forked from luck/tmp_suning_uos_patched
b0c51f1584
When doing cat /proc/<PID>/stack, the output is missing the first entry. When the current code walks the stack starting in stack_trace_save_tsk, it skips all scheduler functions (that's OK) plus one more function. But this one function should be skipped only for the 'current' task as it is stack_trace_save_tsk proper. The original code (before the common infrastructure) skipped one function only for the 'current' task -- see save_stack_trace_tsk before3599fe12a1. So do so also in the new infrastructure now. Fixes:214d8ca6ee("stacktrace: Provide common infrastructure") Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Michal Suchanek <msuchanek@suse.de> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20191030072545.19462-1-jslaby@suse.cz
379 lines
9.7 KiB
C
379 lines
9.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* kernel/stacktrace.c
|
|
*
|
|
* Stack trace management functions
|
|
*
|
|
* Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
|
|
*/
|
|
#include <linux/sched/task_stack.h>
|
|
#include <linux/sched/debug.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/export.h>
|
|
#include <linux/kallsyms.h>
|
|
#include <linux/stacktrace.h>
|
|
|
|
/**
|
|
* stack_trace_print - Print the entries in the stack trace
|
|
* @entries: Pointer to storage array
|
|
* @nr_entries: Number of entries in the storage array
|
|
* @spaces: Number of leading spaces to print
|
|
*/
|
|
void stack_trace_print(const unsigned long *entries, unsigned int nr_entries,
|
|
int spaces)
|
|
{
|
|
unsigned int i;
|
|
|
|
if (WARN_ON(!entries))
|
|
return;
|
|
|
|
for (i = 0; i < nr_entries; i++)
|
|
printk("%*c%pS\n", 1 + spaces, ' ', (void *)entries[i]);
|
|
}
|
|
EXPORT_SYMBOL_GPL(stack_trace_print);
|
|
|
|
/**
|
|
* stack_trace_snprint - Print the entries in the stack trace into a buffer
|
|
* @buf: Pointer to the print buffer
|
|
* @size: Size of the print buffer
|
|
* @entries: Pointer to storage array
|
|
* @nr_entries: Number of entries in the storage array
|
|
* @spaces: Number of leading spaces to print
|
|
*
|
|
* Return: Number of bytes printed.
|
|
*/
|
|
int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries,
|
|
unsigned int nr_entries, int spaces)
|
|
{
|
|
unsigned int generated, i, total = 0;
|
|
|
|
if (WARN_ON(!entries))
|
|
return 0;
|
|
|
|
for (i = 0; i < nr_entries && size; i++) {
|
|
generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ',
|
|
(void *)entries[i]);
|
|
|
|
total += generated;
|
|
if (generated >= size) {
|
|
buf += size;
|
|
size = 0;
|
|
} else {
|
|
buf += generated;
|
|
size -= generated;
|
|
}
|
|
}
|
|
|
|
return total;
|
|
}
|
|
EXPORT_SYMBOL_GPL(stack_trace_snprint);
|
|
|
|
#ifdef CONFIG_ARCH_STACKWALK
|
|
|
|
struct stacktrace_cookie {
|
|
unsigned long *store;
|
|
unsigned int size;
|
|
unsigned int skip;
|
|
unsigned int len;
|
|
};
|
|
|
|
static bool stack_trace_consume_entry(void *cookie, unsigned long addr,
|
|
bool reliable)
|
|
{
|
|
struct stacktrace_cookie *c = cookie;
|
|
|
|
if (c->len >= c->size)
|
|
return false;
|
|
|
|
if (c->skip > 0) {
|
|
c->skip--;
|
|
return true;
|
|
}
|
|
c->store[c->len++] = addr;
|
|
return c->len < c->size;
|
|
}
|
|
|
|
static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr,
|
|
bool reliable)
|
|
{
|
|
if (in_sched_functions(addr))
|
|
return true;
|
|
return stack_trace_consume_entry(cookie, addr, reliable);
|
|
}
|
|
|
|
/**
|
|
* stack_trace_save - Save a stack trace into a storage array
|
|
* @store: Pointer to storage array
|
|
* @size: Size of the storage array
|
|
* @skipnr: Number of entries to skip at the start of the stack trace
|
|
*
|
|
* Return: Number of trace entries stored.
|
|
*/
|
|
unsigned int stack_trace_save(unsigned long *store, unsigned int size,
|
|
unsigned int skipnr)
|
|
{
|
|
stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
|
|
struct stacktrace_cookie c = {
|
|
.store = store,
|
|
.size = size,
|
|
.skip = skipnr + 1,
|
|
};
|
|
|
|
arch_stack_walk(consume_entry, &c, current, NULL);
|
|
return c.len;
|
|
}
|
|
EXPORT_SYMBOL_GPL(stack_trace_save);
|
|
|
|
/**
|
|
* stack_trace_save_tsk - Save a task stack trace into a storage array
|
|
* @task: The task to examine
|
|
* @store: Pointer to storage array
|
|
* @size: Size of the storage array
|
|
* @skipnr: Number of entries to skip at the start of the stack trace
|
|
*
|
|
* Return: Number of trace entries stored.
|
|
*/
|
|
unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
|
|
unsigned int size, unsigned int skipnr)
|
|
{
|
|
stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched;
|
|
struct stacktrace_cookie c = {
|
|
.store = store,
|
|
.size = size,
|
|
/* skip this function if they are tracing us */
|
|
.skip = skipnr + !!(current == tsk),
|
|
};
|
|
|
|
if (!try_get_task_stack(tsk))
|
|
return 0;
|
|
|
|
arch_stack_walk(consume_entry, &c, tsk, NULL);
|
|
put_task_stack(tsk);
|
|
return c.len;
|
|
}
|
|
|
|
/**
|
|
* stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
|
|
* @regs: Pointer to pt_regs to examine
|
|
* @store: Pointer to storage array
|
|
* @size: Size of the storage array
|
|
* @skipnr: Number of entries to skip at the start of the stack trace
|
|
*
|
|
* Return: Number of trace entries stored.
|
|
*/
|
|
unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
|
|
unsigned int size, unsigned int skipnr)
|
|
{
|
|
stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
|
|
struct stacktrace_cookie c = {
|
|
.store = store,
|
|
.size = size,
|
|
.skip = skipnr,
|
|
};
|
|
|
|
arch_stack_walk(consume_entry, &c, current, regs);
|
|
return c.len;
|
|
}
|
|
|
|
#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
|
|
/**
|
|
* stack_trace_save_tsk_reliable - Save task stack with verification
|
|
* @tsk: Pointer to the task to examine
|
|
* @store: Pointer to storage array
|
|
* @size: Size of the storage array
|
|
*
|
|
* Return: An error if it detects any unreliable features of the
|
|
* stack. Otherwise it guarantees that the stack trace is
|
|
* reliable and returns the number of entries stored.
|
|
*
|
|
* If the task is not 'current', the caller *must* ensure the task is inactive.
|
|
*/
|
|
int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
|
|
unsigned int size)
|
|
{
|
|
stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
|
|
struct stacktrace_cookie c = {
|
|
.store = store,
|
|
.size = size,
|
|
};
|
|
int ret;
|
|
|
|
/*
|
|
* If the task doesn't have a stack (e.g., a zombie), the stack is
|
|
* "reliably" empty.
|
|
*/
|
|
if (!try_get_task_stack(tsk))
|
|
return 0;
|
|
|
|
ret = arch_stack_walk_reliable(consume_entry, &c, tsk);
|
|
put_task_stack(tsk);
|
|
return ret ? ret : c.len;
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_USER_STACKTRACE_SUPPORT
|
|
/**
|
|
* stack_trace_save_user - Save a user space stack trace into a storage array
|
|
* @store: Pointer to storage array
|
|
* @size: Size of the storage array
|
|
*
|
|
* Return: Number of trace entries stored.
|
|
*/
|
|
unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
|
|
{
|
|
stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
|
|
struct stacktrace_cookie c = {
|
|
.store = store,
|
|
.size = size,
|
|
};
|
|
mm_segment_t fs;
|
|
|
|
/* Trace user stack if not a kernel thread */
|
|
if (current->flags & PF_KTHREAD)
|
|
return 0;
|
|
|
|
fs = get_fs();
|
|
set_fs(USER_DS);
|
|
arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
|
|
set_fs(fs);
|
|
|
|
return c.len;
|
|
}
|
|
#endif
|
|
|
|
#else /* CONFIG_ARCH_STACKWALK */
|
|
|
|
/*
|
|
* Architectures that do not implement save_stack_trace_*()
|
|
* get these weak aliases and once-per-bootup warnings
|
|
* (whenever this facility is utilized - for example by procfs):
|
|
*/
|
|
__weak void
|
|
save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
|
|
{
|
|
WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
|
|
}
|
|
|
|
__weak void
|
|
save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
|
|
{
|
|
WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
|
|
}
|
|
|
|
/**
|
|
* stack_trace_save - Save a stack trace into a storage array
|
|
* @store: Pointer to storage array
|
|
* @size: Size of the storage array
|
|
* @skipnr: Number of entries to skip at the start of the stack trace
|
|
*
|
|
* Return: Number of trace entries stored
|
|
*/
|
|
unsigned int stack_trace_save(unsigned long *store, unsigned int size,
|
|
unsigned int skipnr)
|
|
{
|
|
struct stack_trace trace = {
|
|
.entries = store,
|
|
.max_entries = size,
|
|
.skip = skipnr + 1,
|
|
};
|
|
|
|
save_stack_trace(&trace);
|
|
return trace.nr_entries;
|
|
}
|
|
EXPORT_SYMBOL_GPL(stack_trace_save);
|
|
|
|
/**
|
|
* stack_trace_save_tsk - Save a task stack trace into a storage array
|
|
* @task: The task to examine
|
|
* @store: Pointer to storage array
|
|
* @size: Size of the storage array
|
|
* @skipnr: Number of entries to skip at the start of the stack trace
|
|
*
|
|
* Return: Number of trace entries stored
|
|
*/
|
|
unsigned int stack_trace_save_tsk(struct task_struct *task,
|
|
unsigned long *store, unsigned int size,
|
|
unsigned int skipnr)
|
|
{
|
|
struct stack_trace trace = {
|
|
.entries = store,
|
|
.max_entries = size,
|
|
/* skip this function if they are tracing us */
|
|
.skip = skipnr + !!(current == task),
|
|
};
|
|
|
|
save_stack_trace_tsk(task, &trace);
|
|
return trace.nr_entries;
|
|
}
|
|
|
|
/**
|
|
* stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
|
|
* @regs: Pointer to pt_regs to examine
|
|
* @store: Pointer to storage array
|
|
* @size: Size of the storage array
|
|
* @skipnr: Number of entries to skip at the start of the stack trace
|
|
*
|
|
* Return: Number of trace entries stored
|
|
*/
|
|
unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
|
|
unsigned int size, unsigned int skipnr)
|
|
{
|
|
struct stack_trace trace = {
|
|
.entries = store,
|
|
.max_entries = size,
|
|
.skip = skipnr,
|
|
};
|
|
|
|
save_stack_trace_regs(regs, &trace);
|
|
return trace.nr_entries;
|
|
}
|
|
|
|
#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
|
|
/**
|
|
* stack_trace_save_tsk_reliable - Save task stack with verification
|
|
* @tsk: Pointer to the task to examine
|
|
* @store: Pointer to storage array
|
|
* @size: Size of the storage array
|
|
*
|
|
* Return: An error if it detects any unreliable features of the
|
|
* stack. Otherwise it guarantees that the stack trace is
|
|
* reliable and returns the number of entries stored.
|
|
*
|
|
* If the task is not 'current', the caller *must* ensure the task is inactive.
|
|
*/
|
|
int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
|
|
unsigned int size)
|
|
{
|
|
struct stack_trace trace = {
|
|
.entries = store,
|
|
.max_entries = size,
|
|
};
|
|
int ret = save_stack_trace_tsk_reliable(tsk, &trace);
|
|
|
|
return ret ? ret : trace.nr_entries;
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_USER_STACKTRACE_SUPPORT
|
|
/**
|
|
* stack_trace_save_user - Save a user space stack trace into a storage array
|
|
* @store: Pointer to storage array
|
|
* @size: Size of the storage array
|
|
*
|
|
* Return: Number of trace entries stored
|
|
*/
|
|
unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
|
|
{
|
|
struct stack_trace trace = {
|
|
.entries = store,
|
|
.max_entries = size,
|
|
};
|
|
|
|
save_stack_trace_user(&trace);
|
|
return trace.nr_entries;
|
|
}
|
|
#endif /* CONFIG_USER_STACKTRACE_SUPPORT */
|
|
|
|
#endif /* !CONFIG_ARCH_STACKWALK */
|