On Mon, 19 Apr 2004 19:50:08 +0500,
Ananth N Mavinakayanahalli <[EMAIL PROTECTED]> wrote:
>Hi,
>
>While working on KDB for ppc64, I hit a race in kdb(). Verified that the
>problem exists on x86 too..
>
>Problem occurs when a bp is set on a very frequently hit routine (eg.,
>sys_read() or schedule()), and multiple processors hit the bp
>simultaneously. This is the problem I am seeing...
>
> CPU0 CPU1
> | |
> kdb(reason = break) |
> | |
> | |
> spin_lock() |
> | |
> kdb_initial_cpu = 0; |
> | |
> spin_unlock() |
> .. kdb(reason = break)
> | |
> | if (reason != KDB_REASON_SWITCH) {
> | if (KDB_IS_RUNNING() && !KDB_STATE(REENTRY))
> | <is true>
> | ....
> |
> |
> smp_kdb_stop();
I know. Fixing this trace requires significant changes to the way that
breakpoints are handled and will break kdb for all architectures. It
is on my list for kdb v5.0.
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