fatal() never returns, but compilers are not aware of this fact because
exit(1) is called within the modpost_log() definition.
Move exit(1) to the fatal() macro so that compilers can identify
unreachable code flows.
Remove the initializer for 'taddr' in section_rel(), as compilers now
recognize this is not an uninitialized bug.
Signed-off-by: Masahiro Yamada <[email protected]>
---
scripts/mod/modpost.c | 4 +---
scripts/mod/modpost.h | 2 +-
2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 013fc5031bc7..696c583a14ec 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -84,8 +84,6 @@ void modpost_log(enum loglevel loglevel, const char *fmt, ...)
vfprintf(stderr, fmt, arglist);
va_end(arglist);
- if (loglevel == LOG_FATAL)
- exit(1);
if (loglevel == LOG_ERROR)
error_occurred = true;
}
@@ -1415,7 +1413,7 @@ static void section_rel(struct module *mod, struct elf_info *elf,
for (rel = start; rel < stop; rel++) {
Elf_Sym *tsym;
- Elf_Addr taddr = 0, r_offset;
+ Elf_Addr taddr, r_offset;
unsigned int r_type, r_sym;
void *loc;
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 9fe974dc1a52..aaa67b24775e 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -215,4 +215,4 @@ modpost_log(enum loglevel loglevel, const char *fmt, ...);
*/
#define warn(fmt, args...) modpost_log(LOG_WARN, fmt, ##args)
#define error(fmt, args...) modpost_log(LOG_ERROR, fmt, ##args)
-#define fatal(fmt, args...) modpost_log(LOG_FATAL, fmt, ##args)
+#define fatal(fmt, args...) do { modpost_log(LOG_FATAL, fmt, ##args); exit(1); } while (1)
--
2.40.1
On Sat, Nov 25, 2023 at 07:31:16PM +0900, Masahiro Yamada wrote:
> fatal() never returns, but compilers are not aware of this fact because
> exit(1) is called within the modpost_log() definition.
>
> Move exit(1) to the fatal() macro so that compilers can identify
> unreachable code flows.
>
> Remove the initializer for 'taddr' in section_rel(), as compilers now
> recognize this is not an uninitialized bug.
>
> Signed-off-by: Masahiro Yamada <[email protected]>
While I did not see any warnings when testing, it seems like this patch
should come before patch 2 to avoid any potential problems from dropping
the unreachable code (since the compiler won't be able to infer that
fatal() is __noreturn without this change); doesn't really matter though
so:
Reviewed-by: Nathan Chancellor <[email protected]>
> ---
>
> scripts/mod/modpost.c | 4 +---
> scripts/mod/modpost.h | 2 +-
> 2 files changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index 013fc5031bc7..696c583a14ec 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -84,8 +84,6 @@ void modpost_log(enum loglevel loglevel, const char *fmt, ...)
> vfprintf(stderr, fmt, arglist);
> va_end(arglist);
>
> - if (loglevel == LOG_FATAL)
> - exit(1);
> if (loglevel == LOG_ERROR)
> error_occurred = true;
> }
> @@ -1415,7 +1413,7 @@ static void section_rel(struct module *mod, struct elf_info *elf,
>
> for (rel = start; rel < stop; rel++) {
> Elf_Sym *tsym;
> - Elf_Addr taddr = 0, r_offset;
> + Elf_Addr taddr, r_offset;
> unsigned int r_type, r_sym;
> void *loc;
>
> diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
> index 9fe974dc1a52..aaa67b24775e 100644
> --- a/scripts/mod/modpost.h
> +++ b/scripts/mod/modpost.h
> @@ -215,4 +215,4 @@ modpost_log(enum loglevel loglevel, const char *fmt, ...);
> */
> #define warn(fmt, args...) modpost_log(LOG_WARN, fmt, ##args)
> #define error(fmt, args...) modpost_log(LOG_ERROR, fmt, ##args)
> -#define fatal(fmt, args...) modpost_log(LOG_FATAL, fmt, ##args)
> +#define fatal(fmt, args...) do { modpost_log(LOG_FATAL, fmt, ##args); exit(1); } while (1)
> --
> 2.40.1
>
On Thu, Nov 30, 2023 at 9:32 AM Nathan Chancellor <[email protected]> wrote:
>
> On Sat, Nov 25, 2023 at 07:31:16PM +0900, Masahiro Yamada wrote:
> > fatal() never returns, but compilers are not aware of this fact because
> > exit(1) is called within the modpost_log() definition.
> >
> > Move exit(1) to the fatal() macro so that compilers can identify
> > unreachable code flows.
> >
> > Remove the initializer for 'taddr' in section_rel(), as compilers now
> > recognize this is not an uninitialized bug.
> >
> > Signed-off-by: Masahiro Yamada <[email protected]>
>
> While I did not see any warnings when testing, it seems like this patch
> should come before patch 2 to avoid any potential problems from dropping
> the unreachable code (since the compiler won't be able to infer that
> fatal() is __noreturn without this change); doesn't really matter though
> so:
My eyes spotted 2/3, but I can swap the patch order
and rephase the patch description because clang can
detect the unreachable code.
> Reviewed-by: Nathan Chancellor <[email protected]>
>
> > ---
> >
> > scripts/mod/modpost.c | 4 +---
> > scripts/mod/modpost.h | 2 +-
> > 2 files changed, 2 insertions(+), 4 deletions(-)
> >
> > diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> > index 013fc5031bc7..696c583a14ec 100644
> > --- a/scripts/mod/modpost.c
> > +++ b/scripts/mod/modpost.c
> > @@ -84,8 +84,6 @@ void modpost_log(enum loglevel loglevel, const char *fmt, ...)
> > vfprintf(stderr, fmt, arglist);
> > va_end(arglist);
> >
> > - if (loglevel == LOG_FATAL)
> > - exit(1);
> > if (loglevel == LOG_ERROR)
> > error_occurred = true;
> > }
> > @@ -1415,7 +1413,7 @@ static void section_rel(struct module *mod, struct elf_info *elf,
> >
> > for (rel = start; rel < stop; rel++) {
> > Elf_Sym *tsym;
> > - Elf_Addr taddr = 0, r_offset;
> > + Elf_Addr taddr, r_offset;
> > unsigned int r_type, r_sym;
> > void *loc;
> >
> > diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
> > index 9fe974dc1a52..aaa67b24775e 100644
> > --- a/scripts/mod/modpost.h
> > +++ b/scripts/mod/modpost.h
> > @@ -215,4 +215,4 @@ modpost_log(enum loglevel loglevel, const char *fmt, ...);
> > */
> > #define warn(fmt, args...) modpost_log(LOG_WARN, fmt, ##args)
> > #define error(fmt, args...) modpost_log(LOG_ERROR, fmt, ##args)
> > -#define fatal(fmt, args...) modpost_log(LOG_FATAL, fmt, ##args)
> > +#define fatal(fmt, args...) do { modpost_log(LOG_FATAL, fmt, ##args); exit(1); } while (1)
> > --
> > 2.40.1
> >
>
--
Best Regards
Masahiro Yamada