Re: Recovery kernel and application crashes how?
Carl van Schaik <[email protected]>
| Newsgroups | gmane.comp.micro-kernel.l4.l4ka.general |
|---|---|
| Organization | Open Kernel Labs |
| Message-ID | <[email protected]> |
Hi Prem, 1. A thread accessing memory that is not mapped or does not have suitable permissions generates a pagefault. Pagefaults are delivered on behalf of the thread to that threads "pager", a different thread setup to handle these. The page may then perform operations to map pages to the thread's address space or kill the thread etc. 2. Drivers in L4 are typically servers or libraries run at user level, thus a driver faulting has the same behavior as above. The L4 kernel is small and thus it is easier to prevent kernel bugs. L4Ka does not handle kernel faults such as null pointer dereferences, like many kernels, it is not recoverable. 3. Threads can only access memory in their own address space, it is not possible for a thread to access a different address space. If no mappings exist at am attempted address, a pagefault is generated as in 1 above. regards, Carl [email protected] wrote: > Date: Thu, 10 May 2007 09:19:02 +0530 > From: "Prem Mallappa" <[email protected]> > Subject: Recovery kernel and application crashes how? > To: [email protected] > Message-ID: > <[email protected]> > Content-Type: text/plain; charset="iso-8859-1" > > Hi All, > I am interested to know the behaviour of L4Ka in the following conditions. > > 1. Thread (or task) trying to access unmapped memory (null pointer > dereference) > 2. Kernel/driver trying to access unmapped memory (null pointer dereference) > 3. Thread (or task) trying to access memory mapped to other process (may not > holds good for l4 since each thread has its own address space). > > And how the recover from such exceptions(errors) are done. > > Thanks > Prem > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: http://lists.ira.uni-karlsruhe.de/pipermail/l4ka/attachments/20070510/cf306f16/attachment-0001.html > > ------------------------------ > > _______________________________________________ > l4ka mailing list > [email protected] > https://lists.ira.uni-karlsruhe.de/mailman/listinfo/l4ka > > > End of l4ka Digest, Vol 41, Issue 1 > *********************************** >