[Intel-gfx] [PATCH] drm/i915/perf: Initialise dynamic sysfs group before creation

[Lionel Landwerlin]

Right, that's exactly what I was asking in our previous exchange.

You need to leave the memset() I think, because we check further down 
that function that id == 0 to detect failure to recognize that the (Gen, 
GT) is supported.
Unless there is a guarantee that dev_priv is fully memset()?

Thanks a lot,

-
Lionel

On 09/08/17 15:47, Chris Wilson wrote:
> Another case where we need to call sysfs_attr_init() to setup the
> internal lockdep class prior to use:
>
> [    9.325229] BUG: key ffff880168bc7bb0 not in .data!
> [    9.325240] DEBUG_LOCKS_WARN_ON(1)
> [    9.325250] ------------[ cut here ]------------
> [    9.325280] WARNING: CPU: 1 PID: 275 at kernel/locking/lockdep.c:3156 lockdep_init_map+0x1b2/0x1c0
> [    9.325301] Modules linked in: intel_powerclamp(+) coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel i915(+) snd_hda_intel snd_hda_codec snd_hwdep r8169 mii snd_hda_core snd_pcm prime_numbers i2c_hid pinctrl_geminilake pinctrl_intel
> [    9.325375] CPU: 1 PID: 275 Comm: modprobe Not tainted 4.13.0-rc4-CI-Trybot_1040+ #1
> [    9.325395] Hardware name: Intel Corp. Geminilake/GLK RVP2 LP4SD (07), BIOS GELKRVPA.X64.0045.B51.1704281422 04/28/2017
> [    9.325422] task: ffff8801721a4ec0 task.stack: ffffc900001dc000
> [    9.325440] RIP: 0010:lockdep_init_map+0x1b2/0x1c0
> [    9.325456] RSP: 0018:ffffc900001dfa10 EFLAGS: 00010282
> [    9.325473] RAX: 0000000000000016 RBX: ffff880168d54b80 RCX: 0000000000000000
> [    9.325488] RDX: 0000000080000001 RSI: 0000000000000001 RDI: ffffffff810f0800
> [    9.325505] RBP: ffffc900001dfa30 R08: 0000000000000001 R09: 0000000000000000
> [    9.325521] R10: 0000000000000000 R11: 0000000000000000 R12: ffff880168bc7bb0
> [    9.325537] R13: 0000000000000000 R14: ffff880168bc7b98 R15: ffffffff81a263a0
> [    9.325554] FS:  00007fb60c3fd700(0000) GS:ffff88017fc80000(0000) knlGS:0000000000000000
> [    9.325574] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [    9.325588] CR2: 0000006582777d80 CR3: 000000016d818000 CR4: 00000000003406e0
> [    9.325604] Call Trace:
> [    9.325618]  __kernfs_create_file+0x76/0xe0
> [    9.325632]  sysfs_add_file_mode_ns+0x8a/0x1a0
> [    9.325646]  internal_create_group+0xea/0x2c0
> [    9.325660]  sysfs_create_group+0x13/0x20
> [    9.325737]  i915_perf_register+0xde/0x220 [i915]
> [    9.325800]  i915_driver_load+0xa77/0x16c0 [i915]
> [    9.325863]  i915_pci_probe+0x37/0x90 [i915]
> [    9.325880]  pci_device_probe+0xa8/0x130
> [    9.325894]  driver_probe_device+0x29c/0x450
> [    9.325908]  __driver_attach+0xe3/0xf0
> [    9.325922]  ? driver_probe_device+0x450/0x450
> [    9.325935]  bus_for_each_dev+0x62/0xa0
> [    9.325948]  driver_attach+0x1e/0x20
> [    9.325960]  bus_add_driver+0x173/0x270
> [    9.325974]  driver_register+0x60/0xe0
> [    9.325986]  __pci_register_driver+0x60/0x70
> [    9.326044]  i915_init+0x6f/0x78 [i915]
> [    9.326066]  ? 0xffffffffa024e000
> [    9.326079]  do_one_initcall+0x43/0x170
> [    9.326094]  ? rcu_read_lock_sched_held+0x7a/0x90
> [    9.326109]  ? kmem_cache_alloc_trace+0x261/0x2d0
> [    9.326124]  do_init_module+0x5f/0x206
> [    9.326137]  load_module+0x2561/0x2da0
> [    9.326150]  ? show_coresize+0x30/0x30
> [    9.326165]  ? kernel_read_file+0x105/0x190
> [    9.326180]  SyS_finit_module+0xc1/0x100
> [    9.326192]  ? SyS_finit_module+0xc1/0x100
> [    9.326210]  entry_SYSCALL_64_fastpath+0x1c/0xb1
> [    9.326223] RIP: 0033:0x7fb60bf359f9
> [    9.326234] RSP: 002b:00007fff92b47c48 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
> [    9.326255] RAX: ffffffffffffffda RBX: ffffffff814898a3 RCX: 00007fb60bf359f9
> [    9.326271] RDX: 0000000000000000 RSI: 00000028a9ceef8b RDI: 0000000000000000
> [    9.326287] RBP: ffffc900001dff88 R08: 0000000000000000 R09: 0000000000000000
> [    9.326303] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000040000
> [    9.326319] R13: 00000028aaef2a70 R14: 0000000000000000 R15: 00000028aaeee5d0
> [    9.326339]  ? __this_cpu_preempt_check+0x13/0x20
> [    9.326353] Code: f1 39 00 85 c0 0f 84 38 ff ff ff 83 3d 9f 44 ce 01 00 0f 85 2b ff ff ff 48 c7 c6 b2 a2 c7 81 48 c7 c7 53 40 c5 81 e8 3f 82 01 00 <0f> ff e9 11 ff ff ff 0f 1f 80 00 00 00 00 55 31 c9 31 d2 31 f6
>
> Fixes: 701f8231a2fe ("drm/i915/perf: prune OA configs")
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> Cc: Matthew Auld <matthew.auld at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_perf.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> index e3e2663117e9..1be355d14e8a 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -2908,8 +2908,7 @@ void i915_perf_register(struct drm_i915_private *dev_priv)
>   	if (!dev_priv->perf.metrics_kobj)
>   		goto exit;
>   
> -	memset(&dev_priv->perf.oa.test_config, 0,
> -	       sizeof(dev_priv->perf.oa.test_config));
> +	sysfs_attr_init(&dev_priv->perf.oa.test_config.sysfs_metric_id.attr);
>   
>   	if (IS_HASWELL(dev_priv)) {
>   		i915_perf_load_test_config_hsw(dev_priv);