Re: 6.0_BETA: uvm_fault, kernfs_readdir

[Petar Bogdanovic <petar%smokva.net@localhost>]

On Sat, Mar 17, 2012 at 09:35:30PM +0100, Petar Bogdanovic wrote:
>
>       uvm_fault(0xfffffe8114c4dbd0, 0x0, 1) -> e
>       fatal page fault in supervisor mode
>       trap type 6 code 0 rip ffffffff804f4ceb cs 8 rflags 10297 cr2  0 cpl 0
>       rsp fffffe80016077a0
>       kernel: page fault trap, code=0
>       Stopped in pid 847.1 (find) at  netbsd:kernfs_readdir+0x687:    movq
>       7fb0b30e
>       (%rip),%rdi
>       db{1}> bt
>       kernfs_readdir() at netbsd:kernfs_readdir+0x687
>       VOP_READDIR() at netbsd:VOP_READDIR+0x65
>       vn_readdir() at netbsd:vn_readdir+0xf6
>       sys___getdents30() at netbsd:sys___getdents30+0x76
>       syscall() at netbsd:syscall+0xc4


Probably unrelated but worth mentioning:  The same situation yields a
slightly different result when ddb.onpanic=0 and ends with what seems
to be a complete meltdown after the core was successfully dumped:

        uvm_fault(0xfffffe811556ad40, 0x0, 1) -> e
        fatal page fault in supervisor mode
        trap type 6 code 0 rip ffffffff804f4ceb cs 8 rflags 10297 cr2  0 cpl 0 
rsp fffffe80015b77a0
        panic: trap
        cpu1: Begin traceback...
        printf_nolog() at netbsd:printf_nolog
        startlwp() at netbsd:startlwp
        alltraps() at netbsd:alltraps+0xa2
        VOP_READDIR() at netbsd:VOP_READDIR+0x65
        vn_readdir() at netbsd:vn_readdir+0xf6
        sys___getdents30() at netbsd:sys___getdents30+0x76
        syscall() at netbsd:syscall+0xc4
        cpu1: End traceback...

        (..dump begins, finishes..)

        pmap_kenter_pa: mapping already present
        pmap_kenter_pa: mapping already present
        pmap_kenter_pa: mapping already present

        (..many, many more identical lines..)
        (..takes as long as the core dump..)

        pmap_kenter_pa: mapping already present
        pmap_kenter_pa: mapping already present
        pmap_kenter_pa: mapping already present
        succeeded
                

        Skipping crash dump on recursive panic
        panic: wdc_exec_command: polled command not done
        cpu1: Begin traceback...
        printf_nolog() at netbsd:printf_nolog
        wdccommand() at netbsd:wdccommand
        wd_flushcache() at netbsd:wd_flushcache+0xd7
        wd_shutdown() at netbsd:wd_shutdown+0x3e
        pmf_system_shutdown() at netbsd:pmf_system_shutdown+0x81
        cpu_reboot() at netbsd:cpu_reboot+0x2c
        vpanic() at netbsd:vpanic+0x1dd
        printf_nolog() at netbsd:printf_nolog
        startlwp() at netbsd:startlwp
        alltraps() at netbsd:alltraps+0xa2
        VOP_READDIR() at netbsd:VOP_READDIR+0x65
        vn_readdir() at netbsd:vn_readdir+0xf6
        sys___getdents30() at netbsd:sys___getdents30+0x76
        syscall() at netbsd:syscall+0xc4
        cpu1: End traceback...
        rebooting...