Re: [alsa-devel] [RFC PATCH 0/7] Fix year 2038 issue for sound subsystem

Hi Takashi,

On 22 September 2017 at 12:07, Takashi Sakamoto o-takashi@sakamocchi.jp wrote:

Hi,

On Sep 21 2017 15:18, Baolin Wang wrote:

...

Since many structures will use timespec type variables to record time stamp in uapi/asound.h, which are not year 2038 safe on 32bit system. This patchset tries to introduce new structures removing timespec type to compatible native mode and compat mode.

Moreover this patchset also converts the internal structrures to use timespec64 type and related APIs.

Baolin Wang (7): sound: Replace timespec with timespec64 sound: core: Avoid using timespec for struct snd_pcm_status sound: core: Avoid using timespec for struct snd_pcm_sync_ptr sound: core: Avoid using timespec for struct snd_rawmidi_status sound: core: Avoid using timespec for struct snd_timer_status uapi: sound: Avoid using timespec for struct snd_ctl_elem_value sound: core: Avoid using timespec for struct snd_timer_tread

include/sound/pcm.h | 113 ++++++++- include/sound/timer.h | 4 +- include/uapi/sound/asound.h | 15 +- sound/core/pcm.c | 14 +- sound/core/pcm_compat.c | 466 +++++++++++++++++++++++++++++-------- sound/core/pcm_lib.c | 33 +-- sound/core/pcm_native.c | 227 ++++++++++++++---- sound/core/rawmidi.c | 74 +++++- sound/core/rawmidi_compat.c | 90 +++++-- sound/core/timer.c | 247 ++++++++++++++++---- sound/core/timer_compat.c | 25 +- sound/pci/hda/hda_controller.c | 10 +- sound/soc/intel/skylake/skl-pcm.c | 4 +- 13 files changed, 1046 insertions(+), 276 deletions(-)

I'm a minor Takashi in this subsystem and not those who you'd like to talk about this issue. But I have interests in it and would like to assist you, as long as I can do for it.

Thanks a lot.

As a nitpicking, your patchset brings compilation error at configurations for x86, and x86-64 with x32 ABI support.

## x86-64 architecture and amd64 ABI support CONFIG_64BIT=y CONFIG_X86_64=y

Success.

## x86-64 architecture and amd64/x32 ABI support CONFIG_64BIT=y CONFIG_X86_64=y CONFIG_X86_X32=y

sound/core/timer_compat.c:124:54: error: array type has incomplete element
type 'struct snd_timer_status32'
  SNDRV_TIMER_IOCTL_STATUS32 = _IOW('T', 0x14, struct snd_timer_status32),

This error comes from a commit 1229cccbefe7 ('sound: core: Avoid using timespec for struct snd_timer_status').

sound/core/pcm_compat.c: In function 'snd_pcm_ioctl_sync_ptr_compat':
sound/core/pcm_compat.c:623:9: error: assignment from incompatible pointer
type [-Werror=incompatible-pointer-types]
  status = runtime->status;
         ^
sound/core/pcm_compat.c: In function 'snd_pcm_ioctl_sync_ptr_x32':
sound/core/pcm_compat.c:711:9: error: assignment from incompatible pointer
type [-Werror=incompatible-pointer-types]
  status = runtime->status;

This error comes from a commit 947c463adc00('sound: core: Avoid using timespec for struct snd_pcm_status').

## x86 architecture and i386 ABI support CONFIG_X86_32=y

sound/core/pcm_native.c: In function 'snd_pcm_common_ioctl':
sound/core/pcm_native.c:3065:2: error: duplicate case value
  case SNDRV_PCM_IOCTL_SYNC_PTR64:
  ^~~~
sound/core/pcm_native.c:3062:2: error: previously used here
  case SNDRV_PCM_IOCTL_SYNC_PTR32:

This error comes from a commit c0513348a7b39 ('sound: core: Avoid using timespec for struct snd_pcm_sync_ptr').

Your patchset brought conflicts to 'for-next' branch in a repository which Iwai-san maintains[1]. I rebased your patchset on a commit 729fbfc92a45 ('ALSA: line6: add support for POD HD DESKTOP') which is a HEAD of 'for-next' branch and pushed into my repository on github[2].

I respect your work for this issue, however it's better to check whether your patchset is buildable or not on major configurations before posting.

Sorry for the building errors, since I can not build CONFIG_COMPAT mode on my arm32 platform. But I will try to fix these build errors in next version. This RFC patchset, I just want to show how to fix the y2038 issue and to see if it is on the correct way. Sorry for the building errors again.

I note that at a development period for v4.5 kernel, ALSA developers (mainly Iwai-san) fixed x32 ABI compatibility bugs. Then I prepared for a rough set of test for ioctl command[3] to check his work. The set will partly help your work, I think (but it's really rough).

Ah, thanks.

I need more time for reviewing. At least, this week is for recovery from my tough work to rewrite aplay[4].

Understood. Very appreciated for your comments.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git [2] https://github.com/takaswie/sound/tree/topic/year2038-rfc1 [3] https://github.com/takaswie/alsa-ioctl-test/ [4] [alsa-devel] [RFCv2][PATCH 00/38] alsa-utils: axfer: rewrite aplay http://mailman.alsa-project.org/pipermail/alsa-devel/2017-September/125574.h...

Thanks

Takashi Sakamoto