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-rw-r--r--broken-sleep-5.4.48+.patch152
1 files changed, 0 insertions, 152 deletions
diff --git a/broken-sleep-5.4.48+.patch b/broken-sleep-5.4.48+.patch
deleted file mode 100644
index e922de302b1..00000000000
--- a/broken-sleep-5.4.48+.patch
+++ /dev/null
@@ -1,152 +0,0 @@
-From f7757368e0f0b3e108088ca7b5b8abda6faa7ebc Mon Sep 17 00:00:00 2001
-From: Peter Zijlstra <peterz@infradead.org>
-Date: Wed, 1 Apr 2020 17:40:33 -0400
-Subject: sched/core: Fix illegal RCU from offline CPUs
-
-[ Upstream commit bf2c59fce4074e55d622089b34be3a6bc95484fb ]
-
-In the CPU-offline process, it calls mmdrop() after idle entry and the
-subsequent call to cpuhp_report_idle_dead(). Once execution passes the
-call to rcu_report_dead(), RCU is ignoring the CPU, which results in
-lockdep complaining when mmdrop() uses RCU from either memcg or
-debugobjects below.
-
-Fix it by cleaning up the active_mm state from BP instead. Every arch
-which has CONFIG_HOTPLUG_CPU should have already called idle_task_exit()
-from AP. The only exception is parisc because it switches them to
-&init_mm unconditionally (see smp_boot_one_cpu() and smp_cpu_init()),
-but the patch will still work there because it calls mmgrab(&init_mm) in
-smp_cpu_init() and then should call mmdrop(&init_mm) in finish_cpu().
-
- WARNING: suspicious RCU usage
- -----------------------------
- kernel/workqueue.c:710 RCU or wq_pool_mutex should be held!
-
- other info that might help us debug this:
-
- RCU used illegally from offline CPU!
- Call Trace:
- dump_stack+0xf4/0x164 (unreliable)
- lockdep_rcu_suspicious+0x140/0x164
- get_work_pool+0x110/0x150
- __queue_work+0x1bc/0xca0
- queue_work_on+0x114/0x120
- css_release+0x9c/0xc0
- percpu_ref_put_many+0x204/0x230
- free_pcp_prepare+0x264/0x570
- free_unref_page+0x38/0xf0
- __mmdrop+0x21c/0x2c0
- idle_task_exit+0x170/0x1b0
- pnv_smp_cpu_kill_self+0x38/0x2e0
- cpu_die+0x48/0x64
- arch_cpu_idle_dead+0x30/0x50
- do_idle+0x2f4/0x470
- cpu_startup_entry+0x38/0x40
- start_secondary+0x7a8/0xa80
- start_secondary_resume+0x10/0x14
-
-Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
-Signed-off-by: Qian Cai <cai@lca.pw>
-Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
-Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
-Link: https://lkml.kernel.org/r/20200401214033.8448-1-cai@lca.pw
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- arch/powerpc/platforms/powernv/smp.c | 1 -
- include/linux/sched/mm.h | 2 ++
- kernel/cpu.c | 18 +++++++++++++++++-
- kernel/sched/core.c | 5 +++--
- 4 files changed, 22 insertions(+), 4 deletions(-)
-
-diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
-index 13e251699346..b2ba3e95bda7 100644
---- a/arch/powerpc/platforms/powernv/smp.c
-+++ b/arch/powerpc/platforms/powernv/smp.c
-@@ -167,7 +167,6 @@ static void pnv_smp_cpu_kill_self(void)
- /* Standard hot unplug procedure */
-
- idle_task_exit();
-- current->active_mm = NULL; /* for sanity */
- cpu = smp_processor_id();
- DBG("CPU%d offline\n", cpu);
- generic_set_cpu_dead(cpu);
-diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
-index c49257a3b510..a132d875d351 100644
---- a/include/linux/sched/mm.h
-+++ b/include/linux/sched/mm.h
-@@ -49,6 +49,8 @@ static inline void mmdrop(struct mm_struct *mm)
- __mmdrop(mm);
- }
-
-+void mmdrop(struct mm_struct *mm);
-+
- /*
- * This has to be called after a get_task_mm()/mmget_not_zero()
- * followed by taking the mmap_sem for writing before modifying the
-diff --git a/kernel/cpu.c b/kernel/cpu.c
-index d7890c1285bf..7527825ac7da 100644
---- a/kernel/cpu.c
-+++ b/kernel/cpu.c
-@@ -3,6 +3,7 @@
- *
- * This code is licenced under the GPL.
- */
-+#include <linux/sched/mm.h>
- #include <linux/proc_fs.h>
- #include <linux/smp.h>
- #include <linux/init.h>
-@@ -564,6 +565,21 @@ static int bringup_cpu(unsigned int cpu)
- return bringup_wait_for_ap(cpu);
- }
-
-+static int finish_cpu(unsigned int cpu)
-+{
-+ struct task_struct *idle = idle_thread_get(cpu);
-+ struct mm_struct *mm = idle->active_mm;
-+
-+ /*
-+ * idle_task_exit() will have switched to &init_mm, now
-+ * clean up any remaining active_mm state.
-+ */
-+ if (mm != &init_mm)
-+ idle->active_mm = &init_mm;
-+ mmdrop(mm);
-+ return 0;
-+}
-+
- /*
- * Hotplug state machine related functions
- */
-@@ -1434,7 +1450,7 @@ static struct cpuhp_step cpuhp_hp_states[] = {
- [CPUHP_BRINGUP_CPU] = {
- .name = "cpu:bringup",
- .startup.single = bringup_cpu,
-- .teardown.single = NULL,
-+ .teardown.single = finish_cpu,
- .cant_stop = true,
- },
- /* Final state before CPU kills itself */
-diff --git a/kernel/sched/core.c b/kernel/sched/core.c
-index e99d326fa569..4874e1468279 100644
---- a/kernel/sched/core.c
-+++ b/kernel/sched/core.c
-@@ -6177,13 +6177,14 @@ void idle_task_exit(void)
- struct mm_struct *mm = current->active_mm;
-
- BUG_ON(cpu_online(smp_processor_id()));
-+ BUG_ON(current != this_rq()->idle);
-
- if (mm != &init_mm) {
- switch_mm(mm, &init_mm, current);
-- current->active_mm = &init_mm;
- finish_arch_post_lock_switch();
- }
-- mmdrop(mm);
-+
-+ /* finish_cpu(), as ran on the BP, will clean up the active_mm state */
- }
-
- /*
---
-cgit 1.2.3-1.el7
-