diff -urpN -X /home/fletch/.diff.exclude 221-interrupt_stacks/arch/i386/Kconfig 222-stack_usage_check/arch/i386/Kconfig
--- 221-interrupt_stacks/arch/i386/Kconfig Wed Jun 18 21:49:24 2003
+++ 222-stack_usage_check/arch/i386/Kconfig Wed Jun 18 21:49:26 2003
@@ -1594,6 +1594,25 @@ config FRAME_POINTER
If you don't debug the kernel, you can say N, but we may not be able
to solve problems without frame pointers.
+config X86_STACK_CHECK
+ bool "Detect stack overflows"
+ depends on FRAME_POINTER
+ help
+ Say Y here to have the kernel attempt to detect when the per-task
+ kernel stack overflows. This is much more robust checking than
+ the above overflow check, which will only occasionally detect
+ an overflow. The level of guarantee here is much greater.
+
+ Some older versions of gcc don't handle the -p option correctly.
+ Kernprof is affected by the same problem, which is described here:
+ http://oss.sgi.com/projects/kernprof/faq.html#Q9
+
+ Basically, if you get oopses in __free_pages_ok during boot when
+ you have this turned on, you need to fix gcc. The Redhat 2.96
+ version and gcc-3.x seem to work.
+
+ If not debugging a stack overflow problem, say N
+
config X86_EXTRA_IRQS
bool
depends on X86_LOCAL_APIC || X86_VOYAGER
diff -urpN -X /home/fletch/.diff.exclude 221-interrupt_stacks/arch/i386/Makefile 222-stack_usage_check/arch/i386/Makefile
--- 221-interrupt_stacks/arch/i386/Makefile Wed Jun 18 21:49:12 2003
+++ 222-stack_usage_check/arch/i386/Makefile Wed Jun 18 21:49:26 2003
@@ -85,6 +85,10 @@ mcore-$(CONFIG_X86_ES7000) := mach-es700
# default subarch .h files
mflags-y += -Iinclude/asm-i386/mach-default
+ifdef CONFIG_X86_STACK_CHECK
+CFLAGS += -p
+endif
+
head-y := arch/i386/kernel/head.o arch/i386/kernel/init_task.o
libs-y += arch/i386/lib/
diff -urpN -X /home/fletch/.diff.exclude 221-interrupt_stacks/arch/i386/boot/compressed/misc.c 222-stack_usage_check/arch/i386/boot/compressed/misc.c
--- 221-interrupt_stacks/arch/i386/boot/compressed/misc.c Sun Apr 20 19:34:56 2003
+++ 222-stack_usage_check/arch/i386/boot/compressed/misc.c Wed Jun 18 21:49:26 2003
@@ -379,3 +379,7 @@ asmlinkage int decompress_kernel(struct
if (high_loaded) close_output_buffer_if_we_run_high(mv);
return high_loaded;
}
+
+/* We don't actually check for stack overflows this early. */
+__asm__(".globl mcount ; mcount: ret\n");
+
diff -urpN -X /home/fletch/.diff.exclude 221-interrupt_stacks/arch/i386/kernel/entry.S 222-stack_usage_check/arch/i386/kernel/entry.S
--- 221-interrupt_stacks/arch/i386/kernel/entry.S Wed Jun 18 21:49:24 2003
+++ 222-stack_usage_check/arch/i386/kernel/entry.S Wed Jun 18 21:49:26 2003
@@ -690,6 +690,61 @@ ENTRY(spurious_interrupt_bug)
pushl $do_spurious_interrupt_bug
jmp error_code
+
+#ifdef CONFIG_X86_STACK_CHECK
+.data
+ .globl stack_overflowed
+stack_overflowed:
+ .long 0
+.text
+
+ENTRY(mcount)
+ push %eax
+ movl $(THREAD_SIZE - 1),%eax
+ andl %esp,%eax
+ cmpl $STACK_WARN,%eax /* more than half the stack is used*/
+ jle 1f
+2:
+ popl %eax
+ ret
+1:
+ lock; btsl $0,stack_overflowed
+ jc 2b
+
+ # switch to overflow stack
+ movl %esp,%eax
+ movl $(stack_overflow_stack + THREAD_SIZE - 4),%esp
+
+ pushf
+ cli
+ pushl %eax
+
+ # push eip then esp of error for stack_overflow_panic
+ pushl 4(%eax)
+ pushl %eax
+
+ # update the task pointer and cpu in the overflow stack's thread_info.
+ GET_THREAD_INFO_WITH_ESP(%eax)
+ movl TI_TASK(%eax),%ebx
+ movl %ebx,stack_overflow_stack+TI_TASK
+ movl TI_CPU(%eax),%ebx
+ movl %ebx,stack_overflow_stack+TI_CPU
+
+ call stack_overflow
+
+ # pop off call arguments
+ addl $8,%esp
+
+ popl %eax
+ popf
+ movl %eax,%esp
+ popl %eax
+ movl $0,stack_overflowed
+ ret
+
+#warning stack check enabled
+#endif
+
.data
ENTRY(sys_call_table)
.long sys_restart_syscall /* 0 - old "setup()" system call, used for restarting */
diff -urpN -X /home/fletch/.diff.exclude 221-interrupt_stacks/arch/i386/kernel/i386_ksyms.c 222-stack_usage_check/arch/i386/kernel/i386_ksyms.c
--- 221-interrupt_stacks/arch/i386/kernel/i386_ksyms.c Wed Jun 18 21:49:21 2003
+++ 222-stack_usage_check/arch/i386/kernel/i386_ksyms.c Wed Jun 18 21:49:26 2003
@@ -222,3 +222,8 @@ EXPORT_SYMBOL(kmap_atomic_to_page);
EXPORT_SYMBOL(edd);
EXPORT_SYMBOL(eddnr);
#endif
+
+#ifdef CONFIG_X86_STACK_CHECK
+extern void mcount(void);
+EXPORT_SYMBOL(mcount);
+#endif
diff -urpN -X /home/fletch/.diff.exclude 221-interrupt_stacks/arch/i386/kernel/init_task.c 222-stack_usage_check/arch/i386/kernel/init_task.c
--- 221-interrupt_stacks/arch/i386/kernel/init_task.c Wed Jun 18 21:49:24 2003
+++ 222-stack_usage_check/arch/i386/kernel/init_task.c Wed Jun 18 21:49:26 2003
@@ -17,6 +17,10 @@ struct mm_struct init_mm = INIT_MM(init_
union thread_union init_irq_union
__attribute__((__section__(".data.init_task")));
+#ifdef CONFIG_X86_STACK_CHECK
+union thread_union stack_overflow_stack
+ __attribute__((__section__(".data.init_task")));
+#endif
/*
* Initial thread structure.
diff -urpN -X /home/fletch/.diff.exclude 221-interrupt_stacks/arch/i386/kernel/process.c 222-stack_usage_check/arch/i386/kernel/process.c
--- 221-interrupt_stacks/arch/i386/kernel/process.c Wed Jun 18 21:49:25 2003
+++ 222-stack_usage_check/arch/i386/kernel/process.c Wed Jun 18 21:49:26 2003
@@ -160,7 +160,25 @@ static int __init idle_setup (char *str)
__setup("idle=", idle_setup);
-void show_regs(struct pt_regs * regs)
+void stack_overflow(unsigned long esp, unsigned long eip)
+{
+ int panicing = ((esp&(THREAD_SIZE-1)) <= STACK_PANIC);
+
+ printk( "esp: 0x%lx masked: 0x%lx STACK_PANIC:0x%x %d %d\n",
+ esp, (esp&(THREAD_SIZE-1)), STACK_PANIC, (((esp&(THREAD_SIZE-1)) <= STACK_PANIC)), panicing );
+
+ if (panicing)
+ print_symbol("stack overflow from %s\n", eip);
+ else
+ print_symbol("excessive stack use from %s\n", eip);
+ printk("esp: %p\n", (void*)esp);
+ show_trace((void*)esp);
+
+ if (panicing)
+ panic("stack overflow\n");
+}
+
+asmlinkage void show_regs(struct pt_regs * regs)
{
unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
diff -urpN -X /home/fletch/.diff.exclude 221-interrupt_stacks/include/asm-i386/thread_info.h 222-stack_usage_check/include/asm-i386/thread_info.h
--- 221-interrupt_stacks/include/asm-i386/thread_info.h Wed Jun 18 21:49:25 2003
+++ 222-stack_usage_check/include/asm-i386/thread_info.h Wed Jun 18 21:49:26 2003
@@ -65,6 +65,8 @@ struct thread_info {
*/
#define THREAD_ORDER 1
#define INIT_THREAD_SIZE THREAD_SIZE
+#define STACK_PANIC 0x200ul
+#define STACK_WARN ((THREAD_SIZE)>>1)
#ifndef __ASSEMBLY__