Messages in this thread Patch in this message | | | Date | Thu, 20 Jul 2017 03:24:45 -0700 | From | tip-bot for Arnd Bergmann <> | Subject | [tip:x86/urgent] perf/x86: Shut up false-positive -Wmaybe-uninitialized warning |
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Commit-ID: 11d8b05855f3749bcb6c57e2c4052921b9605c77 Gitweb: http://git.kernel.org/tip/11d8b05855f3749bcb6c57e2c4052921b9605c77 Author: Arnd Bergmann <arnd@arndb.de> AuthorDate: Wed, 19 Jul 2017 14:52:59 +0200 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Thu, 20 Jul 2017 10:46:23 +0200
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> --- arch/x86/events/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index ff1ea2f..8e3db8f 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -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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