Currently, show_stack() always dumps the trace of the current task.
However, it should dump the trace of the specified task if one is
provided. Otherwise, things like running "echo t > sysrq-trigger"
won't work as expected.

Fixes: 970e51feaddb ("um: Add support for CONFIG_STACKTRACE")
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
---
 arch/um/kernel/sysrq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/um/kernel/sysrq.c b/arch/um/kernel/sysrq.c
index 4bb8622dc512..e3b6a2fd75d9 100644
--- a/arch/um/kernel/sysrq.c
+++ b/arch/um/kernel/sysrq.c
@@ -52,5 +52,5 @@ void show_stack(struct task_struct *task, unsigned long *stack,
 	}
 
 	printk("%sCall Trace:\n", loglvl);
-	dump_trace(current, &stackops, (void *)loglvl);
+	dump_trace(task ?: current, &stackops, (void *)loglvl);
 }
-- 
2.34.1