----- "Dave Anderson" <anderson at redhat.com> wrote: > ----- "Neil Horman" <nhorman at redhat.com> wrote: > > > On Sat, Oct 10, 2009 at 10:56:32AM +0800, CAI Qian wrote: > > > Hallo! > > > > > > The crash utility failed to initialize when read the VMCore from > > > makedumpfile -d 2. > > > > > > # crash -d 7 vmlinux vmcore.2 > > > > > > <readmem: ffffffff818ba450, KVADDR, "__per_cpu_offset", 32768, (FOE), a31fc8> > > > GNU_GET_DATATYPE[runqueue]: returned via gdb_error_hook (1 buffer i use) > > > GNU_GET_DATATYPE[runqueue]: returned via gdb_error_hook (1 buffer in use) > > > GNU_GET_DATATYPE[prio_array]: returned via gdb_error_hook (1 buffer in use) > > > GNU_GET_DATATYPE[prio_array]: returned via gdb_error_hook (1 buffer in use) > > > GNU_GET_DATATYPE[prio_array]: returned via gdb_error_hook (1 buffer in use) > > > <readmem: ffff88000c60e2f8, KVADDR, "cpu number (per_cpu)", 4, (FOE), 7fff04f30c1c> > > > <readmem: ffff88000c7ed2f8, KVADDR, "cpu number (per_cpu)", 4, (FOE), 7fff04f30c1c> > > > <readmem: ffffffff818d92f8, KVADDR, "cpu number (per_cpu)", 4, (FOE), 7fff04f30c1c> > > > crash: page excluded: kernel virtual address: ffffffff818d92f8 type: "cpu number (per_cpu)" > > -d 2 is exclude cached pages, I don't rightly see how any of these data structures > > can be in pagecache. Not sure if that means that makedumpfile filtered them > > inappropriately, or if crash is looking for them in the wrong place. > > > > Neil > > Given that the full vmcore shows that there are 2 cpus, and that the > failure above is on an attempt to read/verify a 3rd cpu, it's pretty > clear that this is a crash bug. There have been a few of these type > of bugs that have recently been discovered due to the movement of the > the x8664_pda data structures to per-cpu data variables in 2.6.30. > Unfortunately, the x86_64_per_cpu_init() is trying to figure out > how many cpus are there, and it's currently doing a "read-and-verify" > kind of thing, but will need to be changed to recognize a readmem failure > as the end of the line. > > I'll be back on Tuesday -- Cai, can you contact me offline and > make the vmcore/vmlinux pair available? This will be fixed in the next upstream crash utility release. In the meantime, "page excluded" errors can be worked around by using the --zero_excluded command line option, as in: # crash --zero_excluded vmlinux vmcore.2 Dave
