On 1/23/18 10:20 AM, Eryu Guan wrote: > Attributes that only implement .seq_ops are read-only, any write to > them should be rejected. But currently kernel would crash when > writing to such debugfs entries, e.g. > > chmod +w /sys/kernel/debug/block/<dev>/requeue_list > echo 0 > /sys/kernel/debug/block/<dev>/requeue_list > chmod -w /sys/kernel/debug/block/<dev>/requeue_list > > Fix it by returning -EPERM in blk_mq_debugfs_write() when writing to > such attributes. I don't particularly like the fix, since it's not really clear why that comparison makes sense. Can't we just prevent anyone from making the debugfs entries writable? Seems like a much more sane approach. -- Jens Axboe
