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a=Ol13hO9ccFRV9qXi2t6ftBPywas=:19 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=yJojWOMRYYMA:10 a=VwQbUJbxAAAA:8 a=p0WdMEafAAAA:8 a=NzbjGtntMflMrEhWyS0A:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1117,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-09-04_06,2025-09-04_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 priorityscore=1501 spamscore=0 adultscore=0 malwarescore=0 impostorscore=0 phishscore=0 bulkscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2507300000 definitions=firstrun Hi, I'd like to draw the attention of the scheduler maintainers to a number of kernel bugzilla reports submitted by a colleague a couple of weeks ago: 6.12.18: https://bugzilla.kernel.org/show_bug.cgi?id=220447 https://bugzilla.kernel.org/show_bug.cgi?id=220448 v6.16-rt3 https://bugzilla.kernel.org/show_bug.cgi?id=220450 https://bugzilla.kernel.org/show_bug.cgi?id=220449 There seems to be something wrong with either the logic or the locking. In one case this resulted in a NULL pointer dereference in pick_next_entity(). In another case it resulted in BUG_ON(!rq->nr_running) in dequeue_top_rt_rq() and SCHED_WARN_ON(!se->on_rq) in update_entity_lag(). My colleague suggests that the NULL pointer dereference may be due to pick_eevdf() returning NULL in pick_next_entity(). I did some digging and found that https://gitlab.com/linux-kernel/stable/-/commit/86b37810 would not have been included in 6.12.18, but the equivalent fix should have been in the 6.16 load. We haven't yet bottomed out the root cause. Any suggestions or assistance would be appreciated. Thanks, Chris