queue-4.9/x86-hw_breakpoints-make-default-case-in-hw_breakpoin.patch

   1 From d6c90d2921b07a73ef87208967b0b7f7c5fdb886 Mon Sep 17 00:00:00 2001
   2 From: Nathan Chancellor <natechancellor@gmail.com>
   3 Date: Thu, 7 Mar 2019 14:27:56 -0700
   4 Subject: x86/hw_breakpoints: Make default case in hw_breakpoint_arch_parse()
   5  return an error
   6
   7 [ Upstream commit e898e69d6b9475bf123f99b3c5d1a67bb7cb2361 ]
   8
   9 When building with -Wsometimes-uninitialized, Clang warns:
  10
  11 arch/x86/kernel/hw_breakpoint.c:355:2: warning: variable 'align' is used
  12 uninitialized whenever switch default is taken
  13 [-Wsometimes-uninitialized]
  14
  15 The default cannot be reached because arch_build_bp_info() initializes
  16 hw->len to one of the specified cases. Nevertheless the warning is valid
  17 and returning -EINVAL makes sure that this cannot be broken by future
  18 modifications.
  19
  20 Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
  21 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
  22 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  23 Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
  24 Cc: Borislav Petkov <bp@alien8.de>
  25 Cc: "H. Peter Anvin" <hpa@zytor.com>
  26 Cc: clang-built-linux@googlegroups.com
  27 Link: https://github.com/ClangBuiltLinux/linux/issues/392
  28 Link: https://lkml.kernel.org/r/20190307212756.4648-1-natechancellor@gmail.com
  29 Signed-off-by: Sasha Levin <sashal@kernel.org>
  30 ---
  31  arch/x86/kernel/hw_breakpoint.c | 1 +
  32  1 file changed, 1 insertion(+)
  33
  34 diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
  35 index 8771766d46b6..9954a604a822 100644
  36 --- a/arch/x86/kernel/hw_breakpoint.c
  37 +++ b/arch/x86/kernel/hw_breakpoint.c
  38 @@ -352,6 +352,7 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
  39  #endif
  40         default:
  41                 WARN_ON_ONCE(1);
  42 +               return -EINVAL;
  43         }
  44
  45         /*
  46 --
  47 2.19.1
  48