On 4/24/25 8:51 PM, Ming Lei wrote: > Both adding/deleting disk code are reader of `nr_hw_queues`, so we can't > allow them in-progress when updating nr_hw_queues, kernel panic and > kasan has been reported in [1]. > > Prevent adding/deleting disk during updating nr_hw_queues by adding > rw_semaphore to tagset, write lock is grabbed in blk_mq_update_nr_hw_queues(), > and read lock is acquired when adding/deleting disk. > > Also mark GFP_NOIO allocation scope for adding/deleting disk because > blk_mq_update_nr_hw_queues() is part of some driver's error handler. > > This way avoids lot of trouble. > > Suggested-by: Nilay Shroff <nilay@xxxxxxxxxxxxx> > Reported-by: Nilay Shroff <nilay@xxxxxxxxxxxxx> > Closes: https://lore.kernel.org/linux-block/a5896cdb-a59a-4a37-9f99-20522f5d2987@xxxxxxxxxxxxx/ > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> Looks good to me: Reviewed-by: Nilay Shroff <nilay@xxxxxxxxxxxxx>
