On Thu, Dec 06, 2018 at 10:35:28AM -0500, Vince Weaver wrote: > On Wed, 5 Dec 2018, Jiri Olsa wrote: > > > On Wed, Dec 05, 2018 at 12:11:19PM -0500, Vince Weaver wrote: > > > On Wed, 5 Dec 2018, Jiri Olsa wrote: > > > > > > > On Wed, Dec 05, 2018 at 01:45:38PM +0100, Jiri Olsa wrote: > > > > > On Tue, Dec 04, 2018 at 10:54:55AM -0500, Vince Weaver wrote: > > > > > > Hello, > > > > > > > > > > > > I was able to trigger another oops with the perf_fuzzer with > > > > > > current git. > > > > > > > > > > > > This is 4.20-rc5 after the fix for the very similar oops I > > > > > > previously > > > > > > reported got committed. > > > > > > > > > > > > It seems to be pointing to the same location in the source as > > > > > > before, I guess maybe triggered a different way? > > > > > > > > > > nice.. yep, looks the same > > > > > > > > > > > > > > > > > Unfortunately this crash is not easily reproducible like the last > > > > > > one was. > > > > > > > > > > will check > > > > > > > > what model are hitting this on? > > > > > > Haswell. 6/60/3. > > > > > > While I can't deterministically trigger this, the fuzzer usually hits it > > > within an hour or two. Is there any debug or printk messages I can > > > add that would help figure out what's going on? > > > > I can't see how we could end up with that config other than > > some corruption.. the only way I see could be that we touch > > cpu->events array without checking its active_mask bit > > > > but that does not explain why the crash happened in the same > > place as before > > Maybe it is a corruption issue. I had applied my own debug patch that > would dump some info if data->callchain was NULL. > > But my debug code didn't trigger this time because it looks like > data->callchain was "1" rather than "0". > > [27764.840179] BUG: unable to handle kernel NULL pointer dereference at > 0000000000000001 > [27764.840179] PGD 0 P4D 0 > [27764.840180] Oops: 0000 [#1] SMP PTI > [27764.840180] CPU: 1 PID: 18687 Comm: perf_fuzzer Tainted: G W > 4.20.0-rc5+ #125 > [27764.840180] Hardware name: LENOVO 10AM000AUS/SHARKBAY, BIOS FBKT72AUS > 01/26/2014
actually, you could try that patch from my previous email? thanks, jirka
