C-stack_usage_check-2.5.52+bk-6.patch
Check for stack overflows on entry to each funtion. Use gcc's
-p profiling feature to do it.
-- Dave Hansen haveblue@us.ibm.com
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# This is a BitKeeper generated patch for the following project: # Project Name: Linux kernel tree # This patch format is intended for GNU patch command version 2.5 or higher. # This patch includes the following deltas: # ChangeSet 1.860.1.2 -> 1.866 # arch/i386/kernel/process.c 1.32.1.3 -> 1.38 # arch/i386/kernel/irq.c 1.23.1.2 -> 1.26 # Makefile 1.344 -> 1.346 # include/asm-i386/thread_info.h 1.10.1.2 -> 1.14 # arch/i386/Kconfig 1.13 -> 1.15 # arch/i386/kernel/entry.S 1.38.1.6 -> 1.49 # arch/i386/Makefile 1.24.2.7 -> 1.30 # arch/i386/boot/compressed/misc.c 1.9 -> 1.10 # arch/i386/kernel/init_task.c 1.6.1.1 -> 1.8 # arch/i386/kernel/i386_ksyms.c 1.36.2.4 -> 1.41 # # The following is the BitKeeper ChangeSet Log # -------------------------------------------- # 02/12/15 haveblue@elm3b96.(none) 1.859.1.2 # Merge elm3b96.(none):/work/dave/bk/linux-2.5-thread_info_infra # into elm3b96.(none):/work/dave/bk/linux-2.5-overflow-detect # -------------------------------------------- # 02/12/15 haveblue@elm3b96.(none) 1.865 # Merge elm3b96.(none):/work/dave/bk/linux-2.5-irq-stack # into elm3b96.(none):/work/dave/bk/linux-2.5-irq-stack+overflow-detect # -------------------------------------------- # 02/12/15 haveblue@elm3b96.(none) 1.866 # Merge elm3b96.(none):/work/dave/bk/linux-2.5-overflow-detect # into elm3b96.(none):/work/dave/bk/linux-2.5-irq-stack+overflow-detect # -------------------------------------------- # diff -Nru a/arch/i386/Kconfig b/arch/i386/Kconfig --- a/arch/i386/Kconfig Sun Dec 15 21:16:27 2002 +++ b/arch/i386/Kconfig Sun Dec 15 21:16:27 2002 @@ -1573,6 +1573,25 @@ 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 diff -Nru a/arch/i386/Makefile b/arch/i386/Makefile --- a/arch/i386/Makefile Sun Dec 15 21:16:27 2002 +++ b/arch/i386/Makefile Sun Dec 15 21:16:27 2002 @@ -52,6 +52,10 @@ MACHINE := mach-generic endif +ifdef CONFIG_X86_STACK_CHECK +CFLAGS += -p +endif + HEAD := arch/i386/kernel/head.o arch/i386/kernel/init_task.o libs-y += arch/i386/lib/ diff -Nru a/arch/i386/boot/compressed/misc.c b/arch/i386/boot/compressed/misc.c --- a/arch/i386/boot/compressed/misc.c Sun Dec 15 21:16:27 2002 +++ b/arch/i386/boot/compressed/misc.c Sun Dec 15 21:16:27 2002 @@ -377,3 +377,7 @@ 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 -Nru a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S --- a/arch/i386/kernel/entry.S Sun Dec 15 21:16:27 2002 +++ b/arch/i386/kernel/entry.S Sun Dec 15 21:16:27 2002 @@ -520,6 +520,61 @@ 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 -Nru a/arch/i386/kernel/i386_ksyms.c b/arch/i386/kernel/i386_ksyms.c --- a/arch/i386/kernel/i386_ksyms.c Sun Dec 15 21:16:27 2002 +++ b/arch/i386/kernel/i386_ksyms.c Sun Dec 15 21:16:27 2002 @@ -216,3 +216,8 @@ EXPORT_SYMBOL(edd); EXPORT_SYMBOL(eddnr); #endif + +#ifdef CONFIG_X86_STACK_CHECK +extern void mcount(void); +EXPORT_SYMBOL(mcount); +#endif diff -Nru a/arch/i386/kernel/init_task.c b/arch/i386/kernel/init_task.c --- a/arch/i386/kernel/init_task.c Sun Dec 15 21:16:27 2002 +++ b/arch/i386/kernel/init_task.c Sun Dec 15 21:16:27 2002 @@ -16,6 +16,10 @@ 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 -Nru a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c --- a/arch/i386/kernel/process.c Sun Dec 15 21:16:27 2002 +++ b/arch/i386/kernel/process.c Sun Dec 15 21:16:27 2002 @@ -158,7 +158,25 @@ __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%x masked: 0x%x 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 -Nru a/include/asm-i386/thread_info.h b/include/asm-i386/thread_info.h --- a/include/asm-i386/thread_info.h Sun Dec 15 21:16:27 2002 +++ b/include/asm-i386/thread_info.h Sun Dec 15 21:16:27 2002 @@ -63,6 +63,8 @@ */ #define THREAD_ORDER 1 #define INIT_THREAD_SIZE THREAD_SIZE +#define STACK_PANIC 0x200ul +#define STACK_WARN ((THREAD_SIZE)>>1) #ifndef __ASSEMBLY__
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