[Crash-utility] new printk ringbuffer interface

Hello Dave, You may or may not be aware that we are working on replacing [0] the Linux printk ringbuffer. Rather than a single buffer containing a single struct type, the new ringbuffer makes use of several different structs. I am writing to ask your advice about how this should be exported for the crash utility. Should all struct sizes and field offsets be exported? It would look something like this: VMCOREINFO_SYMBOL(prb); VMCOREINFO_STRUCT_SIZE(printk_ringbuffer); VMCOREINFO_OFFSET(printk_ringbuffer, desc_ring); VMCOREINFO_OFFSET(printk_ringbuffer, text_data_ring); VMCOREINFO_OFFSET(printk_ringbuffer, dict_data_ring); VMCOREINFO_OFFSET(printk_ringbuffer, fail); VMCOREINFO_STRUCT_SIZE(prb_desc_ring); VMCOREINFO_OFFSET(prb_desc_ring, count_bits); VMCOREINFO_OFFSET(prb_desc_ring, descs); VMCOREINFO_OFFSET(prb_desc_ring, head_id); VMCOREINFO_OFFSET(prb_desc_ring, tail_id); VMCOREINFO_STRUCT_SIZE(prb_desc); VMCOREINFO_OFFSET(prb_desc, info); VMCOREINFO_OFFSET(prb_desc, state_var); VMCOREINFO_OFFSET(prb_desc, text_blk_lpos); VMCOREINFO_OFFSET(prb_desc, dict_blk_lpos); VMCOREINFO_STRUCT_SIZE(prb_data_blk_lpos); VMCOREINFO_OFFSET(prb_data_blk_lpos, begin); VMCOREINFO_OFFSET(prb_data_blk_lpos, next); VMCOREINFO_STRUCT_SIZE(printk_info); VMCOREINFO_OFFSET(printk_info, seq); VMCOREINFO_OFFSET(printk_info, ts_nsec); VMCOREINFO_OFFSET(printk_info, text_len); VMCOREINFO_OFFSET(printk_info, dict_len); VMCOREINFO_OFFSET(printk_info, caller_id); VMCOREINFO_STRUCT_SIZE(prb_data_ring); VMCOREINFO_OFFSET(prb_data_ring, size_bits); VMCOREINFO_OFFSET(prb_data_ring, data); VMCOREINFO_OFFSET(prb_data_ring, head_id); VMCOREINFO_OFFSET(prb_data_ring, tail_id); Or would it be enough to just recognize the new "prb" symbol and have all the structures defined in the crash utility? If the latter is preferred, should some sort of version number be exported? Or is the kernel version number enough? I appreciate your feedback. John Ogness [0] lkml.kernel.org/r/20200128161948.8524-1-john.ogness@linutronix.de