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Filename Latest commit message Latest commit date
Suren Baghdasaryan c797384edc ANDROID: kthread: break dependency between worker->lock and task_struct->pi_lock
A number of kthread-related functions indirectly take task_struct->pi_lock
while holding worker->lock in the call chain like this:
    spin_lock(&worker->lock)
    kthread_insert_work
    wake_up_process
    try_to_wake_up
    raw_spin_lock_irqsave(&p->pi_lock, flags)

This lock dependency exists whenever kthread_insert_work is called either
directly or indirectly via __kthread_queue_delayed_work in the following
functions:
    kthread_queue_work
    kthread_delayed_work_timer_fn
    kthread_queue_delayed_work
    kthread_flush_work
    kthread_mod_delayed_work

This creates possibilities for circular dependencies like the one reported
at [1]. Break this lock dependency by moving task wakeup after worker->lock
has been released.

[1]: https://lore.kernel.org/lkml/CAJuCfpG4NkhpQvZjgXZ_3gm6Hf1QgN_eUOQ8iX9Cv1k9whLwSQ@mail.gmail.com

Reported-by: Ke Wang <ke.wang@unisoc.com>
Reported-by: Shakeel Butt <shakeelb@google.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>

Link: https://lkml.org/lkml/2020/5/4/1148
Cherry picked instead of commit 461daba06bdcb9c7a3f92b9bbd110e1f7d093ffc
as an alternative solution for the lockdep error that does not break KMI.
Bug: 174875976
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: I2478847f66c85dca953846cd77955928d690c97c
2020-12-08 11:48:06 -08:00
android ANDROID: ABI: add symbols of drm_atomic_helper_setup_commit to unisoc 2020-12-08 09:45:12 +08:00
arch ANDROID: GKI: enable CONFIG_SUN4I_TIMER 2020-11-19 05:51:03 +00:00
block UPSTREAM: block: fix get_max_io_size() 2020-11-18 15:26:38 +00:00
certs
crypto Revert "ANDROID: Revert: Merge 5.4.60 into android11-5.4" 2020-08-23 13:12:51 +02:00
Documentation UPSTREAM: Documentation: arm64: document support for the AMU extension 2020-11-18 17:58:21 +00:00
drivers UPSTREAM: HID: core: Correctly handle ReportSize being zero 2020-12-04 23:36:51 +00:00
fs UPSTREAM: fscrypt: restrict IV_INO_LBLK_* to AES-256-XTS 2020-11-14 16:29:45 +01:00
include UPSTREAM: HID: core: Sanitize event code and type when mapping input 2020-12-04 23:13:47 +00:00
init ANDROID: GKI: add fields required to enable CONFIG_TRANSPARENT_HUGEPAGE 2020-10-15 17:21:03 +02:00
ipc Revert "ANDROID: vfs: Add permission2 for filesystems with per mount permissions" 2020-05-29 14:48:37 +02:00
kernel ANDROID: kthread: break dependency between worker->lock and task_struct->pi_lock 2020-12-08 11:48:06 -08:00
lib Revert "ANDROID: Revert: Merge 5.4.60 into android11-5.4" 2020-08-23 13:12:51 +02:00
LICENSES
mm UPSTREAM: mm/sl[uo]b: export __kmalloc_track(_node)_caller 2020-11-02 16:12:00 +00:00
net UPSTREAM: net: fix fraglist segmentation reference count leak 2020-11-14 16:55:56 +01:00
samples This is the 5.4.59 stable release 2020-08-19 08:40:57 +02:00
scripts FROMLIST: scripts: merge_config: add strict mode to fail upon any redefinition 2020-12-03 07:16:08 +00:00
security UPSTREAM: selinux: ensure the policy has been loaded before reading the sidtab stats 2020-11-14 16:56:33 +01:00
sound This is the 5.4.61 stable release 2020-08-26 11:11:38 +02:00
tools This is the 5.4.61 stable release 2020-08-26 11:11:38 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set 2020-08-26 10:41:08 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
build.config.aarch64 ANDROID: add compat cross compiler 2020-04-27 20:20:28 -07:00
build.config.allmodconfig ANDROID: GKI: Fix up "do not export symbol_get/put()" commit 2020-08-01 14:28:51 +02:00
build.config.allmodconfig.aarch64 ANDROID: drop KERNEL_DIR setting in build.config.common 2020-09-25 14:50:31 +08:00
build.config.allmodconfig.arm ANDROID: drop KERNEL_DIR setting in build.config.common 2020-09-25 14:50:31 +08:00
build.config.allmodconfig.x86_64 ANDROID: drop KERNEL_DIR setting in build.config.common 2020-09-25 14:50:31 +08:00
build.config.arm ANDROID: Add build.config files for ARM 32-bit 2020-03-15 22:51:11 +00:00
build.config.common ANDROID: Update the KMI_GENERATION after KMI changes on October 31 2020-10-31 12:37:57 +01:00
build.config.db845c ANDROID: drop KERNEL_DIR setting in build.config.common 2020-09-25 14:50:31 +08:00
build.config.gki ANDROID: gki: Removed cf modules from gki_defconfig 2020-01-31 16:34:58 -08:00
build.config.gki-debug.aarch64 ANDROID: drop KERNEL_DIR setting in build.config.common 2020-09-25 14:50:31 +08:00
build.config.gki-debug.x86_64 ANDROID: drop KERNEL_DIR setting in build.config.common 2020-09-25 14:50:31 +08:00
build.config.gki.aarch64 ANDROID: GKI: initial upload list for exynosauto soc 2020-11-12 17:32:06 +09:00
build.config.gki.x86_64 ANDROID: drop KERNEL_DIR setting in build.config.common 2020-09-25 14:50:31 +08:00
build.config.gki_kasan ANDROID: drop KERNEL_DIR setting in build.config.common 2020-09-25 14:50:31 +08:00
build.config.gki_kasan.aarch64 ANDROID: drop KERNEL_DIR setting in build.config.common 2020-09-25 14:50:31 +08:00
build.config.gki_kasan.x86_64 ANDROID: drop KERNEL_DIR setting in build.config.common 2020-09-25 14:50:31 +08:00
build.config.hikey960 ANDROID: drop KERNEL_DIR setting in build.config.common 2020-09-25 14:50:31 +08:00
build.config.x86_64
COPYING
CREDITS
Kbuild
Kconfig UPSTREAM: kbuild: ensure full rebuild when the compiler is updated 2020-09-24 10:02:38 +00:00
MAINTAINERS This is the 5.4.61 stable release 2020-08-26 11:11:38 +02:00
Makefile UPSTREAM: security: allow using Clang's zero initialization for stack variables 2020-09-08 15:12:44 +00:00
README
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.

  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 script/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 ...) 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 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 ...) 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 c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
        [ 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
    • 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)