Commit 2c78ffec authored by Ingo Molnar's avatar Ingo Molnar
Browse files

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: default avatarStephen 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: default avatarIngo Molnar <mingo@elte.hu>
parent aa7b250c

arch/x86/oprofile/op_model_amd.c

+11 −15
Original line number Original line Diff line number Diff line
@@ -281,31 +281,27 @@ static inline int eilvt_is_available(int offset) 




static inline int ibs_eilvt_valid(void)

static inline int ibs_eilvt_valid(void)

{

{

	u64 val;

	int offset;

	int offset;

	u64 val;





	rdmsrl(MSR_AMD64_IBSCTL, val);

	rdmsrl(MSR_AMD64_IBSCTL, val);

	offset = val & IBSCTL_LVT_OFFSET_MASK;



	if (!(val & IBSCTL_LVT_OFFSET_VALID)) {

	if (!(val & IBSCTL_LVT_OFFSET_VALID)) {

		pr_err(FW_BUG "cpu %d, invalid IBS "

		pr_err(FW_BUG "cpu %d, invalid IBS interrupt offset %d (MSR%08X=0x%016llx)\n",

		       "interrupt offset %d (MSR%08X=0x%016llx)",

		       smp_processor_id(), offset, MSR_AMD64_IBSCTL, val);

		       smp_processor_id(), offset,

		       MSR_AMD64_IBSCTL, val);

		return 0;

		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",

	if (eilvt_is_available(offset))

		       smp_processor_id(), offset, MSR_AMD64_IBSCTL, val);

		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 0;

	}

	}





	return 1;

}



static inline int get_ibs_offset(void)

static inline int get_ibs_offset(void)

{

{

	u64 val;

	u64 val;