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android/kernel/common.git/refs/heads/android14-6.1-2026-06
commit
931d39a82dd574743d3d2ce9cbd407d46eb3487c
[log]
author
Davidlohr Bueso <dave@stgolabs.net>
Tue Jun 16 21:47:39 2026 -0400
committer
Lee Jones <joneslee@google.com>
Thu Jul 23 10:37:18 2026 +0100
tree
5a88bfad7445d6c7c74c64e01a4ff7dce5b3dce6
parent
33133021a324873a44ecdf1477694f0ca94d157e [diff]
UPSTREAM: locking/rtmutex: Skip remove_waiter() when waiter is not enqueued

[ Upstream commit 40a25d59e85b3c8709ac2424d44f65610467871e ]

syzbot triggered the following splat in remove_waiter() via
FUTEX_CMP_REQUEUE_PI:

  KASAN: null-ptr-deref in range [0x0000000000000a88-0x0000000000000a8f]
   class_raw_spinlock_constructor
   remove_waiter+0x159/0x1200 kernel/locking/rtmutex.c:1561
   rt_mutex_start_proxy_lock+0x103/0x120
   futex_requeue+0x10e4/0x20d0
   __x64_sys_futex+0x34f/0x4d0

task_blocks_on_rt_mutex() does not arm the waiter upon deadlock detection,
leaving waiter->task nil, where 3bfdc63936dd ("rtmutex: Use waiter::task instead
of current in remove_waiter()") made this fatal.

Furthermore, rt_mutex_start_proxy_lock() should not be calling into remove_waiter()
upon a successfully grabbing the rtmutex. 1a1fb985f2e2 ("futex: Handle early deadlock
return correctly"), moved the remove_waiter() out of __rt_mutex_start_proxy_lock()
(where 'ret' was only ever 0 or < 0) into the wrapper. Tighten this check to
account for try_to_take_rt_mutex().

Bug: 496407345
Fixes: 3bfdc63936dd ("rtmutex: Use waiter::task instead of current in remove_waiter()")
Reported-by: syzbot+78147abe6c524f183ee9@syzkaller.appspotmail.com
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Closes: https://lore.kernel.org/all/69f114ac.050a0220.ac8b.0003.GAE@google.com/
Link: https://patch.msgid.link/20260507112913.1019537-1-dave@stgolabs.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 6707d7e0b71748cb3cd95bad81dae5fe1b3c8f48)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: I1b3b0317abcc037c46e06a78f3c302d50bd3fc72
2 files changed
tree: 5a88bfad7445d6c7c74c64e01a4ff7dce5b3dce6
  1. android/
  2. arch/
  3. bazel/
  4. block/
  5. certs/
  6. crypto/
  7. Documentation/
  8. drivers/
  9. fs/
  10. include/
  11. init/
  12. io_uring/
  13. ipc/
  14. kernel/
  15. lib/
  16. LICENSES/
  17. mm/
  18. net/
  19. rust/
  20. samples/
  21. scripts/
  22. security/
  23. sound/
  24. tools/
  25. usr/
  26. virt/
  27. .clang-format
  28. .cocciconfig
  29. .get_maintainer.ignore
  30. .gitattributes
  31. .gitignore
  32. .mailmap
  33. .rustfmt.toml
  34. BUILD.bazel
  35. build.config.aarch64
  36. build.config.allmodconfig
  37. build.config.allmodconfig.aarch64
  38. build.config.allmodconfig.arm
  39. build.config.allmodconfig.x86_64
  40. build.config.amlogic
  41. build.config.arm
  42. build.config.common
  43. build.config.constants
  44. build.config.crashdump
  45. build.config.crashdump.aarch64
  46. build.config.crashdump.x86_64
  47. build.config.db845c
  48. build.config.gki
  49. build.config.gki-debug.aarch64
  50. build.config.gki-debug.x86_64
  51. build.config.gki.aarch64
  52. build.config.gki.aarch64.fips140
  53. build.config.gki.riscv64
  54. build.config.gki.x86_64
  55. build.config.gki_kasan
  56. build.config.gki_kasan.aarch64
  57. build.config.gki_kasan.x86_64
  58. build.config.gki_kprobes
  59. build.config.gki_kprobes.aarch64
  60. build.config.gki_kprobes.x86_64
  61. build.config.khwasan
  62. build.config.microdroid
  63. build.config.microdroid.aarch64
  64. build.config.microdroid.x86_64
  65. build.config.riscv64
  66. build.config.rockchip
  67. build.config.rockpi4
  68. build.config.wonder
  69. build.config.x86_64
  70. COPYING
  71. CREDITS
  72. Kbuild
  73. Kconfig
  74. Kconfig.ext
  75. MAINTAINERS
  76. Makefile
  77. modules.bzl
  78. OWNERS
  79. README
  80. 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)