Messages in this thread Patch in this message | | | From | Nicholas Piggin <> | Subject | [PATCH] exit: Detect and fix irq disabled state in oops | Date | Fri, 20 Jan 2023 11:18:20 +1000 |
| |
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.
Link: https://lore.kernel.org/lkml/20221004094401.708299-1-npiggin@gmail.com/ Reported-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- Hi Peter,
Would you consider taking this through the sched tree?
Thanks, Nick
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), -- 2.37.2
| |