On Wed, Jan 11, 2006 at 03:48:06AM -0800, tanu wrote:
> when we open mdb with -K option i.e. kmdb, and set a breakpoint
> without specifying an address, whats the expected behaviour. Will the
> system panic?
>
> If we set the breakpoint in data segment ex:
> [0]> page_hash/J
> page_hash:
> page_hash: 1a24000
> [0]> :b
> [0]> :c
>
> the system panics. Is this the expected behaviour. Shouldn't mdb
> should give an error on this. Is there a document available indicating
> system behaviour when a breakpoint is set without an address.
When given no explicit value, the legacy ADB commands (such a :b) take
the value of 'dot' from the last command run. For example:
$ mdb
> 5=K
5
> :b
> ::events
ID S TA HT LM Description Action
----- - -- -- -- ---------------------------------------- ----------------------
[ 1 ] - 0 0 stop at 5 -
>
This is necessary for ADB compatbility. So in your above example, you
set a breakpoint at 0x1a24000 (obvbiously a very bad thing). If you use
the mdb dcmd version (::bp), it will rightly complain that no address
was given:
$ mdb
> 5=K
5
> ::bp
Usage: [address]::bp [+/-dDestT] [-c cmd] [-n count] sym ...
mdb: try '::help bp' for more information
> 5::bp
>
Hope that helps.
- Eric
--
Eric Schrock, Solaris Kernel Development http://blogs.sun.com/eschrock
