When CONFIG_CC_OPTIMIZE_FOR_DEBUGGING is set, we get countless warnings
like
In function 'check_copy_size',
inlined from 'copy_from_user' at include/linux/uaccess.h:146:6,
inlined from '__copy_siginfo_from_user' at kernel/signal.c:3032:6:
include/linux/thread_info.h:147:4: error: call to '__bad_copy_to' declared with
attribute error: copy destination size is too small
It seems that constant propagation doesn't work well enough to make
this code reliable, so turn it off for that configuration.
Cc: Changbin Du<changbin...@gmail.com>
Cc: Al Viro <v...@zeniv.linux.org.uk>
Signed-off-by: Arnd Bergmann <a...@arndb.de>
---
include/linux/thread_info.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index 8d8821b3689a..762f379bdf5d 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -138,6 +138,11 @@ static __always_inline bool
check_copy_size(const void *addr, size_t bytes, bool is_source)
{
int sz = __compiletime_object_size(addr);
+
+ /* constant propagation doesn't work well with -Og */
+ if (IS_ENABLED(CONFIG_CC_OPTIMIZE_FOR_DEBUGGING))
+ return true;
+
if (unlikely(sz >= 0 && sz < bytes)) {
if (!__builtin_constant_p(bytes))
copy_overflow(sz, bytes);
--
2.18.0
