Re: [PATCH v3] drm: Check output polling initialized before disabling

[Shradha Gupta]

Hi all, 
to me it seems like the patch has uncovered a genuine warning in drm_helper_probe_single_connector_modes() function.
Before calling drm_kms_helper_poll_enable() there should be check to see if mode_config.poll_enabled is set similar
to the new suspend/resume changes in the patch.
Is this understanding correct? Thoughts?

On Fri, Jan 19, 2024 at 02:46:47PM +0800, kernel test robot wrote:
> 
> 
> Hello,
> 
> kernel test robot noticed "WARNING:at_drivers/gpu/drm/drm_probe_helper.c:#drm_kms_helper_poll_enable[drm_kms_helper]" on:
> 
> commit: 98a690eb11a5f722cfff1dd5c3ac46f9ba326919 ("[PATCH v3] drm: Check output polling initialized before disabling")
> url: https://github.com/intel-lab-lkp/linux/commits/Shradha-Gupta/drm-Check-output-polling-initialized-before-disabling/20240115-124300
> base: git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
> patch subject: [PATCH v3] drm: Check output polling initialized before disabling
> 
> in testcase: boot
> 
> compiler: gcc-12
> test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
> 
> (please refer to attached dmesg/kmsg for entire log/backtrace)
> 
> 
> +-------------------------------------------------------------------------------------------+------------+------------+
> |                                                                                           | 45017df303 | 98a690eb11 |
> +-------------------------------------------------------------------------------------------+------------+------------+
> | WARNING:at_drivers/gpu/drm/drm_probe_helper.c:#drm_kms_helper_poll_enable[drm_kms_helper] | 0          | 8          |
> | RIP:drm_kms_helper_poll_enable[drm_kms_helper]                                            | 0          | 8          |
> +-------------------------------------------------------------------------------------------+------------+------------+
> 
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-lkp/202401191128.db8423f1-oliver.sang@xxxxxxxxx
> 
> 
> 
> The kernel config and materials to reproduce are available at:
> https://download.01.org/0day-ci/archive/20240119/202401191128.db8423f1-oliver.sang@xxxxxxxxx
> 
> 
> 
> [   19.037694][  T142] [drm] Initialized bochs-drm 1.0.0 20130925 for 0000:00:02.0 on minor 0
> [   19.038726][  T142] ------------[ cut here ]------------
> [   19.039197][  T142] bochs-drm 0000:00:02.0: drm_WARN_ON_ONCE(!dev->mode_config.poll_enabled)
> [   19.039241][  T142] WARNING: CPU: 0 PID: 142 at drivers/gpu/drm/drm_probe_helper.c:305 drm_kms_helper_poll_enable+0x329/0x410 [drm_kms_helper]
> [   19.040963][  T142] Modules linked in: parport(+) bochs(+) joydev serio_raw drm_vram_helper ata_piix(+) drm_ttm_helper ttm libata ipmi_devintf ipmi_msghandler drm_kms_helper i2c_piix4 fuse drm ip_tables
> [   19.042413][  T142] CPU: 0 PID: 142 Comm: systemd-udevd Not tainted 6.7.0-rc3-00770-g98a690eb11a5 #1
> [   19.043146][  T142] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
> [   19.043972][  T142] RIP: 0010:drm_kms_helper_poll_enable+0x329/0x410 [drm_kms_helper]
> [   19.044685][  T142] Code: 48 8b 6b 50 48 85 ed 74 41 48 89 df e8 30 e0 5d c3 48 c7 c1 e0 8c 4b c0 48 89 ea 48 c7 c7 40 8a 4b c0 48 89 c6 e8 77 a3 d3 c1 <0f> 0b e9 ae fd ff ff e8 9b c6 53 c2 e9 4c fd ff ff 48 8b 7c 24 08
> [   19.046268][  T142] RSP: 0000:ffffc900007ef1c0 EFLAGS: 00010286
> [   19.046755][  T142] RAX: 0000000000000000 RBX: ffff888121dc40c0 RCX: 0000000000000027
> [   19.047400][  T142] RDX: 0000000000000027 RSI: 0000000000000004 RDI: ffff8883af030848
> [   19.048042][  T142] RBP: ffff888121d84260 R08: 0000000000000001 R09: ffffed1075e06109
> [   19.048688][  T142] R10: ffff8883af03084b R11: 0000000000000001 R12: ffff88815688a7a0
> [   19.049362][  T142] R13: 1ffff920000fde3b R14: 0000000000000000 R15: 0000000000000003
> [   19.050001][  T142] FS:  0000000000000000(0000) GS:ffff8883af000000(0063) knlGS:00000000f7950b00
> [   19.050722][  T142] CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
> [   19.051259][  T142] CR2: 0000000058b17d6c CR3: 000000012463e000 CR4: 00000000000406f0
> [   19.051892][  T142] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [   19.052568][  T142] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [   19.053242][  T142] Call Trace:
> [   19.053531][  T142]  <TASK>
> [   19.053780][  T142]  ? __warn+0xcd/0x260
> [   19.054149][  T142]  ? drm_kms_helper_poll_enable+0x329/0x410 [drm_kms_helper]
> [   19.054787][  T142]  ? report_bug+0x267/0x2d0
> [   19.055173][  T142]  ? handle_bug+0x3c/0x70
> [   19.055523][  T142]  ? exc_invalid_op+0x17/0x40
> [   19.055904][  T142]  ? asm_exc_invalid_op+0x1a/0x20
> [   19.056332][  T142]  ? drm_kms_helper_poll_enable+0x329/0x410 [drm_kms_helper]
> [   19.056941][  T142]  ? drm_kms_helper_poll_fini+0x80/0x80 [drm_kms_helper]
> [   19.057567][  T142]  ? drm_modeset_lock+0xbf/0x2e0 [drm]
> [   19.058099][  T142]  drm_helper_probe_single_connector_modes+0x3b6/0xe70 [drm_kms_helper]
> [   19.058788][  T142]  ? __drm_helper_update_and_validate+0xc30/0xc30 [drm_kms_helper]
> [   19.059484][  T142]  ? __mutex_lock_slowpath+0x10/0x10
> [   19.059924][  T142]  drm_client_modeset_probe+0x3ab/0xef0 [drm]
> [   19.060491][  T142]  ? drm_client_firmware_config+0x1980/0x1980 [drm]
> [   19.061233][  T142]  __drm_fb_helper_initial_config_and_unlock+0xfa/0x7c0 [drm_kms_helper]
> [   19.061935][  T142]  ? __drm_fb_helper_find_sizes+0x1170/0x1170 [drm_kms_helper]
> [   19.062577][  T142]  ? mutex_lock+0xa3/0xf0
> [   19.062941][  T142]  ? __mutex_lock_slowpath+0x10/0x10
> [   19.063398][  T142]  ? mutex_lock+0xa3/0xf0
> [   19.063756][  T142]  ? __mutex_lock_slowpath+0x10/0x10
> [   19.064214][  T142]  drm_fbdev_generic_client_hotplug+0x161/0x210 [drm_kms_helper]
> [   19.064868][  T142]  drm_client_register+0x168/0x230 [drm]
> [   19.065410][  T142]  bochs_pci_probe+0x68f/0x8c0 [bochs]
> [   19.065860][  T142]  ? _raw_spin_lock_irqsave+0x8b/0xe0
> [   19.066318][  T142]  ? bochs_hw_init+0x650/0x650 [bochs]
> [   19.066821][  T142]  ? bochs_hw_init+0x650/0x650 [bochs]
> [   19.067346][  T142]  local_pci_probe+0xda/0x180
> [   19.067756][  T142]  pci_call_probe+0x160/0x510
> [   19.068172][  T142]  ? _raw_spin_lock+0x85/0xe0
> [   19.068575][  T142]  ? pci_dev_set_disconnected+0x30/0x30
> [   19.069059][  T142]  ? kernfs_add_one+0x2d4/0x440
> [   19.069483][  T142]  ? pci_assign_irq+0x8a/0x280
> [   19.069892][  T142]  ? pci_match_device+0x38c/0x690
> [   19.070338][  T142]  ? kernfs_put+0x1c/0x30
> [   19.070700][  T142]  pci_device_probe+0xef/0x230
> [   19.071112][  T142]  ? pci_dma_configure+0x11d/0x170
> [   19.071532][  T142]  really_probe+0x3d2/0xb40
> [   19.071911][  T142]  __driver_probe_device+0x18c/0x440
> [   19.072369][  T142]  ? klist_iter_init+0x70/0x70
> [   19.072770][  T142]  driver_probe_device+0x4a/0x120
> [   19.073209][  T142]  __driver_attach+0x1d2/0x490
> [   19.073609][  T142]  ? __device_attach_driver+0x260/0x260
> [   19.074084][  T142]  bus_for_each_dev+0x103/0x180
> [   19.074494][  T142]  ? bus_remove_file+0x40/0x40
> [   19.074887][  T142]  ? klist_add_tail+0x133/0x260
> [   19.075311][  T142]  bus_add_driver+0x29a/0x570
> [   19.075701][  T142]  driver_register+0x134/0x450
> [   19.076109][  T142]  ? 0xffffffffc06d6000
> [   19.076457][  T142]  do_one_initcall+0xa1/0x370
> [   19.076855][  T142]  ? trace_event_raw_event_initcall_level+0x1a0/0x1a0
> [   19.077428][  T142]  ? kasan_unpoison+0x44/0x70
> [   19.077823][  T142]  do_init_module+0x22e/0x720
> [   19.078222][  T142]  load_module+0x1826/0x25e0
> [   19.078603][  T142]  ? post_relocation+0x370/0x370
> [   19.079022][  T142]  ? kernel_read_file+0x243/0x820
> [   19.079431][  T142]  ? __x64_sys_fspick+0x2a0/0x2a0
> [   19.079844][  T142]  ? init_module_from_file+0xd1/0x130
> [   19.080295][  T142]  init_module_from_file+0xd1/0x130
> [   19.080725][  T142]  ? __ia32_sys_init_module+0xb0/0xb0
> [   19.081194][  T142]  ? userfaultfd_unmap_prep+0x3d0/0x3d0
> [   19.081657][  T142]  ? _raw_write_lock_irq+0xe0/0xe0
> [   19.082097][  T142]  idempotent_init_module+0x23b/0x660
> [   19.082540][  T142]  ? init_module_from_file+0x130/0x130
> [   19.082986][  T142]  ? __fget_light+0x57/0x3d0
> [   19.083386][  T142]  __ia32_sys_finit_module+0xbe/0x130
> [   19.083818][  T142]  __do_fast_syscall_32+0x61/0xd0
> [   19.084243][  T142]  do_fast_syscall_32+0x33/0x70
> [   19.084643][  T142]  entry_SYSENTER_compat_after_hwframe+0x70/0x7a
> [   19.085165][  T142] RIP: 0023:0xf7fb7579
> [   19.085503][  T142] Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
> [   19.086546][  T142] RSP: 002b:00000000ff888b1c EFLAGS: 00200206 ORIG_RAX: 000000000000015e
> [   19.087012][  T142] RAX: ffffffffffffffda RBX: 0000000000000012 RCX: 00000000f7fa1d41
> [   19.087442][  T142] RDX: 0000000000000000 RSI: 0000000056b70730 RDI: 0000000056b6c600
> [   19.087868][  T142] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> [   19.088324][  T142] R10: 0000000000000000 R11: 0000000000200206 R12: 0000000000000000
> [   19.088747][  T142] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> [   19.089176][  T142]  </TASK>
> [   19.089354][  T142] ---[ end trace 0000000000000000 ]---
> 
> 
> -- 
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki