diff options
Diffstat (limited to 'arch/x86/mm/fault.c')
| -rw-r--r-- | arch/x86/mm/fault.c | 43 |
1 files changed, 42 insertions, 1 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index dc8023060456..4dc13340653e 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -5,7 +5,7 @@ */ #include <linux/sched.h> /* test_thread_flag(), ... */ #include <linux/kdebug.h> /* oops_begin/end, ... */ -#include <linux/module.h> /* search_exception_table */ +#include <linux/extable.h> /* search_exception_table */ #include <linux/bootmem.h> /* max_low_pfn */ #include <linux/kprobes.h> /* NOKPROBE_SYMBOL, ... */ #include <linux/mmiotrace.h> /* kmmio_handler, ... */ @@ -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: * @@ -1112,6 +1144,15 @@ access_error(unsigned long error_code, struct vm_area_struct *vma) { /* This is only called for the current mm, so: */ bool foreign = false; + + /* + * Read or write was blocked by protection keys. This is + * always an unconditional error and can never result in + * a follow-up action to resolve the fault, like a COW. + */ + if (error_code & PF_PK) + return 1; + /* * Make sure to check the VMA so that we do not perform * faults just to hit a PF_PK as soon as we fill in a |