* stack checking (2/3)
- use gcc's profiling features to check for stack overflows upon
entry to functions.
- Warn if the task goes over 4k.
- Panic if the stack gets within 512 bytes of overflowing.
-- Dave Hansen haveblue@us.ibm.com
# 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 1.851 -> 1.852 # arch/i386/kernel/process.c 1.32 -> 1.33 # arch/i386/Config.help 1.21 -> 1.22 # Makefile 1.320 -> 1.321 # arch/i386/kernel/entry.S 1.38 -> 1.39 # arch/i386/config.in 1.56 -> 1.57 # arch/i386/Makefile 1.21 -> 1.22 # arch/i386/boot/compressed/misc.c 1.9 -> 1.10 # arch/i386/kernel/init_task.c 1.6 -> 1.7 # arch/i386/kernel/i386_ksyms.c 1.34 -> 1.35 # # The following is the BitKeeper ChangeSet Log # -------------------------------------------- # 02/10/14 haveblue@elm3b96.(none) 1.852 # stack_usage_check-2.5.42+bk-1.patch # -------------------------------------------- # diff -Nru a/Makefile b/Makefile --- a/Makefile Mon Oct 14 19:54:47 2002 +++ b/Makefile Mon Oct 14 19:54:47 2002 @@ -156,7 +156,8 @@ CPPFLAGS := -D__KERNEL__ -Iinclude CFLAGS := $(CPPFLAGS) -Wall -Wstrict-prototypes -Wno-trigraphs -O2 \ - -fomit-frame-pointer -fno-strict-aliasing -fno-common + -fno-strict-aliasing -fno-common + AFLAGS := -D__ASSEMBLY__ $(CPPFLAGS) export VERSION PATCHLEVEL SUBLEVEL EXTRAVERSION KERNELRELEASE ARCH \ @@ -255,6 +256,10 @@ ifdef CONFIG_MODULES export EXPORT_FLAGS := -DEXPORT_SYMTAB +endif + +ifneq ($(CONFIG_FRAME_POINTER),y) +CFLAGS += -fomit-frame-pointer endif # diff -Nru a/arch/i386/Config.help b/arch/i386/Config.help --- a/arch/i386/Config.help Mon Oct 14 19:54:47 2002 +++ b/arch/i386/Config.help Mon Oct 14 19:54:47 2002 @@ -1044,6 +1044,10 @@ symbolic stack backtraces. This increases the size of the kernel somewhat, as all symbols have to be loaded into the kernel image. +CONFIG_X86_STACK_CHECK + Say Y here to have the kernel attempt to detect when the per-task + kernel stack overflows. + CONFIG_DEBUG_OBSOLETE Say Y here if you want to reduce the chances of the tree compiling, and are prepared to dig into driver internals to fix compile errors. diff -Nru a/arch/i386/Makefile b/arch/i386/Makefile --- a/arch/i386/Makefile Mon Oct 14 19:54:47 2002 +++ b/arch/i386/Makefile Mon Oct 14 19:54:47 2002 @@ -49,6 +49,10 @@ 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 Mon Oct 14 19:54:47 2002 +++ b/arch/i386/boot/compressed/misc.c Mon Oct 14 19:54:47 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/config.in b/arch/i386/config.in --- a/arch/i386/config.in Mon Oct 14 19:54:47 2002 +++ b/arch/i386/config.in Mon Oct 14 19:54:47 2002 @@ -458,6 +458,11 @@ bool ' Highmem debugging' CONFIG_DEBUG_HIGHMEM fi bool ' Load all symbols for debugging/kksymoops' CONFIG_KALLSYMS + bool ' Check for stack overflows' CONFIG_X86_STACK_CHECK + if [ "$CONFIG_X86_STACK_CHECK" = "y" ]; then + define_bool CONFIG_FRAME_POINTER y + fi + fi if [ "$CONFIG_X86_LOCAL_APIC" = "y" ]; then diff -Nru a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S --- a/arch/i386/kernel/entry.S Mon Oct 14 19:54:47 2002 +++ b/arch/i386/kernel/entry.S Mon Oct 14 19:54:47 2002 @@ -481,6 +481,67 @@ 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 $0x200,%eax /* 512 byte danger zone */ + jle 1f /* this wil panic */ + cmpl $0x1000,%eax /* 4k stack would have overflowed */ + jle 2f /* this will just warn */ +3: + popl %eax + ret +2: + call stack_overflow_warn + jc 3b +1: + lock; btsl $0,stack_overflowed /* Prevent reentry via printk */ + jc 3b + + # 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 + + # never neverland + call stack_overflow_panic + + addl $8,%esp + + popf + popl %eax + movl %eax,%esp + popl %eax + movl $0,stack_overflowed + ret + +#warning stack check enabled +#endif + .data ENTRY(sys_call_table) .long sys_ni_syscall /* 0 - old "setup()" system call*/ diff -Nru a/arch/i386/kernel/i386_ksyms.c b/arch/i386/kernel/i386_ksyms.c --- a/arch/i386/kernel/i386_ksyms.c Mon Oct 14 19:54:47 2002 +++ b/arch/i386/kernel/i386_ksyms.c Mon Oct 14 19:54:47 2002 @@ -182,3 +182,8 @@ EXPORT_SYMBOL(is_sony_vaio_laptop); EXPORT_SYMBOL(__PAGE_KERNEL); + +#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 Mon Oct 14 19:54:47 2002 +++ b/arch/i386/kernel/init_task.c Mon Oct 14 19:54:47 2002 @@ -13,6 +13,11 @@ static struct signal_struct init_signals = INIT_SIGNALS(init_signals); struct mm_struct init_mm = INIT_MM(init_mm); +#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 Mon Oct 14 19:54:47 2002 +++ b/arch/i386/kernel/process.c Mon Oct 14 19:54:47 2002 @@ -156,7 +156,21 @@ __setup("idle=", idle_setup); -void show_regs(struct pt_regs * regs) +void stack_overflow_warn(void *esp, unsigned long eip) +{ + print_symbol("excessive stack use from %s\n", eip); + printk("esp: %p\n", esp); + show_trace(esp); +} + +void stack_overflow_panic(void *esp, void *eip) +{ + printk("stack overflow from %p. esp: %p\n", eip, esp); + show_trace(esp); + panic("stack overflow\n"); +} + +asmlinkage void show_regs(struct pt_regs * regs) { unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
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This archive was generated by hypermail 2b29 : Tue Oct 15 2002 - 22:00:53 EST