lkml.org 
[lkml]   [2002]   [Jul]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: simple handling of module removals Re: [OKS] Module removal
Hi,

On Thu, Jul 04, 2002 at 01:48:59AM +0200, Daniel Phillips
<phillips@arcor.de> wrote:

> Is it just the mod_dec_use_count; return/unload race we're worried about?
> I'm not clear on why this is hard. I'd think it would be sufficient just to
> walk all runnable processes to ensure none has an execution address inside the
> module.

That fails if:

the module function has called somewhere else in the kernel (and
with -fomit-frame-pointer, you can't reliably walk back up the stack
to find out if there is a stack frame higher up the stack which is in
the module);

the module has taken an interrupt into an unrelated driver;

we have computed a call into the module but haven't actually executed
the call yet;

etc.


> For smp, an ipi would pick up the current process on each cpu.

Without freezing the other CPUs, that still leaves the race wide open.

--Stephen
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:22    [W:0.054 / U:0.096 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site