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159 lines
3.6 KiB
159 lines
3.6 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/sched/debug.h> |
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#include <linux/sched/task_stack.h> |
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#include <linux/stacktrace.h> |
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#include <linux/ftrace.h> |
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#include <linux/ptrace.h> |
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#ifdef CONFIG_FRAME_POINTER |
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struct stackframe { |
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unsigned long fp; |
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unsigned long ra; |
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}; |
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void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, |
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bool (*fn)(unsigned long, void *), void *arg) |
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{ |
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unsigned long fp, sp, pc; |
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if (regs) { |
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fp = frame_pointer(regs); |
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sp = user_stack_pointer(regs); |
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pc = instruction_pointer(regs); |
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} else if (task == NULL || task == current) { |
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const register unsigned long current_sp __asm__ ("sp"); |
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const register unsigned long current_fp __asm__ ("r8"); |
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fp = current_fp; |
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sp = current_sp; |
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pc = (unsigned long)walk_stackframe; |
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} else { |
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/* task blocked in __switch_to */ |
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fp = thread_saved_fp(task); |
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sp = thread_saved_sp(task); |
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pc = thread_saved_lr(task); |
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} |
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for (;;) { |
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unsigned long low, high; |
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struct stackframe *frame; |
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if (unlikely(!__kernel_text_address(pc) || fn(pc, arg))) |
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break; |
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/* Validate frame pointer */ |
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low = sp; |
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high = ALIGN(sp, THREAD_SIZE); |
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if (unlikely(fp < low || fp > high || fp & 0x3)) |
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break; |
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/* Unwind stack frame */ |
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frame = (struct stackframe *)fp; |
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sp = fp; |
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fp = frame->fp; |
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pc = ftrace_graph_ret_addr(current, NULL, frame->ra, |
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(unsigned long *)(fp - 8)); |
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} |
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} |
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#else /* !CONFIG_FRAME_POINTER */ |
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static void notrace walk_stackframe(struct task_struct *task, |
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struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg) |
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{ |
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unsigned long sp, pc; |
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unsigned long *ksp; |
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if (regs) { |
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sp = user_stack_pointer(regs); |
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pc = instruction_pointer(regs); |
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} else if (task == NULL || task == current) { |
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const register unsigned long current_sp __asm__ ("sp"); |
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sp = current_sp; |
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pc = (unsigned long)walk_stackframe; |
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} else { |
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/* task blocked in __switch_to */ |
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sp = thread_saved_sp(task); |
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pc = thread_saved_lr(task); |
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} |
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if (unlikely(sp & 0x3)) |
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return; |
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ksp = (unsigned long *)sp; |
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while (!kstack_end(ksp)) { |
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if (__kernel_text_address(pc) && unlikely(fn(pc, arg))) |
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break; |
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pc = (*ksp++) - 0x4; |
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} |
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} |
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#endif /* CONFIG_FRAME_POINTER */ |
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static bool print_trace_address(unsigned long pc, void *arg) |
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{ |
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print_ip_sym((const char *)arg, pc); |
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return false; |
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} |
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void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl) |
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{ |
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pr_cont("Call Trace:\n"); |
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walk_stackframe(task, NULL, print_trace_address, (void *)loglvl); |
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} |
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static bool save_wchan(unsigned long pc, void *arg) |
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{ |
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if (!in_sched_functions(pc)) { |
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unsigned long *p = arg; |
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*p = pc; |
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return true; |
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} |
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return false; |
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} |
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unsigned long get_wchan(struct task_struct *task) |
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{ |
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unsigned long pc = 0; |
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if (likely(task && task != current && !task_is_running(task))) |
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walk_stackframe(task, NULL, save_wchan, &pc); |
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return pc; |
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} |
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#ifdef CONFIG_STACKTRACE |
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static bool __save_trace(unsigned long pc, void *arg, bool nosched) |
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{ |
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struct stack_trace *trace = arg; |
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if (unlikely(nosched && in_sched_functions(pc))) |
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return false; |
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if (unlikely(trace->skip > 0)) { |
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trace->skip--; |
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return false; |
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} |
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trace->entries[trace->nr_entries++] = pc; |
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return (trace->nr_entries >= trace->max_entries); |
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} |
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static bool save_trace(unsigned long pc, void *arg) |
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{ |
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return __save_trace(pc, arg, false); |
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} |
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/* |
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* Save stack-backtrace addresses into a stack_trace buffer. |
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*/ |
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void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) |
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{ |
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walk_stackframe(tsk, NULL, save_trace, trace); |
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} |
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EXPORT_SYMBOL_GPL(save_stack_trace_tsk); |
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void save_stack_trace(struct stack_trace *trace) |
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{ |
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save_stack_trace_tsk(NULL, trace); |
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} |
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EXPORT_SYMBOL_GPL(save_stack_trace); |
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#endif /* CONFIG_STACKTRACE */
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