> On Thu, 8 Nov 2007 01:45:27 +0000 Robert Fitzsimons <robfitz@273k.net> wrote:
Philippe, on Sun, 21 Oct you sent a "[patch 1/2] oProfile: oops when
profile_pc() return ~0LU" which as far as I can tell never got applied.
Also, I have no record of [patch 2/2] from that day. Can you please refresh
and resend both patches asap?
I've queued the below revert of Jan's change, in case your lost [2/2] doesn't
address Robert's oops.
Robert, can you please test this?
From: Andrew Morton <akpm@linux-foundation.org>
Revert 574a60421c8ea5383a54ebee1f37fa871d00e1b9 - Robert Fitzsimons is
reporting oopses.
Cc: Robert Fitzsimons <robfitz@273k.net>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Philippe Elie <phil.el@wanadoo.fr>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
arch/x86/oprofile/backtrace.c | 97 ++++++++++++++++++++------------
1 file changed, 61 insertions(+), 36 deletions(-)
diff -puN arch/x86/oprofile/backtrace.c~oprofile-revert-i386-make-callgraph-use-dump_trace-on-i386-x86_64 arch/x86/oprofile/backtrace.c
--- a/arch/x86/oprofile/backtrace.c~oprofile-revert-i386-make-callgraph-use-dump_trace-on-i386-x86_64
+++ a/arch/x86/oprofile/backtrace.c
@@ -13,45 +13,25 @@
#include <linux/mm.h>
#include <asm/ptrace.h>
#include <asm/uaccess.h>
-#include <asm/stacktrace.h>
-static void backtrace_warning_symbol(void *data, char *msg,
- unsigned long symbol)
-{
- /* Ignore warnings */
-}
-
-static void backtrace_warning(void *data, char *msg)
-{
- /* Ignore warnings */
-}
+struct frame_head {
+ struct frame_head * ebp;
+ unsigned long ret;
+} __attribute__((packed));
-static int backtrace_stack(void *data, char *name)
+static struct frame_head *
+dump_kernel_backtrace(struct frame_head * head)
{
- /* Yes, we want all stacks */
- return 0;
-}
+ oprofile_add_trace(head->ret);
-static void backtrace_address(void *data, unsigned long addr)
-{
- unsigned int *depth = data;
+ /* frame pointers should strictly progress back up the stack
+ * (towards higher addresses) */
+ if (head >= head->ebp)
+ return NULL;
- if ((*depth)--)
- oprofile_add_trace(addr);
+ return head->ebp;
}
-static struct stacktrace_ops backtrace_ops = {
- .warning = backtrace_warning,
- .warning_symbol = backtrace_warning_symbol,
- .stack = backtrace_stack,
- .address = backtrace_address,
-};
-
-struct frame_head {
- struct frame_head *ebp;
- unsigned long ret;
-} __attribute__((packed));
-
static struct frame_head *
dump_user_backtrace(struct frame_head * head)
{
@@ -73,16 +53,61 @@ dump_user_backtrace(struct frame_head *
return bufhead[0].ebp;
}
+/*
+ * | | /\ Higher addresses
+ * | |
+ * --------------- stack base (address of current_thread_info)
+ * | thread info |
+ * . .
+ * | stack |
+ * --------------- saved regs->ebp value if valid (frame_head address)
+ * . .
+ * --------------- saved regs->rsp value if x86_64
+ * | |
+ * --------------- struct pt_regs * stored on stack if 32-bit
+ * | |
+ * . .
+ * | |
+ * --------------- %esp
+ * | |
+ * | | \/ Lower addresses
+ *
+ * Thus, regs (or regs->rsp for x86_64) <-> stack base restricts the
+ * valid(ish) ebp values. Note: (1) for x86_64, NMI and several other
+ * exceptions use special stacks, maintained by the interrupt stack table
+ * (IST). These stacks are set up in trap_init() in
+ * arch/x86_64/kernel/traps.c. Thus, for x86_64, regs now does not point
+ * to the kernel stack; instead, it points to some location on the NMI
+ * stack. On the other hand, regs->rsp is the stack pointer saved when the
+ * NMI occurred. (2) For 32-bit, regs->esp is not valid because the
+ * processor does not save %esp on the kernel stack when interrupts occur
+ * in the kernel mode.
+ */
+#ifdef CONFIG_FRAME_POINTER
+static int valid_kernel_stack(struct frame_head *head, struct pt_regs *regs)
+{
+ unsigned long headaddr = (unsigned long)head;
+ unsigned long stack = stack_pointer(regs);
+ unsigned long stack_base = (stack & ~(THREAD_SIZE - 1)) + THREAD_SIZE;
+
+ return headaddr > stack && headaddr < stack_base;
+}
+#else
+/* without fp, it's just junk */
+static int valid_kernel_stack(struct frame_head *head, struct pt_regs *regs)
+{
+ return 0;
+}
+#endif
+
void
x86_backtrace(struct pt_regs * const regs, unsigned int depth)
{
struct frame_head *head = (struct frame_head *)frame_pointer(regs);
- unsigned long stack = stack_pointer(regs);
if (!user_mode_vm(regs)) {
- if (depth)
- dump_trace(NULL, regs, (unsigned long *)stack,
- &backtrace_ops, &depth);
+ while (depth-- && valid_kernel_stack(head, regs))
+ head = dump_kernel_backtrace(head);
return;
}
_
-
