On Thu, 09 May 2024, Steven Price <steven.price@xxxxxxx> wrote:
> On 29/04/2024 17:43, Jani Nikula wrote:
>> The driver date serves no useful purpose, because it's hardly ever
>> updated. The information is misleading at best.
>>
>> As described in Documentation/gpu/drm-internals.rst:
>>
>> The driver date, formatted as YYYYMMDD, is meant to identify the date
>> of the latest modification to the driver. However, as most drivers
>> fail to update it, its value is mostly useless. The DRM core prints it
>> to the kernel log at initialization time and passes it to userspace
>> through the DRM_IOCTL_VERSION ioctl.
>>
>> Stop printing the driver date at init, and start returning the empty
>> string "" as driver date through the DRM_IOCTL_VERSION ioctl.
>
> I agree with the idea of this, unfortuantly it breaks user space :(
>
> It's a bug in libdrm, but given this breaks existing user space I think
> we'll need to revert/reconsider.
>
> The issue is in drmGetVersion() [1]:
>
>> if (version->date_len)
>> version->date = drmMalloc(version->date_len + 1);
>
> So if date_len == 0, then version->date isn't populated (and isn't
> initialized at all). But then later on in drmCopyVersion() [2] the
> (unset) version->date is passed to strdup():
>
>> static void drmCopyVersion(drmVersionPtr d, const drm_version_t *s)
>> {
>> d->version_major = s->version_major;
>> d->version_minor = s->version_minor;
>> d->version_patchlevel = s->version_patchlevel;
>> d->name_len = s->name_len;
>> d->name = strdup(s->name);
>> d->date_len = s->date_len;
>> d->date = strdup(s->date);
>> d->desc_len = s->desc_len;
>> d->desc = strdup(s->desc);
>> }
>
> Which then segfaults if the uninitialized value points off somewhere
> bad. And this does happen (my test setup reproduced this).
Thanks for the report!
> A simple fix is to make sure the string isn't empty - so return
> "unknown" or just a space, or even "\0".
I don't think "\0" works, because strlen() will still return 0 for it.
I went ahead with "0", because that's already been used by virtio until
now. Fix at [1].
BR,
Jani.
[1] https://lore.kernel.org/r/20240510090951.3398882-1-jani.nikula@xxxxxxxxx
>
> Steve
>
> [1]
> https://gitlab.freedesktop.org/mesa/drm/-/blob/7c5c742de8a8b577654964635f05d7033c92ee53/xf86drm.c#L1393
>
> [2]
> https://gitlab.freedesktop.org/mesa/drm/-/blob/7c5c742de8a8b577654964635f05d7033c92ee53/xf86drm.c#L1352
>
>
>> The driver date initialization in drivers and the struct drm_driver date
>> member can be removed in follow-up.
>>
>> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
>>
>> ---
>>
>> The below approximates when each driver's date was last updated.
>>
>> $ git grepblame "\(\.date = \".*\"\|#define.*DRIVER_DATE\)" -- drivers/gpu drivers/accel
>> fe77368c0f3e0 drivers/accel/habanalabs/common/habanalabs_drv.c 94 (Tomer Tayar 2023-02-19 11:58:46 +0200 104) .date = "20190505",
>> 35b137630f08d drivers/accel/ivpu/ivpu_drv.h 20 (Jacek Lawrynowicz 2023-01-17 10:27:17 +0100 24) #define DRIVER_DATE "20230117"
>> d38ceaf99ed01 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.h 43 (Alex Deucher 2015-04-20 16:55:21 -0400 43) #define DRIVER_DATE "20150101"
>> 61f1c4a8ab757 drivers/gpu/drm/arm/display/komeda/komeda_kms.c 51 (james qian wang (Arm Technology China) 2019-01-03 11:41:30 +0000 64) .date = "20181101",
>> 8e22d79240d95 drivers/gpu/drm/arm/hdlcd_drv.c 343 (Liviu Dudau 2015-04-02 19:48:39 +0100 234) .date = "20151021",
>> ad49f8602fe88 drivers/gpu/drm/arm/malidp_drv.c 232 (Liviu Dudau 2016-03-07 10:00:53 +0000 571) .date = "20160106",
>> 4f2a8f5898ecd drivers/gpu/drm/aspeed/aspeed_gfx_drv.c 208 (Joel Stanley 2019-04-03 10:49:08 +1030 253) .date = "20180319",
>> 312fec1405dd5 drivers/gpu/drm/ast/ast_drv.h 46 (Dave Airlie 2012-02-29 13:40:04 +0000 46) #define DRIVER_DATE "20120228"
>> 1a396789f65a2 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c 504 (Boris Brezillon 2015-01-06 11:13:28 +0100 741) .date = "20141504",
>> 9913f74fe1570 drivers/gpu/drm/exynos/exynos_drm_drv.c 37 (Marek Szyprowski 2018-05-10 08:46:36 +0900 37) #define DRIVER_DATE "20180330"
>> f90cd811ae7a3 drivers/gpu/drm/gma500/psb_drv.h 43 (Arthur Borsboom 2014-03-15 22:12:17 +0100 29) #define DRIVER_DATE "20140314"
>> 1053d01864937 drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c 1070 (Xu YiPing 2019-08-20 23:06:19 +0000 930) .date = "20150718",
>> 76c56a5affeba drivers/gpu/drm/hyperv/hyperv_drm_drv.c 22 (Deepak Rawat 2021-05-27 04:22:28 -0700 22) #define DRIVER_DATE "2020"
>> 3570bd989acc6 drivers/gpu/drm/i915/i915_driver.h 18 (Jani Nikula 2023-09-29 12:43:23 +0300 18) #define DRIVER_DATE "20230929"
>> 4babef0708656 drivers/gpu/drm/imagination/pvr_drv.h 12 (Sarah Walker 2023-11-22 16:34:26 +0000 12) #define PVR_DRIVER_DATE "20230904"
>> c87e859cdeb5d drivers/gpu/drm/imx/lcdc/imx-lcdc.c 361 (Marian Cichy 2023-03-06 12:52:49 +0100 353) .date = "20200716",
>> eb92830cdbc23 drivers/gpu/drm/kmb/kmb_drv.h 19 (Edmund Dea 2020-08-26 13:17:29 -0700 19) #define DRIVER_DATE "20210223"
>> f39db26c54281 drivers/gpu/drm/loongson/lsdc_drv.c 28 (Sui Jingfeng 2023-06-15 22:36:12 +0800 28) #define DRIVER_DATE "20220701"
>> 5fc537bfd0003 drivers/gpu/drm/mcde/mcde_drv.c 247 (Linus Walleij 2019-05-24 11:20:19 +0200 210) .date = "20180529",
>> 119f5173628aa drivers/gpu/drm/mediatek/mtk_drm_drv.c 36 (CK Hu 2016-01-04 18:36:34 +0100 34) #define DRIVER_DATE "20150513"
>> 414c453106255 drivers/gpu/drm/mgag200/mgag200_drv.h 34 (Dave Airlie 2012-04-17 15:01:25 +0100 31) #define DRIVER_DATE "20110418"
>> 77145f1cbdf8d drivers/gpu/drm/nouveau/nouveau_drm.h 9 (Ben Skeggs 2012-07-31 16:16:21 +1000 10) #define DRIVER_DATE "20120801"
>> cd5351f4d2b1b drivers/staging/omapdrm/omap_drv.c 27 (Rob Clark 2011-11-12 12:09:40 -0600 31) #define DRIVER_DATE "20110917"
>> 4bdca11507928 drivers/gpu/drm/panthor/panthor_drv.c 1371 (Boris Brezillon 2024-02-29 17:22:25 +0100 1386) .date = "20230801",
>> bed41005e6174 drivers/gpu/drm/pl111/pl111_drv.c 157 (Tom Cooksey 2017-04-12 20:17:46 -0700 222) .date = "20170317",
>> f64122c1f6ade drivers/gpu/drm/qxl/qxl_drv.h 52 (Dave Airlie 2013-02-25 14:47:55 +1000 57) #define DRIVER_DATE "20120117"
>> c0beb2a723d69 drivers/char/drm/radeon_drv.h 41 (Dave Airlie 2008-05-28 13:52:28 +1000 46) #define DRIVER_DATE "20080528"
>> 2048e3286f347 drivers/gpu/drm/rockchip/rockchip_drm_drv.c 34 (Mark Yao 2014-08-22 18:36:26 +0800 41) #define DRIVER_DATE "20140818"
>> a61732e808672 drivers/gpu/drm/solomon/ssd130x.c 38 (Javier Martinez Canillas 2022-02-14 14:37:07 +0100 41) #define DRIVER_DATE "20220131"
>> 43531edd53f07 drivers/gpu/drm/sprd/sprd_drm.c 26 (Kevin Tang 2021-12-07 22:27:13 +0800 26) #define DRIVER_DATE "20200201"
>> 9bbf86fe874cc drivers/gpu/drm/sti/sti_drm_drv.c 24 (Benjamin Gaignard 2014-07-31 09:39:11 +0200 31) #define DRIVER_DATE "20140601"
>> af5125de7a0e8 drivers/gpu/drm/stm/drv.c 57 (Philippe CORNU 2017-07-20 14:05:51 +0200 62) .date = "20170330",
>> d8f4a9eda0067 drivers/gpu/drm/tegra/drm.c 22 (Thierry Reding 2012-11-15 21:28:22 +0000 37) #define DRIVER_DATE "20120330"
>> 51dacf208988e drivers/gpu/drm/arc/arcpgu_drv.c 193 (Carlos Palminha 2016-02-19 15:30:26 +0300 368) .date = "20160219",
>> ab3e023b1b4c9 drivers/gpu/drm/cirrus/cirrus.c 45 (Gerd Hoffmann 2019-04-05 11:52:19 +0200 50) #define DRIVER_DATE "2019"
>> e4f86e4371644 drivers/gpu/drm/gm12u320/gm12u320.c 33 (Hans de Goede 2019-07-21 15:25:25 +0200 36) #define DRIVER_DATE "2019"
>> c8a17756c4258 drivers/gpu/drm/tiny/ofdrm.c 27 (Thomas Zimmermann 2022-10-11 17:07:08 +0200 27) #define DRIVER_DATE "20220501"
>> 11e8f5fd223bd drivers/gpu/drm/tiny/simpledrm.c 26 (Thomas Zimmermann 2021-04-30 12:58:35 +0200 33) #define DRIVER_DATE "20200625"
>> 179c02fe90a41 drivers/gpu/drm/tve200/tve200_drv.c 141 (Linus Walleij 2017-08-20 12:05:55 +0200 147) .date = "20170703",
>> 5320918b9a878 drivers/gpu/drm/udl/udl_drv.h 21 (Dave Airlie 2010-12-15 07:14:24 +1000 29) #define DRIVER_DATE "20120220"
>> 57692c94dcbe9 drivers/gpu/drm/v3d/v3d_drv.c 31 (Eric Anholt 2018-04-30 11:10:58 -0700 34) #define DRIVER_DATE "20180419"
>> dd55d44f40841 drivers/staging/vboxvideo/vbox_drv.h 55 (Hans de Goede 2017-07-06 16:06:01 +0200 28) #define DRIVER_DATE "20130823"
>> c8b75bca92cbf drivers/gpu/drm/vc4/vc4_drv.c 23 (Eric Anholt 2015-03-02 13:01:12 -0800 48) #define DRIVER_DATE "20140616"
>> 502e95c667850 drivers/gpu/drm/vgem/vgem_drv.c 41 (Zach Reizner 2015-03-04 16:33:41 -0800 50) #define DRIVER_DATE "20120112"
>> dc5698e80cf72 drivers/gpu/drm/virtio/virtgpu_drv.h 44 (Dave Airlie 2013-09-09 10:02:56 +1000 48) #define DRIVER_DATE "0"
>> 1c7c5fd916a0f drivers/gpu/drm/vkms/vkms_drv.c 16 (Haneen Mohammed 2018-05-14 17:33:46 +0300 36) #define DRIVER_DATE "20180514"
>> 94eb7de6f4bec drivers/gpu/drm/vmwgfx/vmwgfx_drv.h 57 (Zack Rusin 2021-12-08 21:49:24 -0500 59) #define VMWGFX_DRIVER_DATE "20211206"
>> dd08ebf6c3525 drivers/gpu/drm/xe/xe_drv.h 13 (Matthew Brost 2023-03-30 17:31:57 -0400 13) #define DRIVER_DATE "20201103"
>> ---
>> Documentation/gpu/drm-internals.rst | 10 ++--------
>> drivers/gpu/drm/drm_drv.c | 4 ++--
>> drivers/gpu/drm/drm_ioctl.c | 5 +++--
>> include/drm/drm_drv.h | 2 +-
>> 4 files changed, 8 insertions(+), 13 deletions(-)
>>
>> diff --git a/Documentation/gpu/drm-internals.rst b/Documentation/gpu/drm-internals.rst
>> index 335de7fcddee..11d9a5730fb2 100644
>> --- a/Documentation/gpu/drm-internals.rst
>> +++ b/Documentation/gpu/drm-internals.rst
>> @@ -57,8 +57,8 @@ is larger than the driver minor, the DRM_IOCTL_SET_VERSION call will
>> return an error. Otherwise the driver's set_version() method will be
>> called with the requested version.
>>
>> -Name, Description and Date
>> -~~~~~~~~~~~~~~~~~~~~~~~~~~
>> +Name and Description
>> +~~~~~~~~~~~~~~~~~~~~
>>
>> char \*name; char \*desc; char \*date;
>> The driver name is printed to the kernel log at initialization time,
>> @@ -69,12 +69,6 @@ The driver description is a purely informative string passed to
>> userspace through the DRM_IOCTL_VERSION ioctl and otherwise unused by
>> the kernel.
>>
>> -The driver date, formatted as YYYYMMDD, is meant to identify the date of
>> -the latest modification to the driver. However, as most drivers fail to
>> -update it, its value is mostly useless. The DRM core prints it to the
>> -kernel log at initialization time and passes it to userspace through the
>> -DRM_IOCTL_VERSION ioctl.
>> -
>> Module Initialization
>> ---------------------
>>
>> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
>> index 535b624d4c9d..162f50c78d71 100644
>> --- a/drivers/gpu/drm/drm_drv.c
>> +++ b/drivers/gpu/drm/drm_drv.c
>> @@ -947,9 +947,9 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
>> }
>> drm_panic_register(dev);
>>
>> - DRM_INFO("Initialized %s %d.%d.%d %s for %s on minor %d\n",
>> + DRM_INFO("Initialized %s %d.%d.%d for %s on minor %d\n",
>> driver->name, driver->major, driver->minor,
>> - driver->patchlevel, driver->date,
>> + driver->patchlevel,
>> dev->dev ? dev_name(dev->dev) : "virtual device",
>> dev->primary ? dev->primary->index : dev->accel->index);
>>
>> diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
>> index e368fc084c77..89feb7306e47 100644
>> --- a/drivers/gpu/drm/drm_ioctl.c
>> +++ b/drivers/gpu/drm/drm_ioctl.c
>> @@ -529,9 +529,10 @@ int drm_version(struct drm_device *dev, void *data,
>> version->version_patchlevel = dev->driver->patchlevel;
>> err = drm_copy_field(version->name, &version->name_len,
>> dev->driver->name);
>> +
>> + /* Driver date is deprecated. Return the empty string. */
>> if (!err)
>> - err = drm_copy_field(version->date, &version->date_len,
>> - dev->driver->date);
>> + err = drm_copy_field(version->date, &version->date_len, "");
>> if (!err)
>> err = drm_copy_field(version->desc, &version->desc_len,
>> dev->driver->desc);
>> diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
>> index 8878260d7529..cd37936c3926 100644
>> --- a/include/drm/drm_drv.h
>> +++ b/include/drm/drm_drv.h
>> @@ -411,7 +411,7 @@ struct drm_driver {
>> char *name;
>> /** @desc: driver description */
>> char *desc;
>> - /** @date: driver date */
>> + /** @date: driver date, unused, to be removed */
>> char *date;
>>
>> /**
>
--
Jani Nikula, Intel
