diff options
| author | Steve French <sfrench@us.ibm.com> | 2006-06-25 15:57:32 +0000 |
|---|---|---|
| committer | Steve French <sfrench@us.ibm.com> | 2006-06-25 15:57:32 +0000 |
| commit | bbe5d235ee201705530a7153b57e141cd77d818b (patch) | |
| tree | e98c31b4cb2ced6357a87a02596f9ecdbd6dbb26 /arch/i386/mm/fault.c | |
| parent | 189acaaef81b1d71aedd0d28810de24160c2e781 (diff) | |
| parent | dfd8317d3340f03bc06eba6b58f0ec0861da4a13 (diff) | |
Merge with /pub/scm/linux/kernel/git/torvalds/linux-2.6.git
Diffstat (limited to 'arch/i386/mm/fault.c')
| -rw-r--r-- | arch/i386/mm/fault.c | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c index 7f0fcf219a2..bd6fe96cc16 100644 --- a/arch/i386/mm/fault.c +++ b/arch/i386/mm/fault.c @@ -77,12 +77,15 @@ static inline unsigned long get_segment_eip(struct pt_regs *regs, unsigned seg = regs->xcs & 0xffff; u32 seg_ar, seg_limit, base, *desc; + /* Unlikely, but must come before segment checks. */ + if (unlikely(regs->eflags & VM_MASK)) { + base = seg << 4; + *eip_limit = base + 0xffff; + return base + (eip & 0xffff); + } + /* The standard kernel/user address space limit. */ *eip_limit = (seg & 3) ? USER_DS.seg : KERNEL_DS.seg; - - /* Unlikely, but must come before segment checks. */ - if (unlikely((regs->eflags & VM_MASK) != 0)) - return eip + (seg << 4); /* By far the most common cases. */ if (likely(seg == __USER_CS || seg == __KERNEL_CS)) @@ -380,12 +383,12 @@ fastcall void __kprobes do_page_fault(struct pt_regs *regs, goto bad_area; if (error_code & 4) { /* - * accessing the stack below %esp is always a bug. - * The "+ 32" is there due to some instructions (like - * pusha) doing post-decrement on the stack and that - * doesn't show up until later.. + * Accessing the stack below %esp is always a bug. + * The large cushion allows instructions like enter + * and pusha to work. ("enter $65535,$31" pushes + * 32 pointers and then decrements %esp by 65535.) */ - if (address + 32 < regs->esp) + if (address + 65536 + 32 * sizeof(unsigned long) < regs->esp) goto bad_area; } if (expand_stack(vma, address)) |