diff options
Diffstat (limited to 'arch/x86/mm/fault_64.c')
| -rw-r--r-- | arch/x86/mm/fault_64.c | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c index c6b3ad515cf..c48d95c306d 100644 --- a/arch/x86/mm/fault_64.c +++ b/arch/x86/mm/fault_64.c @@ -440,8 +440,11 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, if (!(vma->vm_flags & VM_GROWSDOWN)) goto bad_area; if (error_code & PF_USER) { - /* Allow userspace just enough access below the stack pointer - * to let the 'enter' instruction work. + /* + * Accessing the stack below %sp is always a bug. + * The large cushion allows instructions like enter + * and pusha to work. ("enter $65535,$31" pushes + * 32 pointers and then decrements %sp by 65535.) */ if (address + 65536 + 32 * sizeof(unsigned long) < regs->sp) goto bad_area; @@ -522,10 +525,14 @@ bad_area_nosemaphore: if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) && printk_ratelimit()) { printk( - "%s%s[%d]: segfault at %lx ip %lx sp %lx error %lx\n", - tsk->pid > 1 ? KERN_INFO : KERN_EMERG, - tsk->comm, tsk->pid, address, regs->ip, - regs->sp, error_code); +#ifdef CONFIG_X86_32 + "%s%s[%d]: segfault at %08lx ip %08lx sp %08lx error %lx\n", +#else + "%s%s[%d]: segfault at %lx ip %lx sp %lx error %lx\n", +#endif + task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, + tsk->comm, task_pid_nr(tsk), address, regs->ip, + regs->sp, error_code); } tsk->thread.cr2 = address; @@ -609,10 +616,12 @@ LIST_HEAD(pgd_list); void vmalloc_sync_all(void) { - /* Note that races in the updates of insync and start aren't - problematic: - insync can only get set bits added, and updates to start are only - improving performance (without affecting correctness if undone). */ + /* + * Note that races in the updates of insync and start aren't + * problematic: insync can only get set bits added, and updates to + * start are only improving performance (without affecting correctness + * if undone). + */ static DECLARE_BITMAP(insync, PTRS_PER_PGD); static unsigned long start = VMALLOC_START & PGDIR_MASK; unsigned long address; |