Hello Ethan, On Wed, Aug 06, 2025 at 09:55:05AM +0800, Ethan Zhao wrote: > On 8/4/2025 5:17 PM, Breno Leitao wrote: > > Similarly to pci_dev_aer_stats_incr(), pci_print_aer() may be called > > when dev->aer_info is NULL. Add a NULL check before proceeding to avoid > > calling aer_ratelimit() with a NULL aer_info pointer, returning 1, which > > does not rate limit, given this is fatal. > > > > This prevents a kernel crash triggered by dereferencing a NULL pointer > > in aer_ratelimit(), ensuring safer handling of PCI devices that lack > > AER info. This change aligns pci_print_aer() with pci_dev_aer_stats_incr() > > which already performs this NULL check. > > > The enqueue side has lock to protect the ring, but the dequeue side no lock > held. > > The kfifo_get in > static void aer_recover_work_func(struct work_struct *work) > { > ... > while (kfifo_get(&aer_recover_ring, &entry)) { > ... > } > should be replaced by > kfifo_out_spinlocked()
The design seems not to need the lock on the reader side. There is just one reader, which is the aer_recover_work. aer_recover_work runs aer_recover_work_func(). So, if we just have one reader, we do not need to protect the kfifo by spinlock, right? In fact, the code documents it in the aer_recover_ring_lock. /* * Mutual exclusion for writers of aer_recover_ring, reader side don't * need lock, because there is only one reader and lock is not needed * between reader and writer. */ static DEFINE_SPINLOCK(aer_recover_ring_lock);