Re: favourite vfs globals

[Pat LaVarre <p.lavarre@ieee.org>]

> Which vfs globals are the most fun, in lk like 2.6.0-test11?

That question I can't yet answer, but:

> gdb vmlinux /proc/kcore
> ... this approach to gdb takes a blurry snapshot of kernel memory and
> then walks us thru a stale copy of all the bits.

Also I suppose we can't see the global variables of modules this way,
except when the modules share those variables with non-module code i.e.
code linked into the kernel before boot.  I'm guessing wildly from
experiences like the following.

(gdb) info variables scsi_comm
All variables matching regular expression "scsi_comm":
 
File drivers/block/scsi_ioctl.c:
const unsigned char scsi_command_size[8];
static const char __kstrtab_scsi_command_size[18];
static const struct kernel_symbol __ksymtab_scsi_command_size;
(gdb) #
(gdb) print /x scsi_command_size
$2 = {0x6, 0xa, 0xa, 0xc, 0x10, 0xc, 0xa, 0xa}
(gdb) #
(gdb) file /lib/modules/2.6.0-11.udf/kernel/drivers/scsi/scsi_mod.ko
warning: core file may not match specified executable file.
Load new symbol table from
"/lib/modules/2.6.0-11.udf/kernel/drivers/scsi/scsi_mod.ko"? (y or n) y
 
Reading symbols from
/lib/modules/2.6.0-11.udf/kernel/drivers/scsi/scsi_mod.ko...done.
(gdb) #
(gdb) info variables xtime
...
(gdb) print xtime
Address of symbol "xtime" is unknown.
(gdb) #
(gdb) info variables scsi_command_size
...
(gdb) print scsi_command_size
Address of symbol "scsi_command_size" is unknown.
(gdb) #