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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:06:00 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:06:00 +0000
commitb15a952c52a6825376d3e7f6c1bf5c886c6d8b74 (patch)
tree1500f2f8f276908a36d8126cb632c0d6b1276764 /debian/patches-rt/0015-sched-lockdep-Annotate-pi_lock-recursion.patch
parentAdding upstream version 5.10.209. (diff)
downloadlinux-b15a952c52a6825376d3e7f6c1bf5c886c6d8b74.tar.xz
linux-b15a952c52a6825376d3e7f6c1bf5c886c6d8b74.zip
Adding debian version 5.10.209-2.debian/5.10.209-2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--debian/patches-rt/0015-sched-lockdep-Annotate-pi_lock-recursion.patch52
1 files changed, 52 insertions, 0 deletions
diff --git a/debian/patches-rt/0015-sched-lockdep-Annotate-pi_lock-recursion.patch b/debian/patches-rt/0015-sched-lockdep-Annotate-pi_lock-recursion.patch
new file mode 100644
index 000000000..05030516b
--- /dev/null
+++ b/debian/patches-rt/0015-sched-lockdep-Annotate-pi_lock-recursion.patch
@@ -0,0 +1,52 @@
+From c0e34a5ef4e854220a216e934ab90f04d4432bdd Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:12 +0200
+Subject: [PATCH 015/323] sched, lockdep: Annotate ->pi_lock recursion
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+There's a valid ->pi_lock recursion issue where the actual PI code
+tries to wake up the stop task. Make lockdep aware so it doesn't
+complain about this.
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/core.c | 15 +++++++++++++++
+ 1 file changed, 15 insertions(+)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 2517a003295b..abbf01f77a76 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -2670,6 +2670,7 @@ int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags)
+
+ void sched_set_stop_task(int cpu, struct task_struct *stop)
+ {
++ static struct lock_class_key stop_pi_lock;
+ struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
+ struct task_struct *old_stop = cpu_rq(cpu)->stop;
+
+@@ -2685,6 +2686,20 @@ void sched_set_stop_task(int cpu, struct task_struct *stop)
+ sched_setscheduler_nocheck(stop, SCHED_FIFO, &param);
+
+ stop->sched_class = &stop_sched_class;
++
++ /*
++ * The PI code calls rt_mutex_setprio() with ->pi_lock held to
++ * adjust the effective priority of a task. As a result,
++ * rt_mutex_setprio() can trigger (RT) balancing operations,
++ * which can then trigger wakeups of the stop thread to push
++ * around the current task.
++ *
++ * The stop task itself will never be part of the PI-chain, it
++ * never blocks, therefore that ->pi_lock recursion is safe.
++ * Tell lockdep about this by placing the stop->pi_lock in its
++ * own class.
++ */
++ lockdep_set_class(&stop->pi_lock, &stop_pi_lock);
+ }
+
+ cpu_rq(cpu)->stop = stop;
+--
+2.43.0
+