Re: Broken kretprobe stack traces

[Daniel Xu]

On Wed, Mar 03, 2021 at 03:37:40PM -0500, Steven Rostedt wrote:
> On Wed, 03 Mar 2021 12:13:08 -0800
> "Daniel Xu" <dxu@xxxxxxxxx> wrote:
> 
> > On Wed, Mar 3, 2021, at 11:58 AM, Daniel Xu wrote:
> > > On Wed, Mar 03, 2021 at 09:26:04AM -0500, Steven Rostedt wrote:  
> > > > On Wed, 3 Mar 2021 13:48:28 +0900
> > > > Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:
> > > >   
> > > > >   
> > > > > > 
> > > > > > I think (can't prove) this used to work:    
> > > > 
> > > > Would be good to find out if it did.  
> > > 
> > > I'm installing some older kernels now to check. Will report back.  
> > 
> > Yep, works in 4.11. So there was a regression somewhere.
> 
> Care to bisect? ;-)

Took a while (I'll probably be typing "test_regression.sh" in my sleep
tonight) but I've bisected it down to f95b23a112f1 ("Merge branch
'x86/urgent' into x86/asm, to pick up dependent fixes").

I think I saw the default option for stack unwinder change from frame
pointers -> ORC so that may be the root cause. Not sure, though. Need to
look more closely at the commits in the merge commit.

<...>

Daniel