Google Git
Sign in
android / kernel / common.git / 59d826468078a51b683e550b9ea9f2a1f2dce870
commit59d826468078a51b683e550b9ea9f2a1f2dce870[log] [tgz]
authorJaegeuk Kim <jaegeuk@google.com>Wed Oct 27 09:07:09 2021 -0700
committerJaegeuk Kim <jaegeuk@google.com>Wed Oct 27 21:27:48 2021 +0000
tree410ce88ffb528d10ecdca22aa8a92dea24bcea65
parentdc8c919ca6165de1aad86dec43f17d6ec5fb46ce [diff]
ANDROID: f2fs: fix potential deadlock by android ftrace

sb_internal#2 --> &s->s_dquot.dqio_sem --> fs_reclaim

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(fs_reclaim);
                                lock(&s->s_dquot.dqio_sem);
                                lock(fs_reclaim);
   lock(sb_internal#2);

 *** DEADLOCK ***

 3 locks held by kswapd0/133:
  #0: ffffffda597c93a8 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x4/0x50
  #1: ffffffda597bc890 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0xa0/0x19c
  #2: ffffff80d5fb90e0 (&type->s_umount_key#50){.+.+}-{3:3}, at: super_cache_scan+0x40/0x1dc

stack backtrace:
 CPU: 7 PID: 133 Comm: kswapd0 Tainted: G        W  O      5.10.43-android12-9-g4665ec64f3df #1
 Hardware name: MT6879(ENG) (DT)
 Call trace:
  dump_backtrace.cfi_jt+0x0/0x8
  show_stack+0x1c/0x2c
  dump_stack_lvl+0xd8/0x16c
  print_circular_bug+0x2d4/0x2d8
  check_noncircular+0x190/0x1a4
  validate_chain+0xc54/0x2d34
  __lock_acquire+0x7e4/0xed4
  lock_acquire+0x114/0x394
  f2fs_evict_inode+0x1a0/0x8b8
  evict+0xd4/0x2f8
  iput+0x1c0/0x258
  dentry_unlink_inode+0x16c/0x1dc
  __dentry_kill+0x128/0x280
  shrink_dentry_list+0x6c/0x420
  prune_dcache_sb+0x5c/0x90
  super_cache_scan+0x13c/0x1dc
  do_shrink_slab+0x1e0/0x388
  shrink_slab+0xf4/0x19c
  shrink_node_memcgs+0x80/0x25c
  shrink_node+0x324/0x710
  balance_pgdat+0x3a8/0x6a8
  kswapd+0x484/0x594
  kthread+0x15c/0x1ac
  ret_from_fork+0x10/0x30

Bug: 201025620
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
Change-Id: Idaa303eb7c681a56ad5d4e1f6dddbda71f7fece4
1 file changed
tree: 410ce88ffb528d10ecdca22aa8a92dea24bcea65
  1. android/
  2. arch/
  3. block/
  4. certs/
  5. crypto/
  6. Documentation/
  7. drivers/
  8. fs/
  9. include/
  10. init/
  11. ipc/
  12. kernel/
  13. lib/
  14. LICENSES/
  15. mm/
  16. net/
  17. samples/
  18. scripts/
  19. security/
  20. sound/
  21. tools/
  22. usr/
  23. virt/
  24. .clang-format
  25. .cocciconfig
  26. .get_maintainer.ignore
  27. .gitattributes
  28. .gitignore
  29. .mailmap
  30. build.config.aarch64
  31. build.config.allmodconfig
  32. build.config.allmodconfig.aarch64
  33. build.config.allmodconfig.arm
  34. build.config.allmodconfig.x86_64
  35. build.config.arm
  36. build.config.common
  37. build.config.db845c
  38. build.config.gki
  39. build.config.gki-debug.aarch64
  40. build.config.gki-debug.x86_64
  41. build.config.gki.aarch64
  42. build.config.gki.x86_64
  43. build.config.gki_kasan
  44. build.config.gki_kasan.aarch64
  45. build.config.gki_kasan.x86_64
  46. build.config.gki_kprobes
  47. build.config.gki_kprobes.aarch64
  48. build.config.gki_kprobes.x86_64
  49. build.config.hikey960
  50. build.config.x86_64
  51. COPYING
  52. CREDITS
  53. Kbuild
  54. Kconfig
  55. MAINTAINERS
  56. Makefile
  57. OWNERS
  58. README
  59. 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.

  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)