----- Original Message ----- > > That seems to be a bug (?), but it's not particularly important, > > because for x86 and x86_64, the data in the NT_PRSTATUS notes is > > only used if the starting point for backtraces if the PC/SP pair > > cannot be determined otherwise, which is the case virtually all of > > the time. So the registers found in the NT_PRSTATUS notes are > > pretty much useless... > > I seem to be minor bug, if some of cpus are offline while panic, > can't backtrace the same number of cpus from tail because of returning NULL. > I think current task's PC/SP can not obtain from thread_struct corectly, > then NT_PRSTATUS notes need to be stored for them instead. For the active tasks, the PC/SP starting points can typically be found by looking at the stack contents. The NT_PRSTATUS notes are a relatively recent addition to compressed kdumps, i.e., have only existed since header version 4. Only in very rare circumstances do the x86 and x86_64 arches need to utilize the registers in the compressed kdump NT_PRSTATUS notes. That being said, I will fix the invalid value that is stored in dd->num_prstatus_notes so that diskdump_get_prstatus_percpu() will work as expected if there are offline cpus. That function is currently used only by x86 and x86_64, so there should be no issues with the other arches. > Yes I'm going to rework, and thanks for your reviews. > I'm modifying difficult parts this time, very helpful. > > I'll do more tests before sending reworked PPC only patch. > I also have to study about kexectools or makedumpfile more about > how NT_PRSTATUS or others are treated, haven't understood enough. OK thanks, Dave -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility