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android-review.linaro.org / kernel / common / refs/tags/android13-5.15-2023-02_r4
tag9193b65cfbe1d5f8427904678fa050497962a451
taggerHoward Chen <howardsoc@google.com>Fri Apr 14 12:04:21 2023 +0800
objectae16e9c4dc548396d1de62e1bea1e132cdbf7f35 
android13-5.15 February 2023 release 4

Artifacts:
  https://ci.android.com/builds/submitted/9935970/kernel_aarch64/latest
commitae16e9c4dc548396d1de62e1bea1e132cdbf7f35[log] [tgz]
authorVictor Hassan <victor@allwinnertech.com>Wed Apr 12 11:35:14 2023 +0800
committerYu Liu <liuyu@allwinnertech.com>Thu Apr 13 09:47:19 2023 +0000
treebb2e0a69bbcde3841ab9933ab76b6d276f439d02
parentfe86c885b0db51c8c67a44b5c17650377a2055e8 [diff]
FROMLIST: [PATCH v2] tick/broadcast: Do not set oneshot_mask except was_periodic was true

If a broadcast timer is registered after the system switched to oneshot
mode, a hang_task err could occur like that:

INFO: task kworker/u15:0:7 blocked for more than 120 seconds.
      Tainted: G            E     5.15.41-android13-8-00002-xxx #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u16:0   state:D stack: 9808 pid:  7 ppid: 2 flags:0x00000008
Workqueue: events_unbound deferred_probe_work_func.cfi_jt
Call trace:
 __switch_to+0y240/0x490
 __schedule+0x620/0xafc
 schedule+0x110/0x204
 schedule_hrtimeout_range_clock+0x9c/0x118
 usleep_range_state+0x150/0x1ac
 _regulator_do_enable+0x528/0x878
 set_machine_constraints+0x6a0/0xf2c
 regulator_register+0x3ac/0x7ac
 devm_regulator_register+0xbc/0x120
 pmu_ext_regulator_probe+0xb0/0x1b4 [pmu_ext_regulator]
 platform_probe+0x70/0x194
 really_probe+0x320/0x68c
 __driver_probe_device+0x204/0x260
 driver_probe_device+0x48/0x1e0

When the new broadcast timer was registered after the system switched
to oneshot mode, the broadcast timer was not used as periodic. If the
oneshot mask was set incorrectly, all cores which did not enter cpu_idle
state can't enter cpu_idle normally, causing the hrtimer mechanism to
break. Like:

* CPU 1 stop its tick, next event is in one hour. It calls
  tick_broadcast_enter() and goes to sleep.
* CPU 1 gets an interrupt that enqueues a new timer expiring in the next jiffy
  (note it's not yet actually programmed in the tick device)
* CPU 1 call tick_broadcast_exit().
* CPU 0 registers new broadcast device and sets CPU 1 in tick_broadcast_oneshot_mask
* CPU 0 runs the broadcast callback, sees that the next timer for CPU 1
  is in one hour (because the recently enqueued timer for CPU 1 hasn't been programmed
  yet), so it programs the broadcast to that 1 hour deadline.
* CPU 1 runs tick_nohz_idle_stop_tick() which eventually writes and program
  dev->next_event to next jiffy
* CPU 1 runs into cpuidle_enter_state(), and tick_broadcast_enter() is ignored because
  the CPU is already in tick_broadcast_oneshot_mask, so the dev->next_event
  change isn't propagated to broadcast.
* CPU 1 goes to sleep for 1 hour.

This patch fixes the issue by moving the update action about oneshot
mask to a more strict conditions. The tick_broadcast_setup_oneshot would
be called in two typical condition, and they all will work.

1. tick_handle_periodic -> tick_broadcast_setup_oneshot

The origin broadcast was periodic, so it can set the oneshot_mask bits
for those waiting for periodic broadcast and program the broadcast timer
to fire.

2. tick_install_broadcast_device -> tick_broadcast_setup_oneshot

The origin broadcast was oneshot, so the cores which enter the cpu_idle
already used the oneshot_mask bits. It is unnecessary to update the
oneshot_mask.

Fixes: 9c336c9935cf ("tick/broadcast: Allow late registered device to enter oneshot mode")

Reviewed-by: Frederic Weisbecker <frederic@kernel.org>

Signed-off-by: Victor Hassan <victor@allwinnertech.com>

Bug: 274731061
Bug: 278033842
Link: https://lore.kernel.org/lkml/20230412003425.11323-1-victor@allwinnertech.com/t/
Change-Id: Ie5f27007a701ea483285ba5751ce6251ad8f5da6
Signed-off-by: liuyu <liuyu@allwinnertech.com>
(cherry picked from commit ec96f224148a6e6a4e8d462d99e1ac37d7394cea)
1 file changed
tree: bb2e0a69bbcde3841ab9933ab76b6d276f439d02
  1. android/
  2. arch/
  3. block/
  4. certs/
  5. crypto/
  6. Documentation/
  7. drivers/
  8. fs/
  9. include/
  10. init/
  11. io_uring/
  12. ipc/
  13. kernel/
  14. lib/
  15. LICENSES/
  16. mm/
  17. net/
  18. samples/
  19. scripts/
  20. security/
  21. sound/
  22. tools/
  23. usr/
  24. virt/
  25. .clang-format
  26. .cocciconfig
  27. .get_maintainer.ignore
  28. .gitattributes
  29. .gitignore
  30. .mailmap
  31. BUILD.bazel
  32. build.config.aarch64
  33. build.config.allmodconfig
  34. build.config.allmodconfig.aarch64
  35. build.config.allmodconfig.arm
  36. build.config.allmodconfig.x86_64
  37. build.config.amlogic
  38. build.config.arm
  39. build.config.common
  40. build.config.constants
  41. build.config.db845c
  42. build.config.gce.x86_64
  43. build.config.gki
  44. build.config.gki-debug.aarch64
  45. build.config.gki-debug.x86_64
  46. build.config.gki.aarch64
  47. build.config.gki.aarch64.fips140
  48. build.config.gki.x86_64
  49. build.config.gki_kasan
  50. build.config.gki_kasan.aarch64
  51. build.config.gki_kasan.x86_64
  52. build.config.gki_kprobes
  53. build.config.gki_kprobes.aarch64
  54. build.config.gki_kprobes.x86_64
  55. build.config.khwasan
  56. build.config.rockpi4
  57. build.config.x86_64
  58. COPYING
  59. CREDITS
  60. Kbuild
  61. Kconfig
  62. Kconfig.ext
  63. MAINTAINERS
  64. Makefile
  65. OWNERS
  66. README
  67. README.md
README.md

How do I submit patches to Android Common Kernels

  1. BEST: Make all of your changes to upstream Linux. If appropriate, backport to the stable releases. These patches will be merged automatically in the corresponding common kernels. If the patch is already in upstream Linux, post a backport of the patch that conforms to the patch requirements below.

    • Do not send patches upstream that contain only symbol exports. To be considered for upstream Linux, additions of EXPORT_SYMBOL_GPL() require an in-tree modular driver that uses the symbol -- so include the new driver or changes to an existing driver in the same patchset as the export.
    • When sending patches upstream, the commit message must contain a clear case for why the patch is needed and beneficial to the community. Enabling out-of-tree drivers or functionality is not not a persuasive case.

  2. LESS GOOD: Develop your patches out-of-tree (from an upstream Linux point-of-view). Unless these are fixing an Android-specific bug, these are very unlikely to be accepted unless they have been coordinated with kernel-team@android.com. If you want to proceed, post a patch that conforms to the patch requirements below.

Common Kernel patch requirements

  • All patches must conform to the Linux kernel coding standards and pass scripts/checkpatch.pl
  • Patches shall not break gki_defconfig or allmodconfig builds for arm, arm64, x86, x86_64 architectures (see https://source.android.com/setup/build/building-kernels)
  • If the patch is not merged from an upstream branch, the subject must be tagged with the type of patch: UPSTREAM:, BACKPORT:, FROMGIT:, FROMLIST:, or ANDROID:.
  • All patches must have a Change-Id: tag (see https://gerrit-review.googlesource.com/Documentation/user-changeid.html)
  • If an Android bug has been assigned, there must be a Bug: tag.
  • All patches must have a Signed-off-by: tag by the author and the submitter

Additional requirements are listed below based on patch type

Requirements for backports from mainline Linux: UPSTREAM:, BACKPORT:

  • If the patch is a cherry-pick from Linux mainline with no changes at all
    • tag the patch subject with UPSTREAM:.
    • add upstream commit information with a (cherry picked from commit ...) line
    • Example:
      • if the upstream commit message is
        important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>
  • then Joe Smith would upload the patch for the common kernel as
        UPSTREAM: important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

        Bug: 135791357
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        (cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
        Signed-off-by: Joe Smith <joe.smith@foo.org>
  • If the patch requires any changes from the upstream version, tag the patch with BACKPORT: instead of UPSTREAM:.
    • use the same tags as UPSTREAM:
    • add comments about the changes under the (cherry picked from commit ...) line
    • Example:
        BACKPORT: important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

        Bug: 135791357
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        (cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
        [joe: Resolved minor conflict in drivers/foo/bar.c ]
        Signed-off-by: Joe Smith <joe.smith@foo.org>

Requirements for other backports: FROMGIT:, FROMLIST:,

  • If the patch has been merged into an upstream maintainer tree, but has not yet been merged into Linux mainline
    • tag the patch subject with FROMGIT:
    • add info on where the patch came from as (cherry picked from commit <sha1> <repo> <branch>). This must be a stable maintainer branch (not rebased, so don't use linux-next for example).
    • if changes were required, use BACKPORT: FROMGIT:
    • Example:
      • if the commit message in the maintainer tree is
        important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>
  • then Joe Smith would upload the patch for the common kernel as
        FROMGIT: important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

        Bug: 135791357
        (cherry picked from commit 878a2fd9de10b03d11d2f622250285c7e63deace
         https://git.kernel.org/pub/scm/linux/kernel/git/foo/bar.git test-branch)
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        Signed-off-by: Joe Smith <joe.smith@foo.org>
  • If the patch has been submitted to LKML, but not accepted into any maintainer tree
    • tag the patch subject with FROMLIST:
    • add a Link: tag with a link to the submittal on lore.kernel.org
    • add a Bug: tag with the Android bug (required for patches not accepted into a maintainer tree)
    • if changes were required, use BACKPORT: FROMLIST:
    • Example:
        FROMLIST: important patch from upstream

        This is the detailed description of the important patch

        Signed-off-by: Fred Jones <fred.jones@foo.org>

        Bug: 135791357
        Link: https://lore.kernel.org/lkml/20190619171517.GA17557@someone.com/
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        Signed-off-by: Joe Smith <joe.smith@foo.org>

Requirements for Android-specific patches: ANDROID:

  • If the patch is fixing a bug to Android-specific code
    • tag the patch subject with ANDROID:
    • add a Fixes: tag that cites the patch with the bug
    • Example:
        ANDROID: fix android-specific bug in foobar.c

        This is the detailed description of the important fix

        Fixes: 1234abcd2468 ("foobar: add cool feature")
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        Signed-off-by: Joe Smith <joe.smith@foo.org>
  • If the patch is a new feature
    • tag the patch subject with ANDROID:
    • add a Bug: tag with the Android bug (required for android-specific features)