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[66.187.233.206]) by smtp.gmail.com with ESMTPSA id 16sm126561qkl.100.2019.06.27.14.21.13 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 Jun 2019 14:21:13 -0700 (PDT) Message-ID: <1561670472.5154.98.camel@lca.pw> Subject: power9 NUMA crash while reading debugfs imc_cmd From: Qian Cai To: "Aneesh Kumar K.V" , Michael Ellerman , Anju T Sudhakar Date: Thu, 27 Jun 2019 17:21:12 -0400 Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6 (3.22.6-10.el7) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit 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: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Read of debugfs imc_cmd file for a memory-less node will trigger a crash below on this power9 machine which has the following NUMA layout. I don't understand why I only saw it recently on linux-next where it was tested everyday. I can reproduce it back to 4.20 where 4.18 seems work fine. # cat /sys/kernel/debug/powerpc/imc/imc_cmd_252 (On a 4.18-based kernel) 0x0000000000000000 # numactl -H available: 6 nodes (0,8,252-255) node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 node 0 size: 130210 MB node 0 free: 128406 MB node 8 cpus: 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 node 8 size: 130784 MB node 8 free: 130051 MB node 252 cpus: node 252 size: 0 MB node 252 free: 0 MB node 253 cpus: node 253 size: 0 MB node 253 free: 0 MB node 254 cpus: node 254 size: 0 MB node 254 free: 0 MB node 255 cpus: node 255 size: 0 MB node 255 free: 0 MB node distances: node 0 8 252 253 254 255 0: 10 40 80 80 80 80 8: 40 10 80 80 80 80 252: 80 80 10 80 80 80 253: 80 80 80 10 80 80 254: 80 80 80 80 10 80 255: 80 80 80 80 80 10 # cat /sys/kernel/debug/powerpc/imc/imc_cmd_252 [ 1139.415461][ T5301] Faulting instruction address: 0xc0000000000d0d58 [ 1139.415492][ T5301] Oops: Kernel access of bad area, sig: 11 [#1] [ 1139.415509][ T5301] LE PAGE_SIZE=64K MMU=Radix MMU=Hash SMP NR_CPUS=256 DEBUG_PAGEALLOC NUMA PowerNV [ 1139.415542][ T5301] Modules linked in: i2c_opal i2c_core ip_tables x_tables xfs sd_mod bnx2x mdio ahci libahci tg3 libphy libata firmware_class dm_mirror dm_region_hash dm_log dm_mod [ 1139.415595][ T5301] CPU: 67 PID: 5301 Comm: cat Not tainted 5.2.0-rc6-next- 20190627+ #19 [ 1139.415634][ T5301] NIP: c0000000000d0d58 LR: c00000000049aa18 CTR: c0000000000d0d50 [ 1139.415675][ T5301] REGS: c00020194548f9e0 TRAP: 0300 Not tainted (5.2.0- rc6-next-20190627+) [ 1139.415705][ T5301] MSR: 9000000000009033 CR: 28022822 XER: 00000000 [ 1139.415777][ T5301] CFAR: c00000000049aa14 DAR: 000000000003fc08 DSISR: 40000000 IRQMASK: 0 [ 1139.415777][ T5301] GPR00: c00000000049aa18 c00020194548fc70 c0000000016f8b00 000000000003fc08 [ 1139.415777][ T5301] GPR04: c00020194548fcd0 0000000000000000 0000000014884e73 ffffffff00011eaa [ 1139.415777][ T5301] GPR08: 000000007eea5a52 c0000000000d0d50 0000000000000000 0000000000000000 [ 1139.415777][ T5301] GPR12: c0000000000d0d50 c000201fff7f8c00 0000000000000000 0000000000000000 [ 1139.415777][ T5301] GPR16: 000000000000000d 00007fffeb0c3368 ffffffffffffffff 0000000000000000 [ 1139.415777][ T5301] GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000020000 [ 1139.415777][ T5301] GPR24: 0000000000000000 0000000000000000 0000000000020000 000000010ec90000 [ 1139.415777][ T5301] GPR28: c00020194548fdf0 c00020049a584ef8 0000000000000000 c00020049a584ea8 [ 1139.416116][ T5301] NIP [c0000000000d0d58] imc_mem_get+0x8/0x20 [ 1139.416143][ T5301] LR [c00000000049aa18] simple_attr_read+0x118/0x170 [ 1139.416158][ T5301] Call Trace: [ 1139.416182][ T5301] [c00020194548fc70] [c00000000049a970] simple_attr_read+0x70/0x170 (unreliable) [ 1139.416255][ T5301] [c00020194548fd10] [c00000000054385c] debugfs_attr_read+0x6c/0xb0 [ 1139.416305][ T5301] [c00020194548fd60] [c000000000454c1c] __vfs_read+0x3c/0x70 [ 1139.416363][ T5301] [c00020194548fd80] [c000000000454d0c] vfs_read+0xbc/0x1a0 [ 1139.416392][ T5301] [c00020194548fdd0] [c00000000045519c] ksys_read+0x7c/0x140 [ 1139.416434][ T5301] [c00020194548fe20] [c00000000000b108] system_call+0x5c/0x70 [ 1139.416473][ T5301] Instruction dump: [ 1139.416511][ T5301] 4e800020 60000000 7c0802a6 60000000 7c801d28 38600000 4e800020 60000000 [ 1139.416572][ T5301] 60000000 60000000 7c0802a6 60000000 <7d201c28> 38600000 f9240000 4e800020 [ 1139.416636][ T5301] ---[ end trace c44d1fb4ace04784 ]--- [ 1139.520686][ T5301] [ 1140.520820][ T5301] Kernel panic - not syncing: Fatal exception