signals, debug: fix BUG: using smp_processor_id() in preemptible code in print_fatal_signal()
With print-fatal-signals=1 on a kernel with CONFIG_PREEMPT=y, sending an
unexpected signal to a process causes a BUG: using smp_processor_id() in
preemptible code.
get_signal_to_deliver() releases the siglock before calling
print_fatal_signal(), which calls show_regs(), which calls
smp_processor_id(), which is not supposed to be called from a
preemptible thread.
Make sure show_regs() runs with preemption disabled.
Signed-off-by: Ed Swierk <eswierk@aristanetworks.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/signal.c b/kernel/signal.c
index e737597..b6b3676 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -909,7 +909,9 @@
}
#endif
printk("\n");
+ preempt_disable();
show_regs(regs);
+ preempt_enable();
}
static int __init setup_print_fatal_signals(char *str)