x86/oprofile: Fix uninitialized variable use in debug printk (2c78ffec) · Commits · 戴 / test

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>

arch/x86/oprofile/op_model_amd.c

+11 −15

Original line number	Diff line number	Diff line
		@@ -281,31 +281,27 @@ 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 1;
		}

		static inline int get_ibs_offset(void)
		{
		u64 val;

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