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Eric W. Biederman b25b8c55ba UPSTREAM: coredump: Limit what can interrupt coredumps
[ Upstream commit 06af8679449d4ed282df13191fc52d5ba28ec536 ]

Olivier Langlois has been struggling with coredumps being incompletely written in
processes using io_uring.

Olivier Langlois <olivier@trillion01.com> writes:
> io_uring is a big user of task_work and any event that io_uring made a
> task waiting for that occurs during the core dump generation will
> generate a TIF_NOTIFY_SIGNAL.
>
> Here are the detailed steps of the problem:
> 1. io_uring calls vfs_poll() to install a task to a file wait queue
>    with io_async_wake() as the wakeup function cb from io_arm_poll_handler()
> 2. wakeup function ends up calling task_work_add() with TWA_SIGNAL
> 3. task_work_add() sets the TIF_NOTIFY_SIGNAL bit by calling
>    set_notify_signal()

The coredump code deliberately supports being interrupted by SIGKILL,
and depends upon prepare_signal to filter out all other signals.   Now
that signal_pending includes wake ups for TIF_NOTIFY_SIGNAL this hack
in dump_emitted by the coredump code no longer works.

Make the coredump code more robust by explicitly testing for all of
the wakeup conditions the coredump code supports.  This prevents
new wakeup conditions from breaking the coredump code, as well
as fixing the current issue.

The filesystem code that the coredump code uses already limits
itself to only aborting on fatal_signal_pending.  So it should
not develop surprising wake-up reasons either.

v2: Don't remove the now unnecessary code in prepare_signal.

Cc: stable@vger.kernel.org
Fixes: 12db8b690010 ("entry: Add support for TIF_NOTIFY_SIGNAL")
Reported-by: Olivier Langlois <olivier@trillion01.com>
Change-Id: I84870bf0a620a97af50d9b495dd225f9ee2b66b8
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 4b4d2c79921a8327e9e853dc93c06b27edb3a859)
Bug: 268174392
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2023-02-07 13:38:13 +00:00
Documentation BACKPORT: f2fs: introduce memory mode 2023-02-03 18:44:20 +00:00
LICENSES
android ANDROID: GKI: Add Tuxera symbol list 2023-01-31 17:17:17 +00:00
arch UPSTREAM: alpha: fix TIF_NOTIFY_SIGNAL handling 2023-02-07 13:38:13 +00:00
block Merge tag 'android12-5.10.160_r00' into android12-5.10 2023-01-21 12:06:54 +00:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:13:17 +02:00
crypto Merge tag 'android12-5.10.160_r00' into android12-5.10 2023-01-21 12:06:54 +00:00
drivers UPSTREAM: file: Rename __close_fd_get_file close_fd_get_file 2023-02-07 13:38:09 +00:00
fs UPSTREAM: coredump: Limit what can interrupt coredumps 2023-02-07 13:38:13 +00:00
include UPSTREAM: kernel: remove checking for TIF_NOTIFY_SIGNAL 2023-02-07 13:38:13 +00:00
init Merge tag 'android12-5.10.160_r00' into android12-5.10 2023-01-21 12:06:54 +00:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:24:00 +01:00
kernel UPSTREAM: kernel: remove checking for TIF_NOTIFY_SIGNAL 2023-02-07 13:38:13 +00:00
lib UPSTREAM: iov_iter: add helper to save iov_iter state 2023-02-07 13:38:07 +00:00
mm ANDROID: mm: page_pinner: ensure do_div() arguments matches with respect to type 2023-01-26 11:34:37 +00:00
net UPSTREAM: net: add accept helper not installing fd 2023-02-07 13:38:09 +00:00
samples ANDROID: fips140: add dump_jitterentropy command to fips140_lab_util 2023-01-06 19:08:16 +00:00
scripts Merge tag 'android12-5.10.160_r00' into android12-5.10 2023-01-21 12:06:54 +00:00
security This is the 5.10.154 stable release 2022-11-29 23:38:14 +00:00
sound UPSTREAM: ALSA: pcm: Move rwsem lock inside snd_ctl_elem_read to prevent UAF 2023-01-26 11:51:51 +00:00
tools UPSTREAM: tools headers UAPI: Sync openat2.h with the kernel sources 2023-02-07 13:38:08 +00:00
usr FROMLIST: kbuild: Add environment variables for userprogs flags 2022-05-10 16:09:36 +00:00
virt kvm: Add support for arch compat vm ioctls 2022-10-30 09:41:15 +01:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Merge 5.10.38 into android12-5.10 2021-05-20 15:35:25 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild
Kconfig
MAINTAINERS This is the 5.10.128 stable release 2022-07-28 16:54:11 +02:00
Makefile Merge tag 'android12-5.10.160_r00' into android12-5.10 2023-01-21 12:06:54 +00:00
OWNERS ANDROID: Use authoritative Dr. No list from android-mainline 2021-07-22 15:25:25 +00:00
README
README.md
build.config.aarch64 ANDROID: arm64: enable compat vdso 2021-05-13 09:14:25 -07:00
build.config.allmodconfig ANDROID: Revert "ANDROID: allmodconfig: disable WERROR" 2023-01-26 11:34:37 +00:00
build.config.allmodconfig.aarch64
build.config.allmodconfig.arm
build.config.allmodconfig.x86_64
build.config.amlogic ANDROID: GKI: amlogic: add DTB overlays 2021-02-12 10:08:04 +01:00
build.config.arm ANDROID: enable LLVM_IAS=1 for clang's integrated assembler for arm 2021-03-24 09:21:58 -07:00
build.config.common ANDROID: fix KCFLAGS override by __ANDROID_COMMON_KERNEL__ 2022-04-29 20:20:21 +00:00
build.config.db845c ANDROID: db845c: Use FRAGMENT_CONFIG 2021-02-10 06:08:17 +00:00
build.config.gki
build.config.gki-debug.aarch64
build.config.gki-debug.x86_64
build.config.gki.aarch64 ANDROID: GKI: Add Tuxera symbol list 2023-01-31 17:17:17 +00:00
build.config.gki.aarch64.fips140 ANDROID: ABI: add new symbols required by fips140.ko 2021-10-29 14:32:49 -07:00
build.config.gki.aarch64.fips140_eval_testing ANDROID: fips140: support "evaluation testing" builds via build.sh 2021-11-30 17:55:05 +00:00
build.config.gki.x86_64
build.config.gki_kasan ANDROID: build.config: Disable LTO for KASAN and Kprobes builds 2021-03-08 00:31:49 +00:00
build.config.gki_kasan.aarch64
build.config.gki_kasan.x86_64
build.config.gki_kprobes ANDROID: build.config: Disable LTO for KASAN and Kprobes builds 2021-03-08 00:31:49 +00:00
build.config.gki_kprobes.aarch64 ANDROID: Adding kprobes build configs for Cuttlefish 2021-03-03 02:03:02 +00:00
build.config.gki_kprobes.x86_64 ANDROID: Adding kprobes build configs for Cuttlefish 2021-03-03 02:03:02 +00:00
build.config.hikey960 ANDROID: Add hikey960 build infrastructure file 2021-02-18 23:59:34 +00:00
build.config.khwasan ANDROID: Add a build config fragment for KHWASan. 2021-04-06 10:01:56 +00:00
build.config.rockchip ANDROID: GKI: rockchip: update fragment file 2022-08-19 19:27:37 +00:00
build.config.x86_64 ANDROID: build.config: Add vmlinux.symvers and modules.builtin to DIST_DIR 2021-04-15 10:24:17 +01:00

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 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 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)