From: Simon Horman <horms@verge.net.au>
To: WANG Cong <xiyou.wangcong@gmail.com>
Cc: kexec@lists.infradead.org
Subject: Re: [Patch] kexec: fix several issues in get_crash_notes()
Date: Fri, 18 Nov 2011 11:11:56 +0900 [thread overview]
Message-ID: <20111118021155.GM14082@verge.net.au> (raw)
In-Reply-To: <1321448966-25163-1-git-send-email-xiyou.wangcong@gmail.com>
On Wed, Nov 16, 2011 at 09:09:26PM +0800, WANG Cong wrote:
> a) We don't need 'crash_notes' array at all, save some bytes on stack.
> b) We forgot to fclose 'fp' before return.
>
> Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
>
> ---
> diff --git a/kexec/arch/i386/crashdump-x86.c b/kexec/arch/i386/crashdump-x86.c
> index 98cda72..333f6ba 100644
> --- a/kexec/arch/i386/crashdump-x86.c
> +++ b/kexec/arch/i386/crashdump-x86.c
> @@ -589,20 +589,18 @@ static int cmdline_add_elfcorehdr(char *cmdline, unsigned long addr)
> */
> static int get_crash_notes(int cpu, uint64_t *addr, uint64_t *len)
> {
> - char crash_notes[PATH_MAX];
I wonder if the following might reduce memory usage:
const char *crash_notes = "/sys/kernel/crash_notes";
> char line[MAX_LINE];
> FILE *fp;
> unsigned long vaddr;
> int count;
>
> - sprintf(crash_notes, "/sys/kernel/crash_notes");
> - fp = fopen(crash_notes, "r");
> + fp = fopen("/sys/kernel/crash_notes", "r");
> if (fp) {
> if (fgets(line, sizeof(line), fp) != 0) {
> count = sscanf(line, "%lx", &vaddr);
> if (count != 1)
> - die("Cannot parse %s: %s\n", crash_notes,
> - strerror(errno));
> + die("Cannot parse /sys/kernel/crash_notes:"
> + " %s\n", strerror(errno));
> }
>
> *addr = x86__pa(vaddr + (cpu * MAX_NOTE_BYTES));
> @@ -610,6 +608,7 @@ static int get_crash_notes(int cpu, uint64_t *addr, uint64_t *len)
> #ifdef DEBUG
> printf("crash_notes addr = %Lx\n", *addr);
> #endif
> + fclose(fp);
> return 0;
> } else
> return get_crash_notes_per_cpu(cpu, addr, len);
>
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
>
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next prev parent reply other threads:[~2011-11-18 2:14 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-16 13:09 [Patch] kexec: fix several issues in get_crash_notes() WANG Cong
2011-11-18 2:11 ` Simon Horman [this message]
2011-11-21 7:43 ` Cong Wang
2011-11-21 8:50 ` Simon Horman
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