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| author | Ingo Molnar <mingo@elte.hu> | 2010-10-25 10:41:09 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-10-25 10:46:20 +0400 |
| commit | 2c78ffeca98fcd5a1dfd4a322438944506ed5e64 (patch) | |
| tree | 37a7a9a024a8342828307ca1bcd1c447fbee270a /arch/x86/oprofile | |
| parent | aa7b250c252cc8e6b1daf0e1eada5eba42a1a68d (diff) | |
| download | linux-2c78ffeca98fcd5a1dfd4a322438944506ed5e64.tar.xz | |
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')
| -rw-r--r-- | arch/x86/oprofile/op_model_amd.c | 26 |
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 42fb46f83883..68759e716f0f 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) |