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McKenney" , "Gautham R. Shenoy" , Florian Weimer , Tim Chen , Yury Norov Subject: Re: [patch V3 00/20] sched: Rewrite MM CID management In-Reply-To: References: <20251029123717.886619142@linutronix.de> <47e73026-390e-40d6-a860-10e9378a3bf3@linux.ibm.com> Date: Fri, 31 Oct 2025 20:36:06 +0100 Message-ID: <87ecqisw2h.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Thu, Oct 30 2025 at 12:10, Shrikanth Hegde wrote: >> I am running into crash at boot on power10 pseries. >> Thought of putting it here first. Me trying to figure out why. >>=20 >> I am using your tree. >> git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git Can you update and revalidate? There are a couple of fixes there though I don't know how they would be related. >> Oops: Kernel access of bad area, sig: 7 [#3] >> LE PAGE_SIZE=3D64K MMU=3DRadix=C2=A0 SMP NR_CPUS=3D8192 NUMA pSeries >> Modules linked in: drm drm_panel_orientation_quirks xfs sd_mod sg=20 >> ibmvscsi ibmveth scsi_transport_srp pseries_wdt dm_mirror dm_region_hash= =20 >> dm_log dm_mod fuse >> CPU: 96 UID: 0 PID: 0 Comm: swapper/96 Tainted: G=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0 D W=20=20=20=20=20=20=20=20=20=20=20 >> 6.18.0-rc3+ #4 PREEMPT(lazy) >> Tainted: [D]=3DDIE, [W]=3DWARN >> NIP [c0000000001b5c10] mm_cid_switch_to+0x58/0x52c If it happens again, can you decode the source line? >> LR [c000000001117c84] __schedule+0x4bc/0x760 >> Call Trace: >> [c00000668367fde0] [c0000000001b53c8] __pick_next_task+0x60/0x2ac=20 >> (unreliable) >> [c00000668367fe40] [c000000001117a14] __schedule+0x24c/0x760 >> [c00000668367fee0] [c0000000011183d0] schedule_idle+0x3c/0x64 >> [c00000668367ff10] [c0000000001f2470] do_idle+0x15c/0x1ac >> [c00000668367ff60] [c0000000001f2788] cpu_startup_entry+0x4c/0x50 >> [c00000668367ff90] [c00000000005ef20] start_secondary+0x284/0x288 >> [c00000668367ffe0] [c00000000000e158] start_secondary_prolog+0x10/0x14 >>=20 > > Issue happens with NR_CPUS=3D8192. System boots fine with NR_CPUS=3D2048 Hmm. Let me build a kernel with 8K and throw it at a VM then. Thanks, tglx