diff options
Diffstat (limited to 'debian/patches-rt/0293-sched-Fix-affine_move_task-self-concurrency.patch')
| -rw-r--r-- | debian/patches-rt/0293-sched-Fix-affine_move_task-self-concurrency.patch | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/debian/patches-rt/0293-sched-Fix-affine_move_task-self-concurrency.patch b/debian/patches-rt/0293-sched-Fix-affine_move_task-self-concurrency.patch new file mode 100644 index 000000000..4a906f7cb --- /dev/null +++ b/debian/patches-rt/0293-sched-Fix-affine_move_task-self-concurrency.patch @@ -0,0 +1,96 @@ +From e9faaf024fdd553b55aaed31855385da7e9d505a Mon Sep 17 00:00:00 2001 +From: Peter Zijlstra <peterz@infradead.org> +Date: Tue, 8 Jun 2021 00:37:34 -0400 +Subject: [PATCH 293/323] sched: Fix affine_move_task() self-concurrency +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz + +commit 9e81889c7648d48dd5fe13f41cbc99f3c362484a upstream. + +Consider: + + sched_setaffinity(p, X); sched_setaffinity(p, Y); + +Then the first will install p->migration_pending = &my_pending; and +issue stop_one_cpu_nowait(pending); and the second one will read +p->migration_pending and _also_ issue: stop_one_cpu_nowait(pending), +the _SAME_ @pending. + +This causes stopper list corruption. + +Add set_affinity_pending::stop_pending, to indicate if a stopper is in +progress. + +Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()") +Cc: stable@kernel.org +Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> +Signed-off-by: Ingo Molnar <mingo@kernel.org> +Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> +Link: https://lkml.kernel.org/r/20210224131355.649146419@infradead.org +Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> +Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> +--- + kernel/sched/core.c | 15 ++++++++++++--- + 1 file changed, 12 insertions(+), 3 deletions(-) + +diff --git a/kernel/sched/core.c b/kernel/sched/core.c +index e28fb33afa95..76fa3daf1f60 100644 +--- a/kernel/sched/core.c ++++ b/kernel/sched/core.c +@@ -1916,6 +1916,7 @@ struct migration_arg { + + struct set_affinity_pending { + refcount_t refs; ++ unsigned int stop_pending; + struct completion done; + struct cpu_stop_work stop_work; + struct migration_arg arg; +@@ -2034,12 +2035,15 @@ static int migration_cpu_stop(void *data) + * determine is_migration_disabled() and so have to chase after + * it. + */ ++ WARN_ON_ONCE(!pending->stop_pending); + task_rq_unlock(rq, p, &rf); + stop_one_cpu_nowait(task_cpu(p), migration_cpu_stop, + &pending->arg, &pending->stop_work); + return 0; + } + out: ++ if (pending) ++ pending->stop_pending = false; + task_rq_unlock(rq, p, &rf); + + if (complete) +@@ -2235,7 +2239,7 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag + int dest_cpu, unsigned int flags) + { + struct set_affinity_pending my_pending = { }, *pending = NULL; +- bool complete = false; ++ bool stop_pending, complete = false; + + /* Can the task run on the task's current CPU? If so, we're done */ + if (cpumask_test_cpu(task_cpu(p), &p->cpus_mask)) { +@@ -2308,14 +2312,19 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag + * anything else we cannot do is_migration_disabled(), punt + * and have the stopper function handle it all race-free. + */ ++ stop_pending = pending->stop_pending; ++ if (!stop_pending) ++ pending->stop_pending = true; + + refcount_inc(&pending->refs); /* pending->{arg,stop_work} */ + if (flags & SCA_MIGRATE_ENABLE) + p->migration_flags &= ~MDF_PUSH; + task_rq_unlock(rq, p, rf); + +- stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop, +- &pending->arg, &pending->stop_work); ++ if (!stop_pending) { ++ stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop, ++ &pending->arg, &pending->stop_work); ++ } + + if (flags & SCA_MIGRATE_ENABLE) + return 0; +-- +2.43.0 + |