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x86/oprofile: Fix uninitialized variable use in debug printk

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Stephen Rothwell reported this build warning:

  arch/x86/oprofile/op_model_amd.c: In function 'ibs_eilvt_valid':
  arch/x86/oprofile/op_model_amd.c:289: warning: 'offset' may be used uninitialized in this function

And correctly observed that indeed the variable is used uninitialized in
this function. The result of this bug can be a debug printk with a bogus
value.

Also fix a few more small details that made this function hard to read
and which probably contributed to the bug being introduced to begin with:

 - Use more symmetric error conditions

 - Remove the !0 obfuscation

 - Add newlines to the printk output

 - Remove bogus linebreaks in printk strings and elsewhere

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20101025115736.41d51abe.sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2010-10-25 08:41:09 +02:00
parent aa7b250c25
commit 2c78ffeca9
1 changed files with 11 additions and 15 deletions
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26
arch/x86/oprofile/op_model_amd.c
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@ -281,29 +281,25 @@ static inline int eilvt_is_available(int offset)
static inline int ibs_eilvt_valid(void)
{
u64 val;
int offset;
u64 val;
rdmsrl(MSR_AMD64_IBSCTL, val);
offset = val & IBSCTL_LVT_OFFSET_MASK;
if (!(val & IBSCTL_LVT_OFFSET_VALID)) {
pr_err(FW_BUG "cpu %d, invalid IBS "
"interrupt offset %d (MSR%08X=0x%016llx)",
smp_processor_id(), offset,
MSR_AMD64_IBSCTL, val);
pr_err(FW_BUG "cpu %d, invalid IBS interrupt offset %d (MSR%08X=0x%016llx)\n",
smp_processor_id(), offset, MSR_AMD64_IBSCTL, val);
return 0;
}
offset = val & IBSCTL_LVT_OFFSET_MASK;
if (!eilvt_is_available(offset)) {
pr_err(FW_BUG "cpu %d, IBS interrupt offset %d not available (MSR%08X=0x%016llx)\n",
smp_processor_id(), offset, MSR_AMD64_IBSCTL, val);
return 0;
}
if (eilvt_is_available(offset))
return !0;
pr_err(FW_BUG "cpu %d, IBS interrupt offset %d "
"not available (MSR%08X=0x%016llx)",
smp_processor_id(), offset,
MSR_AMD64_IBSCTL, val);
return 0;
return 1;
}
static inline int get_ibs_offset(void)