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b=Zhh25imj3X7IruBss1+Hb2fGZ3AdiB10qTZ1qOoLKmN0GLuFnQmVcQt6AIhFqC5b pALUL+q/06jLZy1zf6WMcRoL9hbPuC4R2m803mP1QynCxYrO6YwBpVqYOl1dDXap0 z60xP1ctIVDrpBL7DxGK/RNKpFmQ7KpJNYvHc31WQhuNA+xrI0ClI+JzdI74goVK5 mo4+COmt+52CPQBHwlX9ae4YwIb5GdrVPeER6aehjvfMU+1LMjyD/VVGzLV/0aY4S J1VssSiKSWcuvLKbOILNjknVVEVchKCTyyfzxLwcOLu4cVR4RLN7dXfXowI2LxCrA hz2BYZK9IiLBg7ooow== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from homer.fritz.box ([91.212.106.56]) by mail.gmx.net (mrgmx005 [212.227.17.190]) with ESMTPSA (Nemesis) id 1MaJ3n-1sUbFm41Mz-00PLir; Fri, 20 Sep 2024 04:15:32 +0200 Message-ID: <177646b0c427786c90a8ccb67f5b956a12759d3a.camel@gmx.de> Subject: Re: [patch] Re: [PowerPC][Linux-next][6.11.0-rc4-next-20240820] OOPs while running LTP FS Stress From: Mike Galbraith To: Venkat Rao Bagalkote , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, peterz@infradead.org, vschneid@redhat.com, mingo@kernel.org, sfr@canb.auug.org.au Date: Fri, 20 Sep 2024 04:15:30 +0200 In-Reply-To: References: <82b9c434-a0fd-4488-95be-a45b8cd4b6e6@linux.vnet.ibm.com> <2fb24ab402d9de45e3cf16e6ba0ad23a7843e5c1.camel@gmx.de> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.42.4 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Post: List-Subscribe: , , List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:dsBviHucoPVCIAkRArCXYTRRur6moHQ5PlWxYDaBZ/fY83nVrrz PpGRUkO2aYEq04jy2P6KV61taffA/FL1dP3Ddl/QYoQQygpZWYXqEjX19bZIlBl9H0vI8Fr Bb3X1azisbO0yzKFabdrMc6m9Na0+qdgsngTYcd45yZLLUg+dJMYhdnHSlEvgHTBKam33VV 0z5mri6YzM0GfjmCJppBQ== UI-OutboundReport: notjunk:1;M01:P0:Z7LK3j1vvi8=;vhpgIoYqbeOwMza2brpmCQ8gfnf dqJeSnSP04ZTvJo5mvCLOso3qVQiLsq5vIH4/NLv2hNejkPhSSJRcktTvDCuuyGIqoxVA5NZE w5I4p3o7Djq/sa1sL6BmxDPTXF2UC1aqQHBUv/3ax5xVRHT7UZmhxsFHmm01geycAzVTrsQE7 ccMCRTMkbkApeIL+gzypmI5vDtZdQDqR4xnbZ3mmd5frOgFHIWA/owP9vvvbsasI2Zg0krTS7 OZOXqk7pr6nAFbx23/RCfSTXsaF18McgOMvr9cNXC+Gv3Hr9nLSg2mYikRr+T1hfxmtrSZM7S TMystNrk0XOll71WcGmquY8ClFWcPZgrkteBrI0ljUaFZ8cn0xLbdU49+efWRF3JRRALgYOoO vBWtqmExAK7SHyXJAbhtOJfvAN9FncG6IHeJjI0BriA6zLvq9DvLV2U7J0snVj/wN/M5vmNPQ UnL1nILRXtlkA/3fJx9JWOs0c0O3MS9rBs/AHINVG8inI+WPM4JpMhtVIUMxbPai0YdwnWfpM bHUYvM7go1jPC1Y/UQjQKxKN0Jfg3CvaaKjPUvlBRRrTzyVZLVzeoK5yD0MfBhegHDQWxcaPk mmV4bOh4tDryktKaYeGY9iWdOOt56Z0LWdyY1k5Dp15ANcZ5jYFwyeEdn56zIUin15qTW+ceu Z3V9XZkbrH4CxYV03/8gXtUsw6uKDYydB3+ABnRMLwv714A7nV0KZJkUcrfU0Kep/i5SyVsYx jrS1VzB0foJAqr8vvsE7n1T/skQvtqnnSUHxXc/aK9Mu7ImirFMGjlcHvApXWiOQzADosAQ1V DJEykGUMtD0tljTHZRgjfELg== On Thu, 2024-09-19 at 20:09 +0530, Venkat Rao Bagalkote wrote: > > Please add the below tags. > > > Reported-by: Venkat Rao Bagalkote > > Tested-by: Venkat Rao Bagalkote Sure, and while at it I can brush patchlet's rather scruffy fur. 1. on_rq being implied by sched_delayed, redundant check can go. 2. no tasks anywhere in sight, DEQUEUE_SPECIAL can go. 3. use of unlikely in an unlikely path can also go. No functional change. Too bad everything around there fits in 80 characters, or a couple useless diffstat plus signs could go too. sched: Fix sched_delayed vs cfs_bandwidth Meeting an unfinished DELAY_DEQUEUE treated entity in unthrottle_cfs_rq() leads to a couple terminal scenarios. Finish it first, so ENQUEUE_WAKEUP can proceed as it would have sans DELAY_DEQUEUE treatment. Fixes: 152e11f6df29 ("sched/fair: Implement delayed dequeue") Reported-by: Venkat Rao Bagalkote Tested-by: Venkat Rao Bagalkote Signed-off-by: Mike Galbraith =2D-- kernel/sched/fair.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) =2D-- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6049,10 +6049,13 @@ void unthrottle_cfs_rq(struct cfs_rq *cf for_each_sched_entity(se) { struct cfs_rq *qcfs_rq =3D cfs_rq_of(se); - if (se->on_rq) { - SCHED_WARN_ON(se->sched_delayed); + /* Handle any unfinished DELAY_DEQUEUE business first. */ + if (se->sched_delayed) { + int flags =3D DEQUEUE_SLEEP | DEQUEUE_DELAYED; + + dequeue_entity(qcfs_rq, se, flags); + } else if (se->on_rq) break; - } enqueue_entity(qcfs_rq, se, ENQUEUE_WAKEUP); if (cfs_rq_is_idle(group_cfs_rq(se)))