I think there's an anomaly in stack_depot_s*print(). If we have zero
entries, we don't copy anything, which means the string is still not a
string. Normally, this function is called surrounded by other calls to
s*printf(), which guarantee that there's a '\0', but maybe we should
make sure to write a '\0' here?
Cc: Kees Cook <k...@kernel.org>
Cc: Christopher Bazley <chris.bazley.w...@gmail.com>
Signed-off-by: Alejandro Colomar <a...@kernel.org>
---
include/linux/stackdepot.h | 13 +++++++++++++
include/linux/stacktrace.h | 3 +++
kernel/stacktrace.c | 28 ++++++++++++++++++++++++++++
lib/stackdepot.c | 12 ++++++++++++
4 files changed, 56 insertions(+)
diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h
index 2cc21ffcdaf9..a7749fc3ac7c 100644
--- a/include/linux/stackdepot.h
+++ b/include/linux/stackdepot.h
@@ -219,6 +219,19 @@ void stack_depot_print(depot_stack_handle_t stack);
int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size,
int spaces);
+/**
+ * stack_depot_seprint - Print a stack trace from stack depot into a buffer
+ *
+ * @handle: Stack depot handle returned from stack_depot_save()
+ * @p: Pointer to the print buffer
+ * @end: Pointer to one past the last element in the buffer
+ * @spaces: Number of leading spaces to print
+ *
+ * Return: Pointer to trailing '\0'; or NULL on truncation
+ */
+char *stack_depot_seprint(depot_stack_handle_t handle, char *p,
+ const char end[0], int spaces);
+
/**
* stack_depot_put - Drop a reference to a stack trace from stack depot
*
diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h
index 97455880ac41..748936386c89 100644
--- a/include/linux/stacktrace.h
+++ b/include/linux/stacktrace.h
@@ -67,6 +67,9 @@ void stack_trace_print(const unsigned long *trace, unsigned
int nr_entries,
int spaces);
int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries,
unsigned int nr_entries, int spaces);
+char *stack_trace_seprint(char *p, const char end[0],
+ const unsigned long *entries, unsigned int nr_entries,
+ int spaces);
unsigned int stack_trace_save(unsigned long *store, unsigned int size,
unsigned int skipnr);
unsigned int stack_trace_save_tsk(struct task_struct *task,
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index afb3c116da91..65caf9e63673 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -70,6 +70,34 @@ int stack_trace_snprint(char *buf, size_t size, const
unsigned long *entries,
}
EXPORT_SYMBOL_GPL(stack_trace_snprint);
+/**
+ * stack_trace_seprint - Print the entries in the stack trace into a buffer
+ * @p: Pointer to the print buffer
+ * @end: Pointer to one past the last element in the buffer
+ * @entries: Pointer to storage array
+ * @nr_entries: Number of entries in the storage array
+ * @spaces: Number of leading spaces to print
+ *
+ * Return: Pointer to the trailing '\0'; or NULL on truncation.
+ */
+char *stack_trace_seprint(char *p, const char end[0],
+ const unsigned long *entries, unsigned int nr_entries,
+ int spaces)
+{
+ unsigned int i;
+
+ if (WARN_ON(!entries))
+ return 0;
+
+ for (i = 0; i < nr_entries; i++) {
+ p = seprintf(p, end, "%*c%pS\n", 1 + spaces, ' ',
+ (void *)entries[i]);
+ }
+
+ return p;
+}
+EXPORT_SYMBOL_GPL(stack_trace_seprint);
+
#ifdef CONFIG_ARCH_STACKWALK
struct stacktrace_cookie {
diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index 73d7b50924ef..749496e6a6f1 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -771,6 +771,18 @@ int stack_depot_snprint(depot_stack_handle_t handle, char
*buf, size_t size,
}
EXPORT_SYMBOL_GPL(stack_depot_snprint);
+char *stack_depot_seprint(depot_stack_handle_t handle, char *p,
+ const char end[0], int spaces)
+{
+ unsigned long *entries;
+ unsigned int nr_entries;
+
+ nr_entries = stack_depot_fetch(handle, &entries);
+ return nr_entries ? stack_trace_seprint(p, end, entries, nr_entries,
+ spaces) : p;
+}
+EXPORT_SYMBOL_GPL(stack_depot_seprint);
+
depot_stack_handle_t __must_check stack_depot_set_extra_bits(
depot_stack_handle_t handle, unsigned int extra_bits)
{
--
2.50.0
