Messages in this thread Patch in this message | | | Date | Fri, 26 Dec 2008 16:33:18 +0100 | From | Ingo Molnar <> | Subject | Re: [BUG] next-20081216 - WARNING: at kernel/smp.c:333 smp_call_function_mask |
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* Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> wrote:
> * Sam Ravnborg <sam@ravnborg.org> [2008-12-26 11:27:16]: > > > On Fri, Dec 26, 2008 at 02:05:47AM -0800, Yinghai Lu wrote: > > > Kamalesh Babulal wrote: > > > > * Yinghai Lu <yinghai@kernel.org> [2008-12-24 12:34:41]: > > > > > > > >> -- > > > > > > > > After the applying the patch, the kernel panic's with the same backtrace. The > > > > box is running Fedora 5 on it. > > > > > > > > > > please try... > > > Ingo, do we need to switch to use #idef and inline function instead? > > > > I recall David Howells had a similar issue with the bootparamter patch set. > > The workaround he used was to add a barrier(); call in the weak function > > to avoid the inline. > > > > [full context kept as I added David to to: list]. > > Sam > > > > Hi Yinghai, > > Thanks, after applying the patch, the kernel boot's up fine.
how about the patch below, does that work too? (after removing Yinghai's patch)
Ingo
-------------> From 0d41e654c877a0de441448ca2f63a72ed11c5d84 Mon Sep 17 00:00:00 2001 From: Ingo Molnar <mingo@elte.hu> Date: Fri, 26 Dec 2008 14:39:51 +0100 Subject: [PATCH] kbuild, sparseirq: work around GCC bug with __weak aliases
Impact: fix panic on null pointer with sparseirq
Certain versions of GCC inline the weak global functions. Work it around by marking __weak functions as noinline.
Signed-off-by: Ingo Molnar <mingo@elte.hu> --- include/linux/compiler-gcc.h | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 5c8351b..1ad72e6 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -41,11 +41,17 @@ #define __deprecated __attribute__((deprecated)) #define __packed __attribute__((packed)) -#define __weak __attribute__((weak)) #define __naked __attribute__((naked)) #define __noreturn __attribute__((noreturn)) /* + * Mark weak aliases also noinline, because some GCC versions + * incorrectly inline weak aliases (even when a non-weak variant + * is there) and thus cause crashes: + */ +#define __weak __attribute__((weak)) noinline + +/* * From the GCC manual: * * Many functions have no effects except the return value and their
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