Messages in this thread |  | | Date | Fri, 25 May 2001 08:07:40 -0400 | From | Brian Gerst <> | Subject | Re: [CHECKER] large stack variables (>=1K) in 2.4.4 and 2.4.4-ac8 |
| |
Andi Kleen wrote: > > On Fri, May 25, 2001 at 07:52:02AM -0400, Brian Gerst wrote: > > Actually, you will never get a stack fault exception, since with a flat > > stack segment you can never get a limit violation. All you will do is > > corrupt the data in task struct and cause an oops later on when the > > kernel tries to use the task struct. There are only two ways to > > properly trap a kernel stack overflow: > > In my experience the stack pointer eventually gets corrupted and starts > pointing to some unmapped area, which gives you a stack fault (admittedly > a backtrace is a bit hard after that)
You mean a double fault. #SS is only called when there is a limit violation on the stack segment or the stack segment is not present. I guess you could get a limit violation if it tried to wrap around below 0, but you would get a page fault first. An unmapped page will always cause a page fault, but since the stack is still invalid, it would then cause a double fault.
--
Brian Gerst - 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/
|  |