mirror of
https://github.com/hardkernel/linux.git
synced 2026-06-05 02:21:52 +09:00
e30317e116
Symbolization techniques use address ranges as reported in /proc/*/maps
to infer the corresponding /proc/*/map_files/ entry.
Per Daniel, this is done because the path in /proc/*/maps is problematic
for at least two reasons:
1. The file could have been deleted from the file system (this is
indicated with the (deleted) suffix), meaning that you can't
actually open it through the "regular" file system. However,
while the mapping is alive, the kernel keeps the inode accessible
via the corresponding /proc/*/map_files entry, allowing for
access after all.
2. It makes dealing with changed root and file system namespaces
much more painful. The /proc/*/maps path is relative, and so now
you need to concatenate paths etc. Accessing file through
/proc/*/map_files just works (assuming necessary permissions), as
the kernel redirects the request to the proper inode,
irrespective of how it is exposed through the non-proc
filesystem.
Android extends ELF padding regions to be contiguously mapped in memory
to mitigate increase in unreclaimable VMA slab memory usage.
Commit 8c2a805a857914324b077708b45c31c2f20d02da [1] emulates the padding
region of such extended mappings to be outputted as PROT_NONE
[page size compat] entries from /proc/*/[s]maps. This breaks the use
case of /proc/*/maps_files/, as the ranges in /proc/*/map_files/ are
the true ranges of the actual underlying VMA layout; while those in
/proc/*/[s]maps are the emulated (shortened) ranges.
Remove the padding (extended) ranges from /proc/*/maps_files entries.
====== Example Output ======
=== maps ===
❯ adb shell cat /proc/1/maps | grep -A1 libdl_android.so | sed '$d'
7f76663df000-7f76663e0000 r--p 00000000 fe:09 1911 /system/lib64/bootstrap/libdl_android.so
7f76663e0000-7f76663e3000 ---p 00000000 00:00 0 [page size compat]
7f76663e3000-7f76663e4000 r-xp 00004000 fe:09 1911 /system/lib64/bootstrap/libdl_android.so
7f76663e4000-7f76663e7000 ---p 00000000 00:00 0 [page size compat]
7f76663e7000-7f76663e8000 r--p 00008000 fe:09 1911 /system/lib64/bootstrap/libdl_android.s
=== map_files - Before patch ===
❯ adb shell ls /proc/1/map_files | grep -A2 7f76663df000
7f76663df000-7f76663e3000
7f76663e3000-7f76663e7000
7f76663e7000-7f76663e8000
=== map_files - After patch ===
❯ adb shell ls /proc/1/map_files | grep -A2 7f76663df000
7f76663df000-7f76663e0000
7f76663e3000-7f76663e4000
7f76663e7000-7f76663e8000
[1] 8c2a805a85
Bug: 418042003
Change-Id: I0f6d703715a0e709fa1d4bd52241b5fd913dd55e
Reported-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
How do I submit patches to Android Common Kernels
-
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.
- Do not send patches upstream that contain only symbol exports. To be considered for upstream Linux,
additions of
-
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:, orANDROID:. - 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
- tag the patch subject with
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 ofUPSTREAM:.- use the same tags as
UPSTREAM: - add comments about the changes under the
(cherry picked from commit ...)line - Example:
- use the same tags as
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 uselinux-nextfor example). - if changes were required, use
BACKPORT: FROMGIT: - Example:
- if the commit message in the maintainer tree is
- tag the patch subject with
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:
- tag the patch subject with
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:
- tag the patch subject with
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)
- tag the patch subject with