On 3/24/21 9:48 PM, Dong Kai wrote:
commit 15b2219facad ("kernel: freezer should treat PF_IO_WORKER like
PF_KTHREAD for freezing") is to fix the freezeing issue of IO threads
nit: s/freezeing/freezing
by making the freezer not send them fake signals.
Here live patching consistency model call klp_send_signals to wake up
all tasks by send fake signal to all non-kthread which only check the
PF_KTHREAD flag, so it still send signal to io threads which may lead to
freezeing issue of io threads.
Here we take the same fix action by treating PF_IO_WORKERS as PF_KTHREAD
within klp_send_signal function.
Signed-off-by: Dong Kai <dongkai11@xxxxxxxxxx>
---
note:
the io threads freeze issue links:
[1] https://lore.kernel.org/io-uring/YEgnIp43%2F6kFn8GL@xxxxxxxxxxxxxxx/
[2] https://lore.kernel.org/io-uring/d7350ce7-17dc-75d7-611b-27ebf2cb539b@xxxxxxxxx/
kernel/livepatch/transition.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index f6310f848f34..0e1c35c8f4b4 100644
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -358,7 +358,7 @@ static void klp_send_signals(void)
* Meanwhile the task could migrate itself and the action
* would be meaningless. It is not serious though.
*/
- if (task->flags & PF_KTHREAD) {
+ if (task->flags & (PF_KTHREAD | PF_IO_WORKER)) {
/*
* Wake up a kthread which sleeps interruptedly and
* still has not been migrated.
(PF_KTHREAD | PF_IO_WORKER) is open coded in soo many places maybe this
is a silly question, but...
If the livepatch code could use fake_signal_wake_up(), we could
consolidate the pattern in klp_send_signals() with the one in
freeze_task(). Then there would only one place for wake up / fake
signal logic.
I don't fully understand the differences in the freeze_task() version,
so I only pose this as a question and not v2 request.
As it is, this change seems logical to me, so:
Acked-by: Joe Lawrence <joe.lawrence@xxxxxxxxxx>
Thanks,
-- Joe
