* [Patch] kexec: fix several issues in get_crash_notes()
@ 2011-11-16 13:09 WANG Cong
2011-11-18 2:11 ` Simon Horman
0 siblings, 1 reply; 4+ messages in thread
From: WANG Cong @ 2011-11-16 13:09 UTC (permalink / raw)
To: kexec; +Cc: WANG Cong, horms
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];
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);
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^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Patch] kexec: fix several issues in get_crash_notes()
2011-11-16 13:09 [Patch] kexec: fix several issues in get_crash_notes() WANG Cong
@ 2011-11-18 2:11 ` Simon Horman
2011-11-21 7:43 ` Cong Wang
0 siblings, 1 reply; 4+ messages in thread
From: Simon Horman @ 2011-11-18 2:11 UTC (permalink / raw)
To: WANG Cong; +Cc: kexec
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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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Patch] kexec: fix several issues in get_crash_notes()
2011-11-18 2:11 ` Simon Horman
@ 2011-11-21 7:43 ` Cong Wang
2011-11-21 8:50 ` Simon Horman
0 siblings, 1 reply; 4+ messages in thread
From: Cong Wang @ 2011-11-21 7:43 UTC (permalink / raw)
To: Simon Horman; +Cc: kexec
[-- Attachment #1: Type: text/plain, Size: 1128 bytes --]
On Fri, Nov 18, 2011 at 10:11 AM, Simon Horman <horms@verge.net.au> wrote:
> 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";
Yeah, sure. Below is the new patch.
-------------------->
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>
---
[-- Attachment #2: kexec-tools-fix-get_crash_notes.diff --]
[-- Type: text/x-patch, Size: 893 bytes --]
diff --git a/kexec/arch/i386/crashdump-x86.c b/kexec/arch/i386/crashdump-x86.c
index 98cda72..436797a 100644
--- a/kexec/arch/i386/crashdump-x86.c
+++ b/kexec/arch/i386/crashdump-x86.c
@@ -589,13 +589,12 @@ 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];
+ 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");
if (fp) {
if (fgets(line, sizeof(line), fp) != 0) {
@@ -610,6 +609,7 @@ 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);
[-- Attachment #3: Type: text/plain, Size: 143 bytes --]
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^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Patch] kexec: fix several issues in get_crash_notes()
2011-11-21 7:43 ` Cong Wang
@ 2011-11-21 8:50 ` Simon Horman
0 siblings, 0 replies; 4+ messages in thread
From: Simon Horman @ 2011-11-21 8:50 UTC (permalink / raw)
To: Cong Wang; +Cc: kexec
On Mon, Nov 21, 2011 at 03:43:34PM +0800, Cong Wang wrote:
> On Fri, Nov 18, 2011 at 10:11 AM, Simon Horman <horms@verge.net.au> wrote:
> > 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";
>
> Yeah, sure. Below is the new patch.
> -------------------->
>
> a) We don't need 'crash_notes' array at all, save some bytes on stack.
> b) We forgot to fclose 'fp' before return.
Thanks, applied.
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2011-11-16 13:09 [Patch] kexec: fix several issues in get_crash_notes() WANG Cong
2011-11-18 2:11 ` Simon Horman
2011-11-21 7:43 ` Cong Wang
2011-11-21 8:50 ` Simon Horman
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