x86/dumpstack: Pin the target stack when dumping it

[cascardo/linux.git] / arch / x86 / kernel / stacktrace.c

diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index 785aef1..23fa81e 100644 (file)
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -79,9 +79,14 @@ void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
 
 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 {
+       if (!try_get_task_stack(tsk))
+               return;
+
        dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);
        if (trace->nr_entries < trace->max_entries)
                trace->entries[trace->nr_entries++] = ULONG_MAX;
+
+       put_task_stack(tsk);
 }
 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);