Commit-ID: a343c75d338aa2afaea4a2a8e40de9e67b6fb4a7
Gitweb: http://git.kernel.org/tip/a343c75d338aa2afaea4a2a8e40de9e67b6fb4a7
Author: H. Peter Anvin <hpa@xxxxxxxxx>
AuthorDate: Mon, 12 Oct 2009 14:11:09 -0700
Committer: H. Peter Anvin <hpa@xxxxxxxxx>
CommitDate: Mon, 12 Oct 2009 14:19:34 -0700
x86: use kernel_stack_pointer() in dumpstack.c
The way to obtain a kernel-mode stack pointer from a struct pt_regs in
32-bit mode is "subtle": the stack doesn't actually contain the stack
pointer, but rather the location where it would have been marks the
actual previous stack frame. For clarity, use kernel_stack_pointer()
instead of coding this weirdness explicitly.
Furthermore, user_mode() is only valid when the process is known to
not run in V86 mode. Use the safer user_mode_vm() instead.
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
---
arch/x86/kernel/dumpstack.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 2d8a371..b8ce165 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -268,11 +268,12 @@ int __kprobes __die(const char *str, struct pt_regs *regs, long err)
show_registers(regs);
#ifdef CONFIG_X86_32
- sp = (unsigned long) (®s->sp);
- savesegment(ss, ss);
- if (user_mode(regs)) {
+ if (user_mode_vm(regs)) {
sp = regs->sp;
ss = regs->ss & 0xffff;
+ } else {
+ sp = kernel_stack_pointer(regs);
+ savesegment(ss, ss);
}
printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
print_symbol("%s", regs->ip);
--
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