On 10/19/21 4:21 PM, Guillaume Tucker wrote: > Hi Jens, > > On 17/10/2021 02:37, Jens Axboe wrote: >> Add an rq private RQF_ELV flag, which tells the block layer that this >> request was initialized on a queue that has an IO scheduler attached. >> This allows for faster checking in the fast path, rather than having to >> deference rq->q later on. >> >> Elevator switching does full quiesce of the queue before detaching an >> IO scheduler, so it's safe to cache this in the request itself. > > A kernelci.org automated bisection found that this patch > introduced a regression in next-20211019 with a NULL pointer > dereference, which only seems to be affecting QEMU but across all > architectures. > > More details about the regression can be found here: > > https://linux.kernelci.org/test/job/next/branch/master/kernel/next-20211019/plan/baseline/ > https://linux.kernelci.org/test/case/id/616ea20eb7104071c43358ea/ > > See also all the test jobs involved in the automated bisection: > > https://lava.collabora.co.uk/scheduler/device_type/qemu?dt_search=bisection-287 > > If you do send a fix, please include this trailer: > > Reported-by: "kernelci.org bot" <bot@xxxxxxxxxxxx> > > > Please let us know if this seems like a valid bisection result > and if you need any help to debug the issue or try a fix. This got fixed yesterday, current tree is fine. -- Jens Axboe
