From 001c28e57187570e4b5aa4492c7a957fb6d65d7b Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Fri, 20 Jan 2023 11:18:20 +1000 Subject: [PATCH] exit: Detect and fix irq disabled state in oops If a task oopses with irqs disabled, this can cause various cascading problems in the oops path such as sleep-from-invalid warnings, and potentially worse. Since commit 0258b5fd7c712 ("coredump: Limit coredumps to a single thread group"), the unconditional irq enable in coredump_task_exit() will "fix" the irq state to be enabled early in do_exit(), so currently this may not be triggerable, but that is coincidental and fragile. Detect and fix the irqs_disabled() condition in the oops path before calling do_exit(), similarly to the way in_atomic() is handled. Reported-by: Michael Ellerman Signed-off-by: Nicholas Piggin Signed-off-by: Peter Zijlstra (Intel) Acked-by: "Eric W. Biederman" Link: https://lore.kernel.org/lkml/20221004094401.708299-1-npiggin@gmail.com/ --- kernel/exit.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/exit.c b/kernel/exit.c index 15dc2ec80c46..bccfa4218356 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -807,6 +807,8 @@ void __noreturn do_exit(long code) struct task_struct *tsk = current; int group_dead; + WARN_ON(irqs_disabled()); + synchronize_group_exit(tsk, code); WARN_ON(tsk->plug); @@ -938,6 +940,11 @@ void __noreturn make_task_dead(int signr) if (unlikely(!tsk->pid)) panic("Attempted to kill the idle task!"); + if (unlikely(irqs_disabled())) { + pr_info("note: %s[%d] exited with irqs disabled\n", + current->comm, task_pid_nr(current)); + local_irq_enable(); + } if (unlikely(in_atomic())) { pr_info("note: %s[%d] exited with preempt_count %d\n", current->comm, task_pid_nr(current),