Re: [RESEND PATCH 1/2] perf/x86/intel/uncore: Fix missing marker for snr_uncore_imc_freerunning_events

[Peter Zijlstra <peterz@infradead.org>]

On Thu, Jan 16, 2020 at 12:02:09PM -0800, kan.liang@linux.intel.com wrote:
> From: Kan Liang <kan.liang@linux.intel.com>
> 
> An Oops during the boot is found on some SNR machines.
> 
> [   15.795410] BUG: unable to handle page fault for address:
> 00000000000022b0
> [   15.795412] #PF: supervisor read access in kernel mode
> [   15.795413] #PF: error_code(0x0000) - not-present page
> [   15.795414] PGD 0 P4D 0
> [   15.795418] Oops: 0000 [#1] SMP NOPTI
> [   15.795420] CPU: 6 PID: 941 Comm: systemd-udevd Not tainted
> 5.3.0-snr-v5.3 #292
> [   15.795421] Hardware name: Intel Corporation JACOBSVILLE/JACOBSVILLE,
> BIOS JBVLCRB1.86B.0011.D44.1909191126 09/19/2019
> [   15.795428] RIP: 0010:strlen+0x0/0x20
> [   15.795431] Code: 48 89 f9 74 09 48 83 c1 01 80 39 00 75 f7 31 d2 44
> 0f
> b6 04 16 44 88 04 11 48 83 c2 01 45 84 c0 75 ee c3 0f 1f 80 00 00 00 00
> <80> 3f 00 74 10 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 c3 31
> [   15.855395] i801_smbus 0000:00:1f.4: SPD Write Disable is set
> [   15.858351] RSP: 0018:ffffaeb4812039c8 EFLAGS: 00010202
> [   15.858353] RAX: 0000000000000000 RBX: ffff9fec99c71300 RCX:
> 0000000000008000
> [   15.858354] RDX: 00000000000022b0 RSI: 0000000000000cc0 RDI:
> 00000000000022b0
> [   15.858355] RBP: 00000000000022b0 R08: 0000000000000000 R09:
> 0000000000000000
> [   15.858356] R10: 0000000000000000 R11: 0000000000000000 R12:
> ffff9fec8583a800
> [   15.858357] R13: 0000000000000cc0 R14: ffff9fec94015648 R15:
> ffff9fec81f291a8
> [   15.858358] FS:  00007f89e7160940(0000) GS:ffff9fec9dc00000(0000)
> knlGS:0000000000000000
> [   15.858361] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   15.864343] i801_smbus 0000:00:1f.4: SMBus using polling
> [   15.869998] CR2: 00000000000022b0 CR3: 0000000842ca2000 CR4:
> 0000000000340ee0
> [   15.870000] Call Trace:
> [   15.870006]  kstrdup+0x1a/0x60
> [   15.870012]  __kernfs_new_node+0x41/0x1f0
> [   15.870018]  ? __mutex_unlock_slowpath+0x4d/0x2a0
> [   15.895135] ioatdma 0000:00:01.3: enabling device (0004 -> 0006)
> [   15.899395]  kernfs_new_node+0x36/0x60
> [   15.899400]  __kernfs_create_file+0x2c/0xf3
> [   15.961374]  sysfs_add_file_mode_ns+0xa4/0x1a0
> [   15.961379]  internal_create_group+0x117/0x370
> [   15.972133]  ? sysfs_add_file_mode_ns+0xa4/0x1a0
> [   15.972138]  internal_create_groups.part.0+0x3d/0xa0
> [   15.982656]  device_add+0x625/0x690
> [   15.982662]  pmu_dev_alloc+0x93/0xf0
> [   15.982664]  perf_pmu_register+0x292/0x3e0
> [   15.982674]  uncore_pmu_register+0x76/0x120 [intel_uncore]
> [   15.982681]  intel_uncore_init+0x1fd/0xe2c [intel_uncore]
> [   15.982688]  ? uncore_types_init+0x1d4/0x1d4 [intel_uncore]
> [   16.013580]  do_one_initcall+0x5d/0x2e4
> [   16.013584]  ? do_init_module+0x23/0x230
> [   16.013586]  ? rcu_read_lock_sched_held+0x6b/0x80
> [   16.013589]  ? kmem_cache_alloc_trace+0x2c4/0x2f0
> [   16.013591]  ? do_init_module+0x23/0x230
> [   16.013594]  do_init_module+0x5c/0x230
> [   16.013597]  load_module+0x2779/0x2a90
> [   16.013605]  ? ima_post_read_file+0xfd/0x110
> [   16.026926] ioatdma 0000:00:01.4: enabling device (0004 -> 0006)
> [   16.028808]  ? __do_sys_finit_module+0xaa/0x110
> [   16.060527]  __do_sys_finit_module+0xaa/0x110
> [   16.060536]  do_syscall_64+0x5c/0xb0
> [   16.060540]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> 
> This snr_uncore_imc_freerunning_events array was missing an end-marker.

Surely you can convey the same without the need to include that splat?
That is, what actual useful information is there that you cannot more
easily write?