On Fri, 2010-01-22 at 12:54 +0530, Ananth N Mavinakayanahalli wrote: > On Fri, Jan 22, 2010 at 12:32:32PM +0530, Srikar Dronamraju wrote: > > Here is a summary of the Comments and actions that need to be taken for > > the current uprobes patchset. Please let me know if I missed or > > misunderstood any of your comments. > > > > 1. Uprobes depends on trap signal. > > Uprobes depends on trap signal rather than hooking to the global > > die notifier. It was suggested that we hook to the global die notifier. > > > > In the next version of patches, Uprobes will use the global die > > notifier and look at the per-task count of the probes in use to > > see if it has to be consumed. > > > > However this would reduce the ability of uprobe handlers to > > sleep. Since we are dealing with userspace, sleeping in handlers > > would have been a good feature. We are looking at ways to get > > around this limitation. > > We could set a TIF_ flag in the notifier to indicate a breakpoint hit > and process it in task context before the task heads into userspace.
OK, so we can go play stack games in the INT3 interrupt handler by moving to a non IST stack when it comes from userspace, or move kprobes over to INT1 or something.