diff options
| -rw-r--r-- | arch/x86/include/asm/traps.h | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/traps.c | 6 | ||||
| -rw-r--r-- | arch/x86/mm/fault.c | 32 |
3 files changed, 41 insertions, 3 deletions
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index c3496619740a..01fd0a7f48cd 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -117,6 +117,12 @@ extern void ist_exit(struct pt_regs *regs); extern void ist_begin_non_atomic(struct pt_regs *regs); extern void ist_end_non_atomic(void); +#ifdef CONFIG_VMAP_STACK +void __noreturn handle_stack_overflow(const char *message, + struct pt_regs *regs, + unsigned long fault_address); +#endif + /* Interrupts/Exceptions */ enum { X86_TRAP_DE = 0, /* 0, Divide-by-zero */ diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 907b4e4aeb5e..bd4e3d4d3625 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -293,9 +293,9 @@ DO_ERROR(X86_TRAP_SS, SIGBUS, "stack segment", stack_segment) DO_ERROR(X86_TRAP_AC, SIGBUS, "alignment check", alignment_check) #ifdef CONFIG_VMAP_STACK -static void __noreturn handle_stack_overflow(const char *message, - struct pt_regs *regs, - unsigned long fault_address) +__visible void __noreturn handle_stack_overflow(const char *message, + struct pt_regs *regs, + unsigned long fault_address) { printk(KERN_EMERG "BUG: stack guard page was hit at %p (stack is %p..%p)\n", (void *)fault_address, current->stack, diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index dc8023060456..0b92fce3e6c0 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -753,6 +753,38 @@ no_context(struct pt_regs *regs, unsigned long error_code, return; } +#ifdef CONFIG_VMAP_STACK + /* + * Stack overflow? During boot, we can fault near the initial + * stack in the direct map, but that's not an overflow -- check + * that we're in vmalloc space to avoid this. + */ + if (is_vmalloc_addr((void *)address) && + (((unsigned long)tsk->stack - 1 - address < PAGE_SIZE) || + address - ((unsigned long)tsk->stack + THREAD_SIZE) < PAGE_SIZE)) { + register void *__sp asm("rsp"); + unsigned long stack = this_cpu_read(orig_ist.ist[DOUBLEFAULT_STACK]) - sizeof(void *); + /* + * We're likely to be running with very little stack space + * left. It's plausible that we'd hit this condition but + * double-fault even before we get this far, in which case + * we're fine: the double-fault handler will deal with it. + * + * We don't want to make it all the way into the oops code + * and then double-fault, though, because we're likely to + * break the console driver and lose most of the stack dump. + */ + asm volatile ("movq %[stack], %%rsp\n\t" + "call handle_stack_overflow\n\t" + "1: jmp 1b" + : "+r" (__sp) + : "D" ("kernel stack overflow (page fault)"), + "S" (regs), "d" (address), + [stack] "rm" (stack)); + unreachable(); + } +#endif + /* * 32-bit: * |