gcc 4.1.0 and 4.1.1 are known to miscompile the kernel:

  http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
Usage of weak functions has become a common pattern in the kernel, and

usages get added in each kernel version increasing the probability of

bugs with each kernel release.
This miscompilation of weak functions can result in subtle runtime

errors.
#error for gcc 4.1.0 and 4.1.1 to prevent users from running into

this bug.
Note:

We already printed a #warning for gcc 4.1.0 due to a different bug.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
---
This patch has been sent on:

- 6 Aug 2008

- 26 Jun 2008
ee78871a1d85fe60958748c208389adb4031fefe diff --git a/init/main.c b/init/main.c

index f7fb200..bede344 100644

--- a/init/main.c

+++ b/init/main.c

@@ -76,8 +76,9 @@

  * trouble.

  */
-#if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0

-#warning gcc-4.1.0 is known to miscompile the kernel.  A different compiler version is recommended.

+/*  due to http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781  */

+#if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && (__GNUC_PATCHLEVEL__ == 0 || __GNUC_PATCHLEVEL__ == 1)

+#error gcc 4.1.0 and 4.1.1 are known to miscompile the kernel.

 #endif
 static int kernel_init(void *);
--

On Wed, 13 Aug 2008 23:44:45 +0300
I've been hiding from this because it would wreck a lot of my

cross-compilers, which quite a few other people are using as well.
Vegard, save us!

--

We are talking about runtime breakages, with new breakages added in each

kernel release.
Which is not nice for users.
And my patch is the result of developers spending time on debugging and

working around a real-life bug caused by this compiler bug.
If you insist on keeping your 4.1.0 compilers I can prepare a patch that 
cu

Adrian
-- 
       "Is there not promise of rain?" Ling Tan asked suddenly out

        of the darkness. There had been need of rain for many days.

       "Only a promise," Lao Er said.

                                       Pearl S. Buck - Dragon Seed
--