Alex reports that his system fails to suspend using 5.12-rc1, with the
following dump:
[ 240.650300] PM: suspend entry (deep)
[ 240.650748] Filesystems sync: 0.000 seconds
[ 240.725605] Freezing user space processes ...
[ 260.739483] Freezing of tasks failed after 20.013 seconds (3 tasks refusing to freeze, wq_busy=0):
[ 260.739497] task:iou-mgr-446 state:S stack: 0 pid: 516 ppid: 439 flags:0x00004224
[ 260.739504] Call Trace:
[ 260.739507] ? sysvec_apic_timer_interrupt+0xb/0x81
[ 260.739515] ? pick_next_task_fair+0x197/0x1cde
[ 260.739519] ? sysvec_reschedule_ipi+0x2f/0x6a
[ 260.739522] ? asm_sysvec_reschedule_ipi+0x12/0x20
[ 260.739525] ? __schedule+0x57/0x6d6
[ 260.739529] ? del_timer_sync+0xb9/0x115
[ 260.739533] ? schedule+0x63/0xd5
[ 260.739536] ? schedule_timeout+0x219/0x356
[ 260.739540] ? __next_timer_interrupt+0xf1/0xf1
[ 260.739544] ? io_wq_manager+0x73/0xb1
[ 260.739549] ? io_wq_create+0x262/0x262
[ 260.739553] ? ret_from_fork+0x22/0x30
[ 260.739557] task:iou-mgr-517 state:S stack: 0 pid: 522 ppid: 439 flags:0x00004224
[ 260.739561] Call Trace:
[ 260.739563] ? sysvec_apic_timer_interrupt+0xb/0x81
[ 260.739566] ? pick_next_task_fair+0x16f/0x1cde
[ 260.739569] ? sysvec_apic_timer_interrupt+0xb/0x81
[ 260.739571] ? asm_sysvec_apic_timer_interrupt+0x12/0x20
[ 260.739574] ? __schedule+0x5b7/0x6d6
[ 260.739578] ? del_timer_sync+0x70/0x115
[ 260.739581] ? schedule_timeout+0x211/0x356
[ 260.739585] ? __next_timer_interrupt+0xf1/0xf1
[ 260.739588] ? io_wq_check_workers+0x15/0x11f
[ 260.739592] ? io_wq_manager+0x69/0xb1
[ 260.739596] ? io_wq_create+0x262/0x262
[ 260.739600] ? ret_from_fork+0x22/0x30
[ 260.739603] task:iou-wrk-517 state:S stack: 0 pid: 523 ppid: 439 flags:0x00004224
[ 260.739607] Call Trace:
[ 260.739609] ? __schedule+0x5b7/0x6d6
[ 260.739614] ? schedule+0x63/0xd5
[ 260.739617] ? schedule_timeout+0x219/0x356
[ 260.739621] ? __next_timer_interrupt+0xf1/0xf1
[ 260.739624] ? task_thread.isra.0+0x148/0x3af
[ 260.739628] ? task_thread_unbound+0xa/0xa
[ 260.739632] ? task_thread_bound+0x7/0x7
[ 260.739636] ? ret_from_fork+0x22/0x30
[ 260.739647] OOM killer enabled.
[ 260.739648] Restarting tasks ... done.
[ 260.740077] PM: suspend exit
Play nice and ensure that any thread we create will call try_to_freeze()
at an opportune time so that memory suspend can proceed. For the io-wq
worker threads, mark them as PF_NOFREEZE. They could potentially be
blocked for a long time.
Reported-by: Alex Xu (Hello71) <alex_y_xu@xxxxxxxx>
Tested-by: Alex Xu (Hello71) <alex_y_xu@xxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
fs/io-wq.c | 3 +++
fs/io_uring.c | 5 ++---
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 1fdb2b621b51..a44bd22c045e 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -16,6 +16,7 @@
#include <linux/rculist_nulls.h>
#include <linux/cpu.h>
#include <linux/tracehook.h>
+#include <linux/freezer.h>
#include "../kernel/sched/sched.h"
#include "io-wq.h"
@@ -263,6 +264,7 @@ static void io_wqe_dec_running(struct io_worker *worker)
static void io_worker_start(struct io_worker *worker)
{
+ current->flags |= PF_NOFREEZE;
worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
io_wqe_inc_running(worker);
complete(&worker->started);
@@ -731,6 +733,7 @@ static int io_wq_manager(void *data)
set_current_state(TASK_INTERRUPTIBLE);
io_wq_check_workers(wq);
schedule_timeout(HZ);
+ try_to_freeze();
if (fatal_signal_pending(current))
set_bit(IO_WQ_BIT_EXIT, &wq->state);
} while (!test_bit(IO_WQ_BIT_EXIT, &wq->state));
diff --git a/fs/io_uring.c b/fs/io_uring.c
index d9161b181a21..7cf8d4a99d91 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -74,13 +74,11 @@
#include <linux/fsnotify.h>
#include <linux/fadvise.h>
#include <linux/eventpoll.h>
-#include <linux/fs_struct.h>
#include <linux/splice.h>
#include <linux/task_work.h>
#include <linux/pagemap.h>
#include <linux/io_uring.h>
-#include <linux/blk-cgroup.h>
-#include <linux/audit.h>
+#include <linux/freezer.h>
#define CREATE_TRACE_POINTS
#include <trace/events/io_uring.h>
@@ -6736,6 +6734,7 @@ static int io_sq_thread(void *data)
io_ring_set_wakeup_flag(ctx);
schedule();
+ try_to_freeze();
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
io_ring_clear_wakeup_flag(ctx);
}
--
2.30.1
