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authorIngo Molnar <mingo@elte.hu>2010-10-25 08:41:09 +0200
committerIngo Molnar <mingo@elte.hu>2010-10-25 08:46:20 +0200
commit2c78ffeca98fcd5a1dfd4a322438944506ed5e64 (patch)
tree37a7a9a024a8342828307ca1bcd1c447fbee270a /arch/x86/oprofile/op_model_amd.c
parentaa7b250c252cc8e6b1daf0e1eada5eba42a1a68d (diff)
downloadlinux-2.6.38-lt-ux500-2c78ffeca98fcd5a1dfd4a322438944506ed5e64.tar.gz
x86/oprofile: Fix uninitialized variable use in debug printk
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>
Diffstat (limited to 'arch/x86/oprofile/op_model_amd.c')
-rw-r--r--arch/x86/oprofile/op_model_amd.c26
1 files changed, 11 insertions, 15 deletions
diff --git a/arch/x86/oprofile/op_model_amd.c b/arch/x86/oprofile/op_model_amd.c
index 42fb46f8388..68759e716f0 100644
--- a/arch/x86/oprofile/op_model_amd.c
+++ b/arch/x86/oprofile/op_model_amd.c
@@ -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))
- 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);
+ 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;
+ }
- return 0;
+ return 1;
}
static inline int get_ibs_offset(void)