Commit 11d8b058 authored Jul 19, 2017 by Arnd Bergmann Committed by Ingo Molnar Jul 20, 2017

perf/x86: Shut up false-positive -Wmaybe-uninitialized warning



The intialization function checks for various failure scenarios, but
unfortunately the compiler gets a little confused about the possible
combinations, leading to a false-positive build warning when
-Wmaybe-uninitialized is set:

  arch/x86/events/core.c: In function ‘init_hw_perf_events’:
  arch/x86/events/core.c:264:3: warning: ‘reg_fail’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  arch/x86/events/core.c:264:3: warning: ‘val_fail’ may be used uninitialized in this function [-Wmaybe-uninitialized]
     pr_err(FW_BUG "the BIOS has corrupted hw-PMU resources (MSR %x is %Lx)\n",

We can't actually run into this case, so this shuts up the warning
by initializing the variables to a known-invalid state.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170719125310.2487451-2-arnd@arndb.de
Link: https://patchwork.kernel.org/patch/9392595/


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 0e7f0b6c

arch/x86/events/core.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -191,8 +191,8 @@ static void release_pmc_hardware(void) {}

		static bool check_hw_exists(void)
		{
		u64 val, val_fail, val_new= ~0;
		int i, reg, reg_fail, ret = 0;
		u64 val, val_fail = -1, val_new= ~0;
		int i, reg, reg_fail = -1, ret = 0;
		int bios_fail = 0;
		int reg_safe = -1;

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