5f639fdcd8
Fix a long-standing bug in the stack backtracer where we would print garbage to the console instead of kernel function names, if the kernel wasn't built with symbol support (e.g. mboot). Make sure to tag every line of userspace backtrace output if we actually have the mmap_sem, since that way if there's no tag, we know that it's because we couldn't trylock the semaphore. Stop doing a TLB flush and examining page tables during backtrace. Instead, just trust that __copy_from_user_inatomic() will properly fault and return a failure, which it should do in all cases. Fix a latent bug where the backtracer would directly examine a signal context in user space, rather than copying it safely to kernel memory first. This meant that a race with another thread could potentially have caused a kernel panic. Guard against unaligned sp when trying to restart backtrace at an interrupt or signal handler point in the kernel backtracer. Report kernel symbolic information for the call instruction rather than for the following instruction. We still report the actual numeric address corresponding to the instruction after the call, for the sake of consistency with the normal expectations for stack backtracers. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
74 lines
2.7 KiB
C
74 lines
2.7 KiB
C
/*
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* Copyright 2010 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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#ifndef _ASM_TILE_STACK_H
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#define _ASM_TILE_STACK_H
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <asm/backtrace.h>
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#include <asm/page.h>
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#include <hv/hypervisor.h>
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/* Everything we need to keep track of a backtrace iteration */
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struct KBacktraceIterator {
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BacktraceIterator it;
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struct task_struct *task; /* task we are backtracing */
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int end; /* iteration complete. */
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int new_context; /* new context is starting */
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int profile; /* profiling, so stop on async intrpt */
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int verbose; /* printk extra info (don't want to
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* do this for profiling) */
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int is_current; /* backtracing current task */
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};
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/* Iteration methods for kernel backtraces */
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/*
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* Initialize a KBacktraceIterator from a task_struct, and optionally from
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* a set of registers. If the registers are omitted, the process is
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* assumed to be descheduled, and registers are read from the process's
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* thread_struct and stack. "verbose" means to printk some additional
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* information about fault handlers as we pass them on the stack.
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*/
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extern void KBacktraceIterator_init(struct KBacktraceIterator *kbt,
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struct task_struct *, struct pt_regs *);
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/* Initialize iterator based on current stack. */
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extern void KBacktraceIterator_init_current(struct KBacktraceIterator *kbt);
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/* Helper method for above. */
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extern void _KBacktraceIterator_init_current(struct KBacktraceIterator *kbt,
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ulong pc, ulong lr, ulong sp, ulong r52);
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/* No more frames? */
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extern int KBacktraceIterator_end(struct KBacktraceIterator *kbt);
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/* Advance to the next frame. */
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extern void KBacktraceIterator_next(struct KBacktraceIterator *kbt);
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/*
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* Dump stack given complete register info. Use only from the
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* architecture-specific code; show_stack()
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* and dump_stack() (in entry.S) are architecture-independent entry points.
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*/
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extern void tile_show_stack(struct KBacktraceIterator *, int headers);
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/* Dump stack of current process, with registers to seed the backtrace. */
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extern void dump_stack_regs(struct pt_regs *);
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/* Helper method for assembly dump_stack(). */
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extern void _dump_stack(int dummy, ulong pc, ulong lr, ulong sp, ulong r52);
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#endif /* _ASM_TILE_STACK_H */
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