x86/hw_breakpoints: Make default case in hw_breakpoint_arch_parse() return an error

nathanchance · KAGA-KOKO · commit e898e69d6b94 · 2019-03-22T17:08:17.000+01:00
When building with -Wsometimes-uninitialized, Clang warns: arch/x86/kernel/hw_breakpoint.c:355:2: warning: variable 'align' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized] The default cannot be reached because arch_build_bp_info() initializes hw->len to one of the specified cases. Nevertheless the warning is valid and returning -EINVAL makes sure that this cannot be broken by future modifications. Suggested-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: clang-built-linux@googlegroups.com Link: ClangBuiltLinux#392 Link: https://lkml.kernel.org/r/20190307212756.4648-1-natechancellor@gmail.com
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
@@ -354,6 +354,7 @@ int hw_breakpoint_arch_parse(struct perf_event *bp,
 #endif
 	default:
 		WARN_ON_ONCE(1);
+		return -EINVAL;
 	}
 
 	/*

Original file line number	Diff line number	Diff line change
`@@ -354,6 +354,7 @@ int hw_breakpoint_arch_parse(struct perf_event *bp,`
`354`	`354`	`#endif`
`355`	`355`	`default:`
`356`	`356`	`WARN_ON_ONCE(1);`
	`357`	`+ return -EINVAL;`
`357`	`358`	`}`
`358`	`359`
`359`	`360`	`/*`