History

stacktrace: Provide common infrastructure

All architectures which support stacktrace carry duplicated code and do the stack storage and filtering at the architecture side. Provide a consolidated interface with a callback function for consuming the stack entries provided by the architecture specific stack walker. This removes lots of duplicated code and allows to implement better filtering than 'skip number of entries' in the future without touching any architecture specific code.

Thomas Gleixner committed 7 years ago

Commit 214d8ca1 parent 56d8f073 files · +216 −0Browse files

Showing the changes to kernel/stacktrace.c (1 of 3 files). Show all

Unified · Split

kernel/stacktrace.c+173−0
@@ -5,6 +5,8 @@ · 4 unmodified lines
55 *
66 * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
77 */
8+#include <linux/sched/task_stack.h>
9+#include <linux/sched/debug.h>
810 #include <linux/sched.h>
911 #include <linux/kernel.h>
1012 #include <linux/export.h>
@@ -66,6 +68,175 @@ int stack_trace_snprint(char *buf, size_t size, unsigned long *entries, · 55 unmodified lines
6668 }
6769 EXPORT_SYMBOL_GPL(stack_trace_snprint);
6870
71+#ifdef CONFIG_ARCH_STACKWALK
72+
73+struct stacktrace_cookie {
74+ unsigned long *store;
75+ unsigned int size;
76+ unsigned int skip;
77+ unsigned int len;
78+};
79+
80+static bool stack_trace_consume_entry(void *cookie, unsigned long addr,
81+ bool reliable)
82+{
83+ struct stacktrace_cookie *c = cookie;
84+
85+ if (c->len >= c->size)
86+ return false;
87+
88+ if (c->skip > 0) {
89+ c->skip--;
90+ return true;
91+ }
92+ c->store[c->len++] = addr;
93+ return c->len < c->size;
94+}
95+
96+static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr,
97+ bool reliable)
98+{
99+ if (in_sched_functions(addr))
100+ return true;
101+ return stack_trace_consume_entry(cookie, addr, reliable);
102+}
103+
104+/**
105+ * stack_trace_save - Save a stack trace into a storage array
106+ * @store: Pointer to storage array
107+ * @size: Size of the storage array
108+ * @skipnr: Number of entries to skip at the start of the stack trace
109+ *
110+ * Return: Number of trace entries stored.
111+ */
112+unsigned int stack_trace_save(unsigned long *store, unsigned int size,
113+ unsigned int skipnr)
114+{
115+ stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
116+ struct stacktrace_cookie c = {
117+ .store = store,
118+ .size = size,
119+ .skip = skipnr + 1,
120+ };
121+
122+ arch_stack_walk(consume_entry, &c, current, NULL);
123+ return c.len;
124+}
125+EXPORT_SYMBOL_GPL(stack_trace_save);
126+
127+/**
128+ * stack_trace_save_tsk - Save a task stack trace into a storage array
129+ * @task: The task to examine
130+ * @store: Pointer to storage array
131+ * @size: Size of the storage array
132+ * @skipnr: Number of entries to skip at the start of the stack trace
133+ *
134+ * Return: Number of trace entries stored.
135+ */
136+unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
137+ unsigned int size, unsigned int skipnr)
138+{
139+ stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched;
140+ struct stacktrace_cookie c = {
141+ .store = store,
142+ .size = size,
143+ .skip = skipnr + 1,
144+ };
145+
146+ if (!try_get_task_stack(tsk))
147+ return 0;
148+
149+ arch_stack_walk(consume_entry, &c, tsk, NULL);
150+ put_task_stack(tsk);
151+ return c.len;
152+}
153+
154+/**
155+ * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
156+ * @regs: Pointer to pt_regs to examine
157+ * @store: Pointer to storage array
158+ * @size: Size of the storage array
159+ * @skipnr: Number of entries to skip at the start of the stack trace
160+ *
161+ * Return: Number of trace entries stored.
162+ */
163+unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
164+ unsigned int size, unsigned int skipnr)
165+{
166+ stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
167+ struct stacktrace_cookie c = {
168+ .store = store,
169+ .size = size,
170+ .skip = skipnr,
171+ };
172+
173+ arch_stack_walk(consume_entry, &c, current, regs);
174+ return c.len;
175+}
176+
177+#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
178+/**
179+ * stack_trace_save_tsk_reliable - Save task stack with verification
180+ * @tsk: Pointer to the task to examine
181+ * @store: Pointer to storage array
182+ * @size: Size of the storage array
183+ *
184+ * Return: An error if it detects any unreliable features of the
185+ * stack. Otherwise it guarantees that the stack trace is
186+ * reliable and returns the number of entries stored.
187+ *
188+ * If the task is not 'current', the caller *must* ensure the task is inactive.
189+ */
190+int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
191+ unsigned int size)
192+{
193+ stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
194+ struct stacktrace_cookie c = {
195+ .store = store,
196+ .size = size,
197+ };
198+ int ret;
199+
200+ /*
201+ * If the task doesn't have a stack (e.g., a zombie), the stack is
202+ * "reliably" empty.
203+ */
204+ if (!try_get_task_stack(tsk))
205+ return 0;
206+
207+ ret = arch_stack_walk_reliable(consume_entry, &c, tsk);
208+ put_task_stack(tsk);
209+ return ret;
210+}
211+#endif
212+
213+#ifdef CONFIG_USER_STACKTRACE_SUPPORT
214+/**
215+ * stack_trace_save_user - Save a user space stack trace into a storage array
216+ * @store: Pointer to storage array
217+ * @size: Size of the storage array
218+ *
219+ * Return: Number of trace entries stored.
220+ */
221+unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
222+{
223+ stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
224+ struct stacktrace_cookie c = {
225+ .store = store,
226+ .size = size,
227+ };
228+
229+ /* Trace user stack if not a kernel thread */
230+ if (!current->mm)
231+ return 0;
232+
233+ arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
234+ return c.len;
235+}
236+#endif
237+
238+#else /* CONFIG_ARCH_STACKWALK */
239+
69240 /*
70241 * Architectures that do not implement save_stack_trace_*()
71242 * get these weak aliases and once-per-bootup warnings
@@ -203,3 +374,5 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) · 131 unmodified lines
203374 return trace.nr_entries;
204375 }
205376 #endif /* CONFIG_USER_STACKTRACE_SUPPORT */
377+
378+#endif /* !CONFIG_ARCH_STACKWALK */