e8e999cf3c
Current stack dump code scans entire stack and check each entry
contains a pointer to kernel code. If CONFIG_FRAME_POINTER=y it
could mark whether the pointer is valid or not based on value of
the frame pointer. Invalid entries could be preceded by '?' sign.
However this was not going to happen because scan start point
was always higher than the frame pointer so that they could not
meet.
Commit 9c0729dc80 ("x86: Eliminate bp argument from the stack
tracing routines") delayed bp acquisition point, so the bp was
read in lower frame, thus all of the entries were marked
invalid.
This patch fixes this by reverting above commit while retaining
stack_frame() helper as suggested by Frederic Weisbecker.
End result looks like below:
before:
[ 3.508329] Call Trace:
[ 3.508551] [<ffffffff814f35c9>] ? panic+0x91/0x199
[ 3.508662] [<ffffffff814f3739>] ? printk+0x68/0x6a
[ 3.508770] [<ffffffff81a981b2>] ? mount_block_root+0x257/0x26e
[ 3.508876] [<ffffffff81a9821f>] ? mount_root+0x56/0x5a
[ 3.508975] [<ffffffff81a98393>] ? prepare_namespace+0x170/0x1a9
[ 3.509216] [<ffffffff81a9772b>] ? kernel_init+0x1d2/0x1e2
[ 3.509335] [<ffffffff81003894>] ? kernel_thread_helper+0x4/0x10
[ 3.509442] [<ffffffff814f6880>] ? restore_args+0x0/0x30
[ 3.509542] [<ffffffff81a97559>] ? kernel_init+0x0/0x1e2
[ 3.509641] [<ffffffff81003890>] ? kernel_thread_helper+0x0/0x10
after:
[ 3.522991] Call Trace:
[ 3.523351] [<ffffffff814f35b9>] panic+0x91/0x199
[ 3.523468] [<ffffffff814f3729>] ? printk+0x68/0x6a
[ 3.523576] [<ffffffff81a981b2>] mount_block_root+0x257/0x26e
[ 3.523681] [<ffffffff81a9821f>] mount_root+0x56/0x5a
[ 3.523780] [<ffffffff81a98393>] prepare_namespace+0x170/0x1a9
[ 3.523885] [<ffffffff81a9772b>] kernel_init+0x1d2/0x1e2
[ 3.523987] [<ffffffff81003894>] kernel_thread_helper+0x4/0x10
[ 3.524228] [<ffffffff814f6880>] ? restore_args+0x0/0x30
[ 3.524345] [<ffffffff81a97559>] ? kernel_init+0x0/0x1e2
[ 3.524445] [<ffffffff81003890>] ? kernel_thread_helper+0x0/0x10
-v5:
* fix build breakage with oprofile
-v4:
* use 0 instead of regs->bp
* separate out printk changes
-v3:
* apply comment from Frederic
* add a couple of printk fixes
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Soren Sandmann <ssp@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1300416006-3163-1-git-send-email-namhyung@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
122 lines
2.9 KiB
C
122 lines
2.9 KiB
C
/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
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*/
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#ifndef _ASM_X86_STACKTRACE_H
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#define _ASM_X86_STACKTRACE_H
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#include <linux/uaccess.h>
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#include <linux/ptrace.h>
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extern int kstack_depth_to_print;
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struct thread_info;
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struct stacktrace_ops;
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typedef unsigned long (*walk_stack_t)(struct thread_info *tinfo,
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unsigned long *stack,
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unsigned long bp,
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const struct stacktrace_ops *ops,
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void *data,
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unsigned long *end,
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int *graph);
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extern unsigned long
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print_context_stack(struct thread_info *tinfo,
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unsigned long *stack, unsigned long bp,
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const struct stacktrace_ops *ops, void *data,
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unsigned long *end, int *graph);
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extern unsigned long
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print_context_stack_bp(struct thread_info *tinfo,
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unsigned long *stack, unsigned long bp,
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const struct stacktrace_ops *ops, void *data,
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unsigned long *end, int *graph);
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/* Generic stack tracer with callbacks */
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struct stacktrace_ops {
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void (*warning)(void *data, char *msg);
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/* msg must contain %s for the symbol */
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void (*warning_symbol)(void *data, char *msg, unsigned long symbol);
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void (*address)(void *data, unsigned long address, int reliable);
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/* On negative return stop dumping */
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int (*stack)(void *data, char *name);
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walk_stack_t walk_stack;
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};
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void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
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unsigned long *stack, unsigned long bp,
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const struct stacktrace_ops *ops, void *data);
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#ifdef CONFIG_X86_32
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#define STACKSLOTS_PER_LINE 8
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#define get_bp(bp) asm("movl %%ebp, %0" : "=r" (bp) :)
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#else
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#define STACKSLOTS_PER_LINE 4
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#define get_bp(bp) asm("movq %%rbp, %0" : "=r" (bp) :)
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#endif
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#ifdef CONFIG_FRAME_POINTER
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static inline unsigned long
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stack_frame(struct task_struct *task, struct pt_regs *regs)
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{
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unsigned long bp;
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if (regs)
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return regs->bp;
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if (task == current) {
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/* Grab bp right from our regs */
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get_bp(bp);
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return bp;
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}
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/* bp is the last reg pushed by switch_to */
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return *(unsigned long *)task->thread.sp;
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}
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#else
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static inline unsigned long
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stack_frame(struct task_struct *task, struct pt_regs *regs)
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{
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return 0;
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}
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#endif
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extern void
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show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
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unsigned long *stack, unsigned long bp, char *log_lvl);
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extern void
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show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
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unsigned long *sp, unsigned long bp, char *log_lvl);
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extern unsigned int code_bytes;
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/* The form of the top of the frame on the stack */
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struct stack_frame {
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struct stack_frame *next_frame;
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unsigned long return_address;
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};
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struct stack_frame_ia32 {
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u32 next_frame;
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u32 return_address;
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};
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static inline unsigned long caller_frame_pointer(void)
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{
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struct stack_frame *frame;
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get_bp(frame);
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#ifdef CONFIG_FRAME_POINTER
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frame = frame->next_frame;
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#endif
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return (unsigned long)frame;
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}
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#endif /* _ASM_X86_STACKTRACE_H */
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