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android / kernel / common / 5dd8a05ba11a36d91c244d3e482a18a275e5d8ad
commit5dd8a05ba11a36d91c244d3e482a18a275e5d8ad[log] [tgz]
authorT.J. Mercier <[email protected]>Wed Nov 12 18:17:43 2025 -0800
committerTreehugger Robot <[email protected]>Mon Dec 01 11:45:05 2025 -0800
treea9f7b97334e3ad311b3cf4bdd186a37d5a8e9e8f
parenta92da54b770875ab263491bb8a70e602fe615ec8 [diff]
ANDROID: Don't use current pointer for per-process dmabuf accounting

If a child task is created with a partial sharing relationship with the
parent (e.g. CLONE_FILES && !CLONE_VM), AND that child task closes a
dmabuf in the partially shared (files/mm) structure, then the
dma_buf_unaccount_task operation will do nothing since tasks created
with partial sharing relationships do not have associated
task_dma_buf_info accounting structures associated with them. The dmabuf
will be closed, but the accounting information in the parent will still
have a record of the dead buffer. If nothing else happens, the result is
just incorrect accounting.

Later, if a fork is performed the accounting information is copied into
the child, and there a UAF occurs when we dereference the dead dmabuf in
the parent's accounting information in copy_dmabuf_info.

Fix this by tracking task_dma_buf_info in mm_struct and files_struct,
which will be used instead of the current task's task_dma_buf_info
pointer, even for unaccount operations via partial sharing.

Fixes: 060742b3d06d ("ANDROID: Track per-process dmabuf RSS")
Bug: 459757379
Bug: 461520624
Change-Id: Idaa4c39de396eb8261c018a816fb549356a2a5cc
Signed-off-by: T.J. Mercier <[email protected]>
8 files changed
tree: a9f7b97334e3ad311b3cf4bdd186a37d5a8e9e8f
  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. rust/
  19. samples/
  20. scripts/
  21. security/
  22. sound/
  23. tools/
  24. usr/
  25. virt/
  26. .clang-format
  27. .cocciconfig
  28. .get_maintainer.ignore
  29. .gitattributes
  30. .gitignore
  31. .mailmap
  32. .rustfmt.toml
  33. BUILD.bazel
  34. build.config.aarch64
  35. build.config.allmodconfig
  36. build.config.allmodconfig.aarch64
  37. build.config.allmodconfig.arm
  38. build.config.allmodconfig.x86_64
  39. build.config.amlogic
  40. build.config.arm
  41. build.config.common
  42. build.config.constants
  43. build.config.crashdump
  44. build.config.crashdump.aarch64
  45. build.config.crashdump.x86_64
  46. build.config.db845c
  47. build.config.gki
  48. build.config.gki-debug.aarch64
  49. build.config.gki-debug.x86_64
  50. build.config.gki.aarch64
  51. build.config.gki.aarch64.fips140
  52. build.config.gki.riscv64
  53. build.config.gki.x86_64
  54. build.config.gki_kasan
  55. build.config.gki_kasan.aarch64
  56. build.config.gki_kasan.x86_64
  57. build.config.gki_kprobes
  58. build.config.gki_kprobes.aarch64
  59. build.config.gki_kprobes.x86_64
  60. build.config.khwasan
  61. build.config.microdroid
  62. build.config.microdroid.aarch64
  63. build.config.microdroid.x86_64
  64. build.config.riscv64
  65. build.config.rockchip
  66. build.config.rockpi4
  67. build.config.x86_64
  68. COPYING
  69. CREDITS
  70. Kbuild
  71. Kconfig
  72. Kconfig.ext
  73. MAINTAINERS
  74. Makefile
  75. modules.bzl
  76. OWNERS
  77. README
  78. 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 [email protected]. 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 <[email protected]>
  • 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 <[email protected]>

        Bug: 135791357
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        (cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
        Signed-off-by: Joe Smith <[email protected]>
  • 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 <[email protected]>

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

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 <[email protected]>
  • 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 <[email protected]>

        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 <[email protected]>
  • 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 <[email protected]>

        Bug: 135791357
        Link: https://lore.kernel.org/lkml/[email protected]/
        Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
        Signed-off-by: Joe Smith <[email protected]>

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 <[email protected]>
  • 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)