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c76898373f
Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user). Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred. Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers. Add log level argument to dump_backtrace() as a preparation for introducing show_stack_loglvl(). [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Will Deacon <will@kernel.org> Link: http://lkml.kernel.org/r/20200418201944.482088-10-dima@arista.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
174 lines
4.6 KiB
C
174 lines
4.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2012 ARM Ltd.
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*/
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#ifndef __ASM_STACKTRACE_H
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#define __ASM_STACKTRACE_H
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#include <linux/percpu.h>
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#include <linux/sched.h>
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#include <linux/sched/task_stack.h>
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#include <linux/types.h>
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#include <asm/memory.h>
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#include <asm/ptrace.h>
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#include <asm/sdei.h>
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enum stack_type {
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STACK_TYPE_UNKNOWN,
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STACK_TYPE_TASK,
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STACK_TYPE_IRQ,
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STACK_TYPE_OVERFLOW,
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STACK_TYPE_SDEI_NORMAL,
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STACK_TYPE_SDEI_CRITICAL,
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__NR_STACK_TYPES
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};
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struct stack_info {
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unsigned long low;
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unsigned long high;
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enum stack_type type;
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};
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/*
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* A snapshot of a frame record or fp/lr register values, along with some
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* accounting information necessary for robust unwinding.
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*
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* @fp: The fp value in the frame record (or the real fp)
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* @pc: The fp value in the frame record (or the real lr)
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*
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* @stacks_done: Stacks which have been entirely unwound, for which it is no
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* longer valid to unwind to.
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*
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* @prev_fp: The fp that pointed to this frame record, or a synthetic value
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* of 0. This is used to ensure that within a stack, each
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* subsequent frame record is at an increasing address.
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* @prev_type: The type of stack this frame record was on, or a synthetic
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* value of STACK_TYPE_UNKNOWN. This is used to detect a
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* transition from one stack to another.
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*
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* @graph: When FUNCTION_GRAPH_TRACER is selected, holds the index of a
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* replacement lr value in the ftrace graph stack.
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*/
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struct stackframe {
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unsigned long fp;
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unsigned long pc;
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DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);
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unsigned long prev_fp;
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enum stack_type prev_type;
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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int graph;
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#endif
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};
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extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame);
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extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
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int (*fn)(struct stackframe *, void *), void *data);
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extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
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const char *loglvl);
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DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
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static inline bool on_stack(unsigned long sp, unsigned long low,
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unsigned long high, enum stack_type type,
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struct stack_info *info)
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{
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if (!low)
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return false;
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if (sp < low || sp >= high)
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return false;
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if (info) {
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info->low = low;
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info->high = high;
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info->type = type;
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}
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return true;
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}
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static inline bool on_irq_stack(unsigned long sp,
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struct stack_info *info)
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{
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unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr);
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unsigned long high = low + IRQ_STACK_SIZE;
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return on_stack(sp, low, high, STACK_TYPE_IRQ, info);
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}
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static inline bool on_task_stack(const struct task_struct *tsk,
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unsigned long sp,
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struct stack_info *info)
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{
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unsigned long low = (unsigned long)task_stack_page(tsk);
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unsigned long high = low + THREAD_SIZE;
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return on_stack(sp, low, high, STACK_TYPE_TASK, info);
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}
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#ifdef CONFIG_VMAP_STACK
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DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack);
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static inline bool on_overflow_stack(unsigned long sp,
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struct stack_info *info)
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{
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unsigned long low = (unsigned long)raw_cpu_ptr(overflow_stack);
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unsigned long high = low + OVERFLOW_STACK_SIZE;
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return on_stack(sp, low, high, STACK_TYPE_OVERFLOW, info);
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}
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#else
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static inline bool on_overflow_stack(unsigned long sp,
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struct stack_info *info) { return false; }
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#endif
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/*
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* We can only safely access per-cpu stacks from current in a non-preemptible
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* context.
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*/
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static inline bool on_accessible_stack(const struct task_struct *tsk,
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unsigned long sp,
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struct stack_info *info)
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{
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if (info)
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info->type = STACK_TYPE_UNKNOWN;
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if (on_task_stack(tsk, sp, info))
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return true;
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if (tsk != current || preemptible())
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return false;
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if (on_irq_stack(sp, info))
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return true;
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if (on_overflow_stack(sp, info))
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return true;
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if (on_sdei_stack(sp, info))
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return true;
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return false;
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}
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static inline void start_backtrace(struct stackframe *frame,
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unsigned long fp, unsigned long pc)
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{
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frame->fp = fp;
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frame->pc = pc;
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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frame->graph = 0;
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#endif
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/*
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* Prime the first unwind.
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*
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* In unwind_frame() we'll check that the FP points to a valid stack,
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* which can't be STACK_TYPE_UNKNOWN, and the first unwind will be
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* treated as a transition to whichever stack that happens to be. The
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* prev_fp value won't be used, but we set it to 0 such that it is
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* definitely not an accessible stack address.
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*/
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bitmap_zero(frame->stacks_done, __NR_STACK_TYPES);
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frame->prev_fp = 0;
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frame->prev_type = STACK_TYPE_UNKNOWN;
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}
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#endif /* __ASM_STACKTRACE_H */
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