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-rw-r--r--arch/s390/Kconfig1
-rw-r--r--arch/s390/kernel/stacktrace.c43
2 files changed, 44 insertions, 0 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 2528eb9d01fb..367a87c5d7b8 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -170,6 +170,7 @@ config S390
select HAVE_PERF_EVENTS
select HAVE_RCU_TABLE_FREE
select HAVE_REGS_AND_STACK_ACCESS_API
+ select HAVE_RELIABLE_STACKTRACE
select HAVE_RSEQ
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_VIRT_CPU_ACCOUNTING
diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index f8fc4f8aef9b..fc5419ac64c8 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -9,6 +9,7 @@
#include <linux/stacktrace.h>
#include <asm/stacktrace.h>
#include <asm/unwind.h>
+#include <asm/kprobes.h>
void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
struct task_struct *task, struct pt_regs *regs)
@@ -22,3 +23,45 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
break;
}
}
+
+/*
+ * This function returns an error if it detects any unreliable features of the
+ * stack. Otherwise it guarantees that the stack trace is reliable.
+ *
+ * If the task is not 'current', the caller *must* ensure the task is inactive.
+ */
+int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
+ void *cookie, struct task_struct *task)
+{
+ struct unwind_state state;
+ unsigned long addr;
+
+ unwind_for_each_frame(&state, task, NULL, 0) {
+ if (state.stack_info.type != STACK_TYPE_TASK)
+ return -EINVAL;
+
+ if (state.regs)
+ return -EINVAL;
+
+ addr = unwind_get_return_address(&state);
+ if (!addr)
+ return -EINVAL;
+
+#ifdef CONFIG_KPROBES
+ /*
+ * Mark stacktraces with kretprobed functions on them
+ * as unreliable.
+ */
+ if (state.ip == (unsigned long)kretprobe_trampoline)
+ return -EINVAL;
+#endif
+
+ if (!consume_entry(cookie, addr, false))
+ return -EINVAL;
+ }
+
+ /* Check for stack corruption */
+ if (unwind_error(&state))
+ return -EINVAL;
+ return 0;
+}