| Message ID | 20221026134830.711887-1-bigeasy@linutronix.de (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: multi-gen LRU: Move lru_gen_add_mm() out of IRQ-off region. | expand |
On Wed, Oct 26, 2022 at 7:49 AM Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote: > > lru_gen_add_mm() has been added within an IRQ-off region in the commit > mentioned below. The other invocations of lru_gen_add_mm() are not within > an IRQ-off region. > The invocation within IRQ-off region is problematic on PREEMPT_RT > because the function is using a spin_lock_t which must not be used > within IRQ-disabled regions. > > The other invocations of lru_gen_add_mm() occur while task_struct::alloc_lock > is acquired. > Move lru_gen_add_mm() after interrupts are enabled and before > task_unlock(). > > Fixes: bd74fdaea1460 ("mm: multi-gen LRU: support page table walks") > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Thanks. Acked-by: Yu Zhao <yuzhao@google.com>
--- a/fs/exec.c +++ b/fs/exec.c @@ -1012,7 +1012,6 @@ static int exec_mmap(struct mm_struct *m active_mm = tsk->active_mm; tsk->active_mm = mm; tsk->mm = mm; - lru_gen_add_mm(mm); /* * This prevents preemption while active_mm is being loaded and * it and mm are being updated, which could cause problems for @@ -1025,6 +1024,7 @@ static int exec_mmap(struct mm_struct *m activate_mm(active_mm, mm); if (IS_ENABLED(CONFIG_ARCH_WANT_IRQS_OFF_ACTIVATE_MM)) local_irq_enable(); + lru_gen_add_mm(mm); task_unlock(tsk); lru_gen_use_mm(mm); if (old_mm) {
lru_gen_add_mm() has been added within an IRQ-off region in the commit mentioned below. The other invocations of lru_gen_add_mm() are not within an IRQ-off region. The invocation within IRQ-off region is problematic on PREEMPT_RT because the function is using a spin_lock_t which must not be used within IRQ-disabled regions. The other invocations of lru_gen_add_mm() occur while task_struct::alloc_lock is acquired. Move lru_gen_add_mm() after interrupts are enabled and before task_unlock(). Fixes: bd74fdaea1460 ("mm: multi-gen LRU: support page table walks") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- fs/exec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)