x86: fix kernel panic on 32 bits when profiling
Latest kernel has a kernel panic in booting on i386 machine when
profile=2 setting in cmdline. It is due to 'sp' being incorrect in
profile_pc().
BUG: unable to handle kernel NULL pointer dereference at 00000246
IP: [<c01288b6>] profile_pc+0x2a/0x48
*pde = 00000000
Oops: 0000 [#1] SMP
This differs from the original version by Alex Shi in that we use the
kernel_stack_pointer() inline already defined in <asm/ptrace.h> for
this purpose, instead of #ifdef.
Originally-by: Alex Shi <alex.shi@intel.com>
Cc: "Chen, Tim C" <tim.c.chen@intel.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c
index dcb00d2..be25734 100644
--- a/arch/x86/kernel/time.c
+++ b/arch/x86/kernel/time.c
@@ -38,7 +38,8 @@
#ifdef CONFIG_FRAME_POINTER
return *(unsigned long *)(regs->bp + sizeof(long));
#else
- unsigned long *sp = (unsigned long *)regs->sp;
+ unsigned long *sp =
+ (unsigned long *)kernel_stack_pointer(regs);
/*
* Return address is either directly at stack pointer
* or above a saved flags. Eflags has bits 22-31 zero,