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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0314-sched-migrate_enable-Busy-loop-until-the-migration-r.patch | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/debian/patches-rt/0314-sched-migrate_enable-Busy-loop-until-the-migration-r.patch b/debian/patches-rt/0314-sched-migrate_enable-Busy-loop-until-the-migration-r.patch new file mode 100644 index 000000000..d51c9b637 --- /dev/null +++ b/debian/patches-rt/0314-sched-migrate_enable-Busy-loop-until-the-migration-r.patch @@ -0,0 +1,57 @@ +From 090c26864ec17b496dea3397656b006550e31852 Mon Sep 17 00:00:00 2001 +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Thu, 12 Dec 2019 10:53:59 +0100 +Subject: [PATCH 314/347] sched: migrate_enable: Busy loop until the migration + request is completed +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +[ Upstream commit 140d7f54a5fff02898d2ca9802b39548bf7455f1 ] + +If user task changes the CPU affinity mask of a running task it will +dispatch migration request if the current CPU is no longer allowed. This +might happen shortly before a task enters a migrate_disable() section. +Upon leaving the migrate_disable() section, the task will notice that +the current CPU is no longer allowed and will will dispatch its own +migration request to move it off the current CPU. +While invoking __schedule() the first migration request will be +processed and the task returns on the "new" CPU with "arg.done = 0". Its +own migration request will be processed shortly after and will result in +memory corruption if the stack memory, designed for request, was used +otherwise in the meantime. + +Spin until the migration request has been processed if it was accepted. + +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> +--- + kernel/sched/core.c | 7 +++++-- + 1 file changed, 5 insertions(+), 2 deletions(-) + +diff --git a/kernel/sched/core.c b/kernel/sched/core.c +index 270adb525d93..d190d9e6b10f 100644 +--- a/kernel/sched/core.c ++++ b/kernel/sched/core.c +@@ -7323,7 +7323,7 @@ void migrate_enable(void) + + WARN_ON(smp_processor_id() != cpu); + if (!is_cpu_allowed(p, cpu)) { +- struct migration_arg arg = { p }; ++ struct migration_arg arg = { .task = p }; + struct cpu_stop_work work; + struct rq_flags rf; + +@@ -7336,7 +7336,10 @@ void migrate_enable(void) + &arg, &work); + tlb_migrate_finish(p->mm); + __schedule(true); +- WARN_ON_ONCE(!arg.done && !work.disabled); ++ if (!work.disabled) { ++ while (!arg.done) ++ cpu_relax(); ++ } + } + + out: +-- +2.36.1 + |