1 // SPDX-License-Identifier: GPL-2.0
40 	int size;  in print_max_stack()  local
42 	pr_emerg("        Depth    Size   Location    (%d entries)\n"  in print_max_stack()
43 			   "        -----    ----   --------\n",  in print_max_stack()
48 			size = stack_trace_index[i];  in print_max_stack()
50 			size = stack_trace_index[i] - stack_trace_index[i+1];  in print_max_stack()
53 				size, (void *)stack_dump_trace[i]);  in print_max_stack()
60  * size. It determines the stack size from the variable passed in, which is the
62  * The stack size is calculated by the address of the local variable to the top
63  * of the current stack. If that size is smaller than the currently saved max
64  * stack size, nothing more is done.
66  * If the size of the stack is greater than the maximum recorded size, then the
74  *    0: sys call entry frame
76  *   11: start of sys_foo frame
78  *   21: start of kernel_func_bar frame
89  * Now to figure out how much each of these functions' local variable size is,
95  *        ------------------        +   -------------------
100  * The print_max_stack() function above, uses these values to print the size of
104  *     size = i == nr_entries - 1 ? stack_trace_index[i] :
105  *                    stack_trace_index[i] - stack_trace_index[i+1]
106  *     print "%d %d %d %s\n", i, stack_trace_index[i], size, stack_dump_trace[i]);
111  *     depth size  location
112  *     ----- ----  --------
122  *  0: sys call entry frame
125  * 20: start of kernel_func_bar frame
134  *        ------------------        +   -------------------
141  *   kernel_func_bar stack frame size is 29 - 19 not 30 - 29!
148  *        ------------------        +   -------------------
153  * will still include the stack size of it.
162 	this_size = ((unsigned long)stack) & (THREAD_SIZE-1);  in check_stack()
163 	this_size = THREAD_SIZE - this_size;  in check_stack()
164 	/* Remove the frame of the tracer */  in check_stack()
165 	this_size -= frame_size;  in check_stack()
183 		this_size -= tracer_frame;  in check_stack()
192 					       ARRAY_SIZE(stack_dump_trace) - 1,  in check_stack()
214 		(((unsigned long)start & ~(THREAD_SIZE-1)) + THREAD_SIZE);  in check_stack()
221 	 * on a new max, so it is far from a fast path.  in check_stack()
232 			 * this is not a stack-out-of-bounds error.  in check_stack()
237 					(top - p) * sizeof(unsigned long);  in check_stack()
244 				 * max stack. If we haven't figured  in check_stack()
249 					tracer_frame = (p - stack) *  in check_stack()
251 					stack_trace_max_size -= tracer_frame;  in check_stack()
269 			sizeof(stack_trace_index[0]) * (x - 1));  in check_stack()
270 		x--;  in check_stack()
327 	unsigned long *ptr = filp->private_data;  in stack_max_size_read()
341 	long *ptr = filp->private_data;  in stack_max_size_write()
378 	long n = *pos - 1;  in __next()
383 	m->private = (void *)n;  in __next()
384 	return &m->private;  in __next()
438 	int size;  in t_show()  local
441 		seq_printf(m, "        Depth    Size   Location"  in t_show()
443 			   "        -----    ----   --------\n",  in t_show()
458 		size = stack_trace_index[i];  in t_show()
460 		size = stack_trace_index[i] - stack_trace_index[i+1];  in t_show()
462 	seq_printf(m, "%3ld) %8d   %5d   ", i, stack_trace_index[i], size);  in t_show()
499 	struct ftrace_ops *ops = inode->i_private;  in stack_trace_filter_open()