Re: [Crash-utility] Broken vtop on kernel 2.6.20?

On Tue, 2007-05-29 at 15:45 -0400, David Anderson wrote: >Alex Sidorenko wrote: > >>Hi Dave, >> >>when I try to use 'vtop' for process pages on 2.6.20 kernel (Ubuntu/Feisty) on >>x86 architecture, I get error messages about page table. The easiest way to >>reproduce is to run 'ps -a' on a live kernel: >> >> >>PID: 0 TASK: c03a2440 CPU: 0 COMMAND: "swapper" >>ps: no user stack >> >>PID: 0 TASK: df838560 CPU: 1 COMMAND: "swapper" >>ps: no user stack >> >>PID: 1 TASK: df838a90 CPU: 1 COMMAND: "init" >>ps: read error: physical address: 7f2f0000 type: "page table" >> >> >>Running crash with -d8: >> >>PID: 1 TASK: df838a90 CPU: 1 COMMAND: "init" >><readmem: df838a90, KVADDR, "fill_task_struct", 1328, (ROE|Q), 8d2eac0> >><readmem: dfb71e40, KVADDR, "fill_mm_struct", 432, (ROE|Q), 8d8bf80> >> GETBUF(128 -> 1) >> FREEBUF(1) >> GETBUF(128 -> 1) >> FREEBUF(1) >> GETBUF(128 -> 1) >> FREEBUF(1) >> GETBUF(128 -> 1) >> FREEBUF(1) >>arg_start: bf991ecf arg_end: bf991ee1 (18) >>env_start: bf991ee1 env_end: bf991ff1 (272) >> GETBUF(291 -> 1) >><readmem: dfb6f000, KVADDR, "pgd page", 4096, (FOE), 843cf90> >><readmem: dfb6f000, KVADDR, "pmd page", 4096, (FOE), 843cf90> >><readmem: 7f2f0000, PHYSADDR, "page table", 4096, (FOE), 843efa0> >>ps: read error: physical address: 7f2f0000 type: "page table" >> >>The same crash-4.0-4.1 works fine on live 2.6.15 kernel. Did the page table >>layout change between 2.6.15 and 2.6.20 ? >> >>Regards, >>Alex >> >I don't know. I don't have an x86 2.6.20 live system or dumpfile >readily available, >so I'll need some help from the "outside world" here... > >Anybody else know anything about this? > On a 2.6.21 kernel with the -rt patchset, and crash-4.0-4.1, I see some of this: PID: 3093 TASK: f69793b0 CPU: 0 COMMAND: "mingetty" ps: cannot access user stack address: bf9fdf4c PID: 3094 TASK: f7f2abf0 CPU: 0 COMMAND: "mingetty" ps: cannot access user stack address: bfbb2f4c on i686 but I haven't seen it on x86_64. (Dave, I have these kernels, and systems with these kernels, you can access if you wish) --Guy