* Frank Ch. Eigler <f...@redhat.com> wrote: > Hi - > > On Sun, Mar 22, 2009 at 01:37:59AM +0300, Alexey Dobriyan wrote: > > [...] > > struct task_struct::utrace became embedded struct. This is good and > > should remove quite a few of utrace bugs. Better late than never. > > Yeah. > > > However, "rewrite-ptrace-via-utrace" patch was omitted, so > > almost noone can easily see by how much situation improved. > > [...] Will ptrace(2) will be rewritten through utrace? > > Yes, I believe that is Roland's intent. I believe it was > separated from the current suite of patches for staging purposes, > to merge the most solid code up first. The code is available from > the utrace git tree in the utrace-ptrace branch.
i think they should be submitted together. Here's the histogram of utrace bugs on kerneloops.org: 2.6.27.5 1 x 2.6.27.15 1 x 2.6.27.12 2 x 2.6.27-rc4 2 x 2.6.26.6 1 x 2.6.26.5 43 x 2.6.26.3 1102 x 2.6.26.2 2 x 2.6.26.1 3 x 2.6.26 1 x 2.6.25 3 x That peak in 2.6.26.3 is what i referred to. The latest F10 kernel rpm is kernel-2.6.27.12-170.2.5.fc10, and it does include the utrace-ptrace engine as well: # grep UTRACE /boot/config-2.6.27.19-170.2.35.fc10.i686 CONFIG_UTRACE=y CONFIG_UTRACE_PTRACE=y So the bug i referred to was fixed and the bug count has gone down - but still we have the utrace core submission here without any (tested) mainline kernel usage of the core code. My suggestion would be to: - submit the ptrace-on-utrace engine as well (with Oleg's signoff?) - perhaps also submit with a well-tested ftrace plugin that tries to utilize _all_ aspects of utrace and ftrace (and hence gives good and continuous burn-in testing via the ftrace bootup self-tests, etc.) ideally we want both, because: - tracing corner-case bugs tend to be found much faster than ptrace corner case bugs - partly because tracing is much more invasive when activated system-wide. - ptrace-over-utrace on the other hand utilizes utrace more deeply than passive tracing ever can. (for example UML does full, active virtualization via ptrace - this depth of functional utrace usage is not possible via a tracing plugin.) And i think the ptrace-via-utrace engine is actually fully ready, just perhaps it was not submitted out of caution to keep the logistics simple. So i do think we've still got a shot at merging it, in this merge window. Ingo