcoreinfo_note;
> extern size_t vmcoreinfo_size;
> -extern size_t vmcoreinfo_max_size;
>
> Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
> void *data, size_t data_len);
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 0321f04..43cdb00 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -16,7 +16,6 @@
> /* vmcoreinfo stuff */
> static unsigned char *vmcoreinfo_data;
> size_t vmcoreinfo_size;
> -size_t vmcoreinfo_max_size = VMCOREINFO_BYTES;
> u32 *vmcoreinfo_note;
>
> /*
> @@ -343,7 +342,7 @@ void vmcoreinfo_append_str(const char *fmt, ...)
> r = vscnprintf(buf, sizeof(buf), fmt, args);
> va_end(args);
>
> - r = min(r, vmcoreinfo_max_size - vmcoreinfo_size);
> + r = min(r, VMCOREINFO_BYTES - vmcoreinfo_size);
>
> memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
>
> --
> 1.8.3.1
>
>
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Reviewed-by: Dave Young <dyoung@xxxxxxxxxx>

Thanks
Dave