Hi All, I was finally able to root cause the issue that I was facing in the kdump compressed output generated by makedumpfile. While debugging "write_kdump_pages_and_bitmap_cyclic"; I came to know that somehow "info->max_mapnr" was modified/ reduced. Seeing further, I could see that the "get_mem_map" function at the end [if (!is_xen_memory())] is attempting to change "info->max_mapnr" value based on "mem=" option. -- in particular commit ebe2fa3a5c1e2bfac3778c0fbeca4287a934cc58. And in my kernel command line, "mem=2G" was present, as I intended to take dump of 2G RAM, resulting into reduced "info->max_mapnr". So, I commented out this portion and confirmed that "info->max_mapnr" remains same throughout. And I was able to get kdump compressed vmcore process-able by crash utility. Just to summarize: Following was the problem statement: crash was giving "seek error" while makedumpfile generated kdump-compressed vmcore was getting analyzed. Details: > The output generated by makedumpfile gets processed by crash utility > if I use following command: > makedumpfile -E /proc/vmcore vmcore > > But, the output generated by following command (which I used while > reporting the issue) gives the "seek error" while being processed by > crash. > makedumpfile /proc/vmcore vmcore > > (As a result?), output from following command gives "seek error" as > well while being processed by crash: > makedumpfile -c /proc/vmcore vmcore Following is my setup details: >>> Kernel config: >>> ARM64_VA_BITS_48 [=y] >>> ARM64_PAGE_SHIFT [=12] >>> RANDOMIZE_BASE [=n] >>> ARM64_4K_PAGES [=y] > kernel: 4.12- rc5 > yocto based rootfs: Pyro[2.3] which has kexec 2.0.14 and makedumpfile 1.6.1. > crash: 7.1.9++ [Head: 4d517ad28acd845fe6e91360e645cf0446a4757b] Thanks, Abhishek
