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Filename Latest commit message Latest commit date
Saravana Kannan 5eee799bec UPSTREAM: driver core: Fix device_pm_lock() locking for device links
This commit fixes two issues:

1. The lockdep warning reported by Dong Aisheng <dongas86@gmail.com> [1].

It is a warning about a cycle (dpm_list_mtx --> kn->active#3 --> fw_lock)
that was introduced when device-link devices were added to expose device
link information in sysfs.

The patch that "introduced" this cycle can't be reverted because it's fixes
a real SRCU issue and also ensures that the device-link device is deleted
as soon as the device-link is deleted. This is important to avoid sysfs
name collisions if the device-link is create again immediately (this can
happen a lot with deferred probing).

2. Inconsistency in grabbing device_pm_lock() during device link deletion

Some device link deletion code paths grab device_pm_lock(), while others
don't.  The device_pm_lock() is grabbed during device_link_add() because it
checks if the supplier is in the dpm_list and also reorders the dpm_list.
However, when a device link is deleted, it does not do either of those and
therefore device_pm_lock() is not necessary. Dropping the device_pm_lock()
in all the device link deletion paths removes the inconsistency in locking.

Thanks to Stephen Boyd for helping me understand the lockdep splat.

Fixes: 843e600b8a2b ("driver core: Fix sleeping in invalid context during device link deletion")
[1] - https://lore.kernel.org/lkml/CAA+hA=S4eAreb7vo69LAXSk2t5=DEKNxHaiY1wSpk4xTp9urLg@mail.gmail.com/
Reported-by: Dong Aisheng <dongas86@gmail.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20200901184445.1736658-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 6b57b15abe11aa334ebf726e02c0deaf123ba040)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I714523d92bbfbad145df2794c481cd0b697d7d16
2020-11-14 16:20:48 +01:00
android ANDROID: GKI: update symbol list for exynosauto soc 2020-11-13 13:51:35 +00:00
arch ANDROID: arm64: smp: fix Lockdep warning: RCU used illegally from idle CPU. 2020-11-03 11:08:15 +08:00
block
certs
crypto
Documentation FROMLIST: power: supply: core: property to control reverse charge 2020-09-01 17:57:03 +00:00
drivers UPSTREAM: driver core: Fix device_pm_lock() locking for device links 2020-11-14 16:20:48 +01:00
fs UPSTREAM: fscrypt: restrict IV_INO_LBLK_32 to ino_bits <= 32 2020-11-14 16:20:41 +01:00
include ANDROID: fix kernelci build-break due to stop_ipi hook 2020-11-04 13:23:08 -08:00
init ANDROID: GKI: add fields required to enable CONFIG_TRANSPARENT_HUGEPAGE 2020-10-15 17:21:03 +02:00
ipc
kernel ANDROID: modules: cfi cleanup for module load failure 2020-11-06 10:09:05 +05:30
lib
LICENSES
mm UPSTREAM: mm/sl[uo]b: export __kmalloc_track(_node)_caller 2020-11-02 16:12:00 +00:00
net UPSTREAM: cfg80211: fix 6 GHz channel conversion 2020-11-14 16:09:30 +01:00
samples
scripts ANDROID: recordmcount: avoid STT_FILE as base for mcount offset relocation 2020-10-22 19:57:13 +00:00
security UPSTREAM: security: allow using Clang's zero initialization for stack variables 2020-09-08 15:12:44 +00:00
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
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
build.config.allmodconfig
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
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
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)