From: Dave Hansen Investigation of why the build is failing due to bogus detection of undefined symbols: We're getting this warning: arch/i386/kernel/irq.c {standard input}: Assembler messages: {standard input}:3565: Warning: setting incorrect section type for .bss.page_aligned Which comes from this code in the 4k stacks code: static char softirq_stack[NR_CPUS * THREAD_SIZE] __attribute__((__aligned__(THREAD_SIZE), __section__(".bss.page_aligned"))); static char hardirq_stack[NR_CPUS * THREAD_SIZE] __attribute__((__aligned__(THREAD_SIZE), __section__(".bss.page_aligned"))); Removing the __section__() fixes it, as does moving to gcc 3.2 or 3.3, but gcc 2.95 and 3.0 still exhibit the problem. It seems the 4k stack developers like newer compilers than I do :) The gcc 2.95 section declaration looks like this: .section .bss.page_aligned,"aw",@progbits while the 3.1 section looks like this: .section .bss.page_aligned,"aw",@nobits It's definitely a bug that's been fixed: http://sources.redhat.com/ml/binutils/2002-10/msg00507.html I've been told that I can fix it with a carefully crafted assembly file and maybe a change to the linker script, but all that it buys us is a little space in the uncompressed kernel image. Plus, the warning will still be there at compile-time. I say, put them back in plain old BSS. Patch attached. Signed-off-by: Andrew Morton --- 25-akpm/arch/i386/kernel/irq.c | 8 ++++++-- 1 files changed, 6 insertions(+), 2 deletions(-) diff -puN arch/i386/kernel/irq.c~268-rc2-mm1-link-errors arch/i386/kernel/irq.c --- 25/arch/i386/kernel/irq.c~268-rc2-mm1-link-errors 2004-07-28 22:11:29.652159016 -0700 +++ 25-akpm/arch/i386/kernel/irq.c 2004-07-28 22:11:29.658158104 -0700 @@ -1118,8 +1118,12 @@ void init_irq_proc (void) #ifdef CONFIG_4KSTACKS -static char softirq_stack[NR_CPUS * THREAD_SIZE] __attribute__((__aligned__(THREAD_SIZE), __section__(".bss.page_aligned"))); -static char hardirq_stack[NR_CPUS * THREAD_SIZE] __attribute__((__aligned__(THREAD_SIZE), __section__(".bss.page_aligned"))); +/* + * These should really be __section__(".bss.page_aligned") as well, but + * gcc's 3.0 and earlier don't handle that correctly. + */ +static char softirq_stack[NR_CPUS * THREAD_SIZE] __attribute__((__aligned__(THREAD_SIZE))); +static char hardirq_stack[NR_CPUS * THREAD_SIZE] __attribute__((__aligned__(THREAD_SIZE))); /* * allocate per-cpu stacks for hardirq and for softirq processing _