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<9D4A658A-5F77-4C33-904A-126E6052B205@linux.vnet.ibm.com> In-Reply-To: <9D4A658A-5F77-4C33-904A-126E6052B205@linux.vnet.ibm.com> From: Odin Ugedal Date: Mon, 21 Jun 2021 11:39:08 +0200 Message-ID: Subject: Re: [powerpc][5.13.0-rc7] Kernel warning (kernel/sched/fair.c:401) while running LTP tests To: Sachin Sant Cc: open list , linuxppc-dev@lists.ozlabs.org, Odin Ugedal , Peter Zijlstra , Vincent Guittot Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org man. 21. jun. 2021 kl. 08:33 skrev Sachin Sant = : > > While running LTP tests (cfs_bandwidth01) against 5.13.0-rc7 kernel on a = powerpc box > following warning is seen > > [ 6611.331827] ------------[ cut here ]------------ > [ 6611.331855] rq->tmp_alone_branch !=3D &rq->leaf_cfs_rq_list > [ 6611.331862] WARNING: CPU: 8 PID: 0 at kernel/sched/fair.c:401 unthrott= le_cfs_rq+0x4cc/0x590 > [ 6611.331883] Modules linked in: nfsv3 nfs_acl nfs lockd grace fscache n= etfs tun brd overlay vfat fat btrfs blake2b_generic xor zstd_compress raid6= _pq xfs loop sctp ip6_udp_tunnel udp_tunnel libcrc32c dm_mod bonding rfkill= sunrpc pseries_rng xts vmx_crypto sch_fq_codel ip_tables ext4 mbcache jbd2= sd_mod t10_pi sg ibmvscsi ibmveth scsi_transport_srp fuse [last unloaded: = init_module] > [ 6611.331957] CPU: 8 PID: 0 Comm: swapper/8 Tainted: G OE = 5.13.0-rc6-gcba5e97280f5 #1 > [ 6611.331968] NIP: c0000000001b7aac LR: c0000000001b7aa8 CTR: c00000000= 0722d30 > [ 6611.331976] REGS: c00000000274f3a0 TRAP: 0700 Tainted: G O= E (5.13.0-rc6-gcba5e97280f5) > [ 6611.331985] MSR: 8000000000029033 CR: 4800022= 4 XER: 00000005 > [ 6611.332002] CFAR: c00000000014ca20 IRQMASK: 1 > [ 6611.332002] GPR00: c0000000001b7aa8 c00000000274f640 c000000001abaf00 = 000000000000002d > [ 6611.332002] GPR04: 00000000ffff7fff c00000000274f300 0000000000000027 = c000000efdb07e08 > [ 6611.332002] GPR08: 0000000000000023 0000000000000001 0000000000000027 = c000000001976680 > [ 6611.332002] GPR12: 0000000000000000 c000000effc0be80 c000000ef07b3f90 = 000000001eefe200 > [ 6611.332002] GPR16: 0000000000000000 0000000000000000 0000000000000000 = 0000000000000000 > [ 6611.332002] GPR20: 0000000000000001 c000000000fa6c08 c000000000fa6030 = 0000000000000001 > [ 6611.332002] GPR24: 0000000000000000 0000000000000000 c000000efde12380 = 0000000000000001 > [ 6611.332002] GPR28: 0000000000000001 0000000000000000 c000000efde12400 = 0000000000000000 > [ 6611.332094] NIP [c0000000001b7aac] unthrottle_cfs_rq+0x4cc/0x590 > [ 6611.332104] LR [c0000000001b7aa8] unthrottle_cfs_rq+0x4c8/0x590 > [ 6611.332113] Call Trace: > [ 6611.332116] [c00000000274f640] [c0000000001b7aa8] unthrottle_cfs_rq+0x= 4c8/0x590 (unreliable) > [ 6611.332128] [c00000000274f6e0] [c0000000001b7e38] distribute_cfs_runti= me+0x1d8/0x280 > [ 6611.332139] [c00000000274f7b0] [c0000000001b81d0] sched_cfs_period_tim= er+0x140/0x330 > [ 6611.332149] [c00000000274f870] [c00000000022a03c] __hrtimer_run_queues= +0x17c/0x380 > [ 6611.332158] [c00000000274f8f0] [c00000000022ac68] hrtimer_interrupt+0x= 128/0x2f0 > [ 6611.332168] [c00000000274f9a0] [c00000000002940c] timer_interrupt+0x13= c/0x370 > [ 6611.332179] [c00000000274fa00] [c000000000009c04] decrementer_common_v= irt+0x1a4/0x1b0 > [ 6611.332189] --- interrupt: 900 at plpar_hcall_norets_notrace+0x18/0x24 > [ 6611.332199] NIP: c0000000000f6af8 LR: c000000000a05f68 CTR: 000000000= 0000000 > [ 6611.332206] REGS: c00000000274fa70 TRAP: 0900 Tainted: G O= E (5.13.0-rc6-gcba5e97280f5) > [ 6611.332214] MSR: 800000000280b033 = CR: 28000224 XER: 00000000 > [ 6611.332234] CFAR: 0000000000000c00 IRQMASK: 0 > [ 6611.332234] GPR00: 0000000000000000 c00000000274fd10 c000000001abaf00 = 0000000000000000 > [ 6611.332234] GPR04: 00000000000000c0 0000000000000080 0001a91c68b80fa1 = 00000000000003dc > [ 6611.332234] GPR08: 000000000001f400 0000000000000001 0000000000000000 = 0000000000000000 > [ 6611.332234] GPR12: 0000000000000000 c000000effc0be80 c000000ef07b3f90 = 000000001eefe200 > [ 6611.332234] GPR16: 0000000000000000 0000000000000000 0000000000000000 = 0000000000000000 > [ 6611.332234] GPR20: 0000000000000001 0000000000000002 0000000000000010 = c0000000019fe2f8 > [ 6611.332234] GPR24: 0000000000000001 00000603517d757e 0000000000000000 = 0000000000000000 > [ 6611.332234] GPR28: 0000000000000001 0000000000000000 c000000001231f90 = c000000001231f98 > [ 6611.332323] NIP [c0000000000f6af8] plpar_hcall_norets_notrace+0x18/0x2= 4 > [ 6611.332332] LR [c000000000a05f68] check_and_cede_processor+0x48/0x60 > [ 6611.332340] --- interrupt: 900 > [ 6611.332345] [c00000000274fd10] [c000000efdb92380] 0xc000000efdb92380 (= unreliable) > [ 6611.332355] [c00000000274fd70] [c000000000a063bc] dedicated_cede_loop+= 0x9c/0x1b0 > [ 6611.332364] [c00000000274fdc0] [c000000000a02b04] cpuidle_enter_state+= 0x2e4/0x4e0 > [ 6611.332375] [c00000000274fe20] [c000000000a02da0] cpuidle_enter+0x50/0= x70 > [ 6611.332385] [c00000000274fe60] [c0000000001a883c] call_cpuidle+0x4c/0x= 80 > [ 6611.332393] [c00000000274fe80] [c0000000001a8ee0] do_idle+0x380/0x3e0 > [ 6611.332402] [c00000000274ff00] [c0000000001a91bc] cpu_startup_entry+0x= 3c/0x40 > [ 6611.332411] [c00000000274ff30] [c000000000063ff8] start_secondary+0x29= 8/0x2b0 > [ 6611.332421] [c00000000274ff90] [c00000000000c754] start_secondary_prol= og+0x10/0x14 > [ 6611.332430] Instruction dump: > [ 6611.332435] 4bfffc44 3d22fff6 8929f328 2f890000 409efea4 39200001 3d42= fff6 3c62ff4f > [ 6611.332451] 3863bcd8 992af328 4bf94f15 60000000 <0fe00000> 4bfffe80 7f= 6407b4 7f43d378 > [ 6611.332466] ---[ end trace 1346f865cd1cae91 ]=E2=80=94 > > 5.13.0-rc6 was good. Bisect points to following patch > > commit a7b359fc6a37 > sched/fair: Correctly insert cfs_rq's to list on unthrottle > > The test runs to completion(without this warning) if the patch is reverte= d. > > Thanks > -Sachin > Hi, Thanks for the report! I have a theory about what is possibly causing this, so I will try to reproduce it and see if my assumptions are correct. 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<9D4A658A-5F77-4C33-904A-126E6052B205@linux.vnet.ibm.com> In-Reply-To: <9D4A658A-5F77-4C33-904A-126E6052B205@linux.vnet.ibm.com> From: Odin Ugedal Date: Mon, 21 Jun 2021 11:39:08 +0200 Message-ID: Subject: Re: [powerpc][5.13.0-rc7] Kernel warning (kernel/sched/fair.c:401) while running LTP tests To: Sachin Sant Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Mailman-Approved-At: Mon, 21 Jun 2021 20:44:21 +1000 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Zijlstra , Odin Ugedal , linuxppc-dev@lists.ozlabs.org, open list , Vincent Guittot Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" man. 21. jun. 2021 kl. 08:33 skrev Sachin Sant = : > > While running LTP tests (cfs_bandwidth01) against 5.13.0-rc7 kernel on a = powerpc box > following warning is seen > > [ 6611.331827] ------------[ cut here ]------------ > [ 6611.331855] rq->tmp_alone_branch !=3D &rq->leaf_cfs_rq_list > [ 6611.331862] WARNING: CPU: 8 PID: 0 at kernel/sched/fair.c:401 unthrott= le_cfs_rq+0x4cc/0x590 > [ 6611.331883] Modules linked in: nfsv3 nfs_acl nfs lockd grace fscache n= etfs tun brd overlay vfat fat btrfs blake2b_generic xor zstd_compress raid6= _pq xfs loop sctp ip6_udp_tunnel udp_tunnel libcrc32c dm_mod bonding rfkill= sunrpc pseries_rng xts vmx_crypto sch_fq_codel ip_tables ext4 mbcache jbd2= sd_mod t10_pi sg ibmvscsi ibmveth scsi_transport_srp fuse [last unloaded: = init_module] > [ 6611.331957] CPU: 8 PID: 0 Comm: swapper/8 Tainted: G OE = 5.13.0-rc6-gcba5e97280f5 #1 > [ 6611.331968] NIP: c0000000001b7aac LR: c0000000001b7aa8 CTR: c00000000= 0722d30 > [ 6611.331976] REGS: c00000000274f3a0 TRAP: 0700 Tainted: G O= E (5.13.0-rc6-gcba5e97280f5) > [ 6611.331985] MSR: 8000000000029033 CR: 4800022= 4 XER: 00000005 > [ 6611.332002] CFAR: c00000000014ca20 IRQMASK: 1 > [ 6611.332002] GPR00: c0000000001b7aa8 c00000000274f640 c000000001abaf00 = 000000000000002d > [ 6611.332002] GPR04: 00000000ffff7fff c00000000274f300 0000000000000027 = c000000efdb07e08 > [ 6611.332002] GPR08: 0000000000000023 0000000000000001 0000000000000027 = c000000001976680 > [ 6611.332002] GPR12: 0000000000000000 c000000effc0be80 c000000ef07b3f90 = 000000001eefe200 > [ 6611.332002] GPR16: 0000000000000000 0000000000000000 0000000000000000 = 0000000000000000 > [ 6611.332002] GPR20: 0000000000000001 c000000000fa6c08 c000000000fa6030 = 0000000000000001 > [ 6611.332002] GPR24: 0000000000000000 0000000000000000 c000000efde12380 = 0000000000000001 > [ 6611.332002] GPR28: 0000000000000001 0000000000000000 c000000efde12400 = 0000000000000000 > [ 6611.332094] NIP [c0000000001b7aac] unthrottle_cfs_rq+0x4cc/0x590 > [ 6611.332104] LR [c0000000001b7aa8] unthrottle_cfs_rq+0x4c8/0x590 > [ 6611.332113] Call Trace: > [ 6611.332116] [c00000000274f640] [c0000000001b7aa8] unthrottle_cfs_rq+0x= 4c8/0x590 (unreliable) > [ 6611.332128] [c00000000274f6e0] [c0000000001b7e38] distribute_cfs_runti= me+0x1d8/0x280 > [ 6611.332139] [c00000000274f7b0] [c0000000001b81d0] sched_cfs_period_tim= er+0x140/0x330 > [ 6611.332149] [c00000000274f870] [c00000000022a03c] __hrtimer_run_queues= +0x17c/0x380 > [ 6611.332158] [c00000000274f8f0] [c00000000022ac68] hrtimer_interrupt+0x= 128/0x2f0 > [ 6611.332168] [c00000000274f9a0] [c00000000002940c] timer_interrupt+0x13= c/0x370 > [ 6611.332179] [c00000000274fa00] [c000000000009c04] decrementer_common_v= irt+0x1a4/0x1b0 > [ 6611.332189] --- interrupt: 900 at plpar_hcall_norets_notrace+0x18/0x24 > [ 6611.332199] NIP: c0000000000f6af8 LR: c000000000a05f68 CTR: 000000000= 0000000 > [ 6611.332206] REGS: c00000000274fa70 TRAP: 0900 Tainted: G O= E (5.13.0-rc6-gcba5e97280f5) > [ 6611.332214] MSR: 800000000280b033 = CR: 28000224 XER: 00000000 > [ 6611.332234] CFAR: 0000000000000c00 IRQMASK: 0 > [ 6611.332234] GPR00: 0000000000000000 c00000000274fd10 c000000001abaf00 = 0000000000000000 > [ 6611.332234] GPR04: 00000000000000c0 0000000000000080 0001a91c68b80fa1 = 00000000000003dc > [ 6611.332234] GPR08: 000000000001f400 0000000000000001 0000000000000000 = 0000000000000000 > [ 6611.332234] GPR12: 0000000000000000 c000000effc0be80 c000000ef07b3f90 = 000000001eefe200 > [ 6611.332234] GPR16: 0000000000000000 0000000000000000 0000000000000000 = 0000000000000000 > [ 6611.332234] GPR20: 0000000000000001 0000000000000002 0000000000000010 = c0000000019fe2f8 > [ 6611.332234] GPR24: 0000000000000001 00000603517d757e 0000000000000000 = 0000000000000000 > [ 6611.332234] GPR28: 0000000000000001 0000000000000000 c000000001231f90 = c000000001231f98 > [ 6611.332323] NIP [c0000000000f6af8] plpar_hcall_norets_notrace+0x18/0x2= 4 > [ 6611.332332] LR [c000000000a05f68] check_and_cede_processor+0x48/0x60 > [ 6611.332340] --- interrupt: 900 > [ 6611.332345] [c00000000274fd10] [c000000efdb92380] 0xc000000efdb92380 (= unreliable) > [ 6611.332355] [c00000000274fd70] [c000000000a063bc] dedicated_cede_loop+= 0x9c/0x1b0 > [ 6611.332364] [c00000000274fdc0] [c000000000a02b04] cpuidle_enter_state+= 0x2e4/0x4e0 > [ 6611.332375] [c00000000274fe20] [c000000000a02da0] cpuidle_enter+0x50/0= x70 > [ 6611.332385] [c00000000274fe60] [c0000000001a883c] call_cpuidle+0x4c/0x= 80 > [ 6611.332393] [c00000000274fe80] [c0000000001a8ee0] do_idle+0x380/0x3e0 > [ 6611.332402] [c00000000274ff00] [c0000000001a91bc] cpu_startup_entry+0x= 3c/0x40 > [ 6611.332411] [c00000000274ff30] [c000000000063ff8] start_secondary+0x29= 8/0x2b0 > [ 6611.332421] [c00000000274ff90] [c00000000000c754] start_secondary_prol= og+0x10/0x14 > [ 6611.332430] Instruction dump: > [ 6611.332435] 4bfffc44 3d22fff6 8929f328 2f890000 409efea4 39200001 3d42= fff6 3c62ff4f > [ 6611.332451] 3863bcd8 992af328 4bf94f15 60000000 <0fe00000> 4bfffe80 7f= 6407b4 7f43d378 > [ 6611.332466] ---[ end trace 1346f865cd1cae91 ]=E2=80=94 > > 5.13.0-rc6 was good. Bisect points to following patch > > commit a7b359fc6a37 > sched/fair: Correctly insert cfs_rq's to list on unthrottle > > The test runs to completion(without this warning) if the patch is reverte= d. > > Thanks > -Sachin > Hi, Thanks for the report! I have a theory about what is possibly causing this, so I will try to reproduce it and see if my assumptions are correct. Odin