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DIR:OUT; SFP:1102; SCL:1; SRVR:DM5PR2101MB0902; H:DM5PR2101MB1032.namprd21.prod.outlook.com; FPR:; SPF:None; PTR:InfoNoRecords; A:1; MX:1; LANG:en; received-spf: None (protection.outlook.com: microsoft.com does not designate permitted sender hosts) authentication-results: spf=none (sender IP is ) smtp.mailfrom=Alexander.Levin@microsoft.com; x-microsoft-antispam-message-info: aSLo/Jv2NCqkxKpQeiYo67l1MJNRPklcfWixPzuMARvqL5tP1u1miFFyvFuafg3LTfbytntA2M+TSfWAU0pmMUU0QQUlU2w4BLtltmC7QzRapJno5tEn90GXkfv29YipAE/mtiUBKKi8eNfuUTcb0tFY+Rbc2cj2xDJPJVxZBUI= spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-ID: <6023A2CB4138584598B1ABB4B8DAD59F@namprd21.prod.outlook.com> MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: 103c321b-c79b-47c7-6a1f-08d57f8a959f X-MS-Exchange-CrossTenant-originalarrivaltime: 01 Mar 2018 15:27:39.5268 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR2101MB0902 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Arnd Bergmann This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. -- 2.14.1 =============== [ Upstream commit 11d8b05855f3749bcb6c57e2c4052921b9605c77 ] 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 Signed-off-by: Arnd Bergmann Cc: Alexander Shishkin Cc: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170719125310.2487451-2-arnd@arndb.de Link: https://patchwork.kernel.org/patch/9392595/ Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- arch/x86/kernel/cpu/perf_event.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 83f33a2e662f..904b31ebc419 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -187,8 +187,8 @@ 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;