From: Nicholas Piggin <npiggin@gmail.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
linux-kernel@vger.kernel.org,
Michael Ellerman <mpe@ellerman.id.au>
Subject: [PATCH] exit: Detect and fix irq disabled state in oops
Date: Tue, 4 Oct 2022 19:44:01 +1000 [thread overview]
Message-ID: <20221004094401.708299-1-npiggin@gmail.com> (raw)
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 <mpe@ellerman.id.au>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
kernel/exit.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/kernel/exit.c b/kernel/exit.c
index 84021b24f79e..fa696765f694 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -738,6 +738,7 @@ void __noreturn do_exit(long code)
struct task_struct *tsk = current;
int group_dead;
+ WARN_ON(irqs_disabled());
WARN_ON(tsk->plug);
kcov_task_exit(tsk);
@@ -865,6 +866,11 @@ 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),
--
2.37.2
next reply other threads:[~2022-10-04 9:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-04 9:44 Nicholas Piggin [this message]
2022-12-20 7:14 ` [PATCH] exit: Detect and fix irq disabled state in oops Nicholas Piggin
2022-12-24 4:28 ` Eric W. Biederman
2023-01-20 1:18 Nicholas Piggin
2023-01-20 15:21 ` Peter Zijlstra
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