On Tue, 7 May 2019 23:13:40 +0900 Masami Hiramatsu mhiramat@kernel.org wrote:
On Mon, 6 May 2019 17:45:11 -0400 Steven Rostedt rostedt@goodmis.org wrote:
If we go with Peter's patch, I can make this code much more sane, and not have to worry about having ®s->sp be at the top of the stack. I could simply, just push everything in the order of pt_regs and call the handler.
Hi Steve, I need to catch up with the origin of this series, but it seems also good to optprobe which is doing similar trick on pt_regs. If we can assume that int3 pt_regs can have a gap, optprobe can also make a gap, and it can be also used for storing destination address.
Sorry, I misunderstood. I see the issue ( https://lkml.org/lkml/2019/5/1/497 ) and solutions on the thread. If we really need to fix this trace-livepatch combination issue, it may be good to backport to stable trees.
From this viewpoint, Linus's suggestion (no pt_reg changes on x86-32) seems
to have a point.
BTW, even though I think Peter's patch (unifying pt_regs behavior) will also be good for us for more general reason (not only for fixing actual issue).
Thank you,