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authorNicholas Piggin <npiggin@gmail.com>2023-01-20 11:18:20 +1000
committerPeter Zijlstra <peterz@infradead.org>2023-01-21 00:06:10 +0100
commit001c28e57187570e4b5aa4492c7a957fb6d65d7b (patch)
tree5c3529c190649f91ed01c32728e2a1ffe237ef11 /kernel/exit.c
parent19235e47279894b033a3ec5cf2732de634862b3a (diff)
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 <mpe@ellerman.id.au> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Link: https://lore.kernel.org/lkml/20221004094401.708299-1-npiggin@gmail.com/
Diffstat (limited to 'kernel/exit.c')
-rw-r--r--kernel/exit.c7
1 files changed, 7 insertions, 0 deletions
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),