android13-5.15 March 2026 release 2 Artifacts: https://ci.android.com/builds/submitted/15063902/kernel_aarch64/latest
ANDROID: sched: Fix deadlock in sched_blocked_reason tracepoint
The sched_blocked_reason tracepoint introduced in android common
in commit 1f52bb8bfd30 ("ANDROID: trace: sched: add sched
blocked tracepoint which dumps out context of sleep.") calls
get_wchan().
Unfortunately, get_wchan() was reworked upstream in commit
42a20f86dc19 ("sched: Add wrapper for get_wchan() to keep task
blocked"), such that it now takes the task pi_lock.
This causes a deadlock, as we are already holding the pi_lock
in try_to_wakeup() when we call trace_sched_blocked_reason().
This patch reworks the tracepoint so that it calls __get_wchan()
which does not take the lock, avoiding the deadlock.
Bug: 484195841
Bug: 490994511
Bug: 494491818
Test: Manual: run perfetto with ftrace_events: "sched/sched_blocked_reason" in the config
Fixes: 1f52bb8bfd30 ("ANDROID: trace: sched: add sched blocked tracepoint which dumps out context of sleep.")
Signed-off-by: John Stultz <jstultz@google.com>
Change-Id: I94e4251418d709a7b9292b3301c6cadd8fa3fb23
(cherry picked from commit 017f3c6586bef8795adb9f3c9385daef77a2e3fe)
(cherry picked from commit 6f769272d819779ff6d52e3f3244199e3d7a8dc4)
(cherry picked from commit f5526d1116e5c08b1599cddd5b90192d06bade99)
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.
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.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.
scripts/checkpatch.plUPSTREAM:, BACKPORT:, FROMGIT:, FROMLIST:, or ANDROID:.Change-Id: tag (see https://gerrit-review.googlesource.com/Documentation/user-changeid.html)Bug: tag.Signed-off-by: tag by the author and the submitterAdditional requirements are listed below based on patch type
UPSTREAM:, BACKPORT:UPSTREAM:.(cherry picked from commit ...) line 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>
BACKPORT: instead of UPSTREAM:.UPSTREAM:(cherry picked from commit ...) line 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>
FROMGIT:, FROMLIST:,FROMGIT:(cherry picked from commit <sha1> <repo> <branch>). This must be a stable maintainer branch (not rebased, so don't use linux-next for example).BACKPORT: FROMGIT: 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>
FROMLIST:Link: tag with a link to the submittal on lore.kernel.orgBug: tag with the Android bug (required for patches not accepted into a maintainer tree)BACKPORT: FROMLIST: 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>
ANDROID:ANDROID:Fixes: tag that cites the patch with the bug 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>
ANDROID:Bug: tag with the Android bug (required for android-specific features)