| Message ID | 20190709183612.2693974-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | mm/kasan: fix kasan_check_read() compiler warning | expand |
On Tue, 9 Jul 2019 at 20:36, Arnd Bergmann <arnd@arndb.de> wrote: > > The kasan_check_read() is marked 'inline', which usually includes > the 'always_inline' attribute. In some configuration, gcc decides that > it cannot inline this, causing a build failure: > > In file included from include/linux/compiler.h:257, > from arch/x86/include/asm/current.h:5, > from include/linux/sched.h:12, > from include/linux/ratelimit.h:6, > from fs/dcache.c:18: > include/linux/compiler.h: In function 'read_word_at_a_time': > include/linux/kasan-checks.h:31:20: error: inlining failed in call to always_inline 'kasan_check_read': function attribute mismatch > static inline bool kasan_check_read(const volatile void *p, unsigned int size) > ^~~~~~~~~~~~~~~~ > In file included from arch/x86/include/asm/current.h:5, > from include/linux/sched.h:12, > from include/linux/ratelimit.h:6, > from fs/dcache.c:18: > include/linux/compiler.h:280:2: note: called from here > kasan_check_read(addr, 1); > ^~~~~~~~~~~~~~~~~~~~~~~~~ > > While I have no idea why it does this, but changing the call to the > internal __kasan_check_read() fixes the issue. Thanks, this was fixed more generally in v5: http://lkml.kernel.org/r/20190708170706.174189-1-elver@google.com > > Fixes: dc55b51f312c ("mm/kasan: introduce __kasan_check_{read,write}") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > include/linux/compiler.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/compiler.h b/include/linux/compiler.h > index f0fd5636fddb..22909500ba1d 100644 > --- a/include/linux/compiler.h > +++ b/include/linux/compiler.h > @@ -277,7 +277,7 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s > static __no_kasan_or_inline > unsigned long read_word_at_a_time(const void *addr) > { > - kasan_check_read(addr, 1); > + __kasan_check_read(addr, 1); > return *(unsigned long *)addr; > } > > -- > 2.20.0 >
On Tue, Jul 9, 2019 at 11:36 AM Arnd Bergmann <arnd@arndb.de> wrote: > > The kasan_check_read() is marked 'inline', which usually includes > the 'always_inline' attribute. In some configuration, gcc decides that > it cannot inline this, causing a build failure: > > In file included from include/linux/compiler.h:257, > from arch/x86/include/asm/current.h:5, > from include/linux/sched.h:12, > from include/linux/ratelimit.h:6, > from fs/dcache.c:18: > include/linux/compiler.h: In function 'read_word_at_a_time': > include/linux/kasan-checks.h:31:20: error: inlining failed in call to always_inline 'kasan_check_read': function attribute mismatch Sounds like the error `function attribute mismatch` is saying: kasan_check_read has one set of function attributes, but the call site read_word_at_a_time has different function attributes, so I wont inline kasan_check_read into read_word_at_a_time. __no_kasan_or_inline changes based on CONFIG_KASAN; was this from a kasan build or not? > static inline bool kasan_check_read(const volatile void *p, unsigned int size) > ^~~~~~~~~~~~~~~~ > In file included from arch/x86/include/asm/current.h:5, > from include/linux/sched.h:12, > from include/linux/ratelimit.h:6, > from fs/dcache.c:18: > include/linux/compiler.h:280:2: note: called from here > kasan_check_read(addr, 1); > ^~~~~~~~~~~~~~~~~~~~~~~~~ > > While I have no idea why it does this, but changing the call to the > internal __kasan_check_read() fixes the issue. > > Fixes: dc55b51f312c ("mm/kasan: introduce __kasan_check_{read,write}") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > include/linux/compiler.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/compiler.h b/include/linux/compiler.h > index f0fd5636fddb..22909500ba1d 100644 > --- a/include/linux/compiler.h > +++ b/include/linux/compiler.h > @@ -277,7 +277,7 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s > static __no_kasan_or_inline > unsigned long read_word_at_a_time(const void *addr) > { > - kasan_check_read(addr, 1); > + __kasan_check_read(addr, 1); > return *(unsigned long *)addr; > } > > -- > 2.20.0 > -- Thanks, ~Nick Desaulniers
On Tue, Jul 9, 2019 at 8:46 PM Marco Elver <elver@google.com> wrote: > > On Tue, 9 Jul 2019 at 20:36, Arnd Bergmann <arnd@arndb.de> wrote: > > > > The kasan_check_read() is marked 'inline', which usually includes > > the 'always_inline' attribute. In some configuration, gcc decides that > > it cannot inline this, causing a build failure: > > > > In file included from include/linux/compiler.h:257, > > from arch/x86/include/asm/current.h:5, > > from include/linux/sched.h:12, > > from include/linux/ratelimit.h:6, > > from fs/dcache.c:18: > > include/linux/compiler.h: In function 'read_word_at_a_time': > > include/linux/kasan-checks.h:31:20: error: inlining failed in call to always_inline 'kasan_check_read': function attribute mismatch > > static inline bool kasan_check_read(const volatile void *p, unsigned int size) > > ^~~~~~~~~~~~~~~~ > > In file included from arch/x86/include/asm/current.h:5, > > from include/linux/sched.h:12, > > from include/linux/ratelimit.h:6, > > from fs/dcache.c:18: > > include/linux/compiler.h:280:2: note: called from here > > kasan_check_read(addr, 1); > > ^~~~~~~~~~~~~~~~~~~~~~~~~ > > > > While I have no idea why it does this, but changing the call to the > > internal __kasan_check_read() fixes the issue. > > Thanks, this was fixed more generally in v5: > http://lkml.kernel.org/r/20190708170706.174189-1-elver@google.com Ok, that looks like a better solution indeed. I tried something similar at first but got it wrong. Arnd
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index f0fd5636fddb..22909500ba1d 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -277,7 +277,7 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s static __no_kasan_or_inline unsigned long read_word_at_a_time(const void *addr) { - kasan_check_read(addr, 1); + __kasan_check_read(addr, 1); return *(unsigned long *)addr; }
The kasan_check_read() is marked 'inline', which usually includes the 'always_inline' attribute. In some configuration, gcc decides that it cannot inline this, causing a build failure: In file included from include/linux/compiler.h:257, from arch/x86/include/asm/current.h:5, from include/linux/sched.h:12, from include/linux/ratelimit.h:6, from fs/dcache.c:18: include/linux/compiler.h: In function 'read_word_at_a_time': include/linux/kasan-checks.h:31:20: error: inlining failed in call to always_inline 'kasan_check_read': function attribute mismatch static inline bool kasan_check_read(const volatile void *p, unsigned int size) ^~~~~~~~~~~~~~~~ In file included from arch/x86/include/asm/current.h:5, from include/linux/sched.h:12, from include/linux/ratelimit.h:6, from fs/dcache.c:18: include/linux/compiler.h:280:2: note: called from here kasan_check_read(addr, 1); ^~~~~~~~~~~~~~~~~~~~~~~~~ While I have no idea why it does this, but changing the call to the internal __kasan_check_read() fixes the issue. Fixes: dc55b51f312c ("mm/kasan: introduce __kasan_check_{read,write}") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- include/linux/compiler.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.20.0