[PATCH] net: pktgen: don't abuse current->state in pktgen_thread_worker()

Commit 1fbe4b46caca "net: pktgen: kill the Wait for kthread_stop
code in pktgen_thread_worker()" removed (in particular) the final
__set_current_state(TASK_RUNNING) and I didn't notice the previous
set_current_state(TASK_INTERRUPTIBLE). This triggers the warning
in __might_sleep() after return.

Afaics, we can simply remove both set_current_state()'s, and we
could do this a long ago right after ef87979c273a2 "pktgen: better
scheduler friendliness" which changed pktgen_thread_worker() to
use wait_event_interruptible_timeout().

Reported-by: Huang Ying <redacted>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 net/core/pktgen.c |    3 ---
 1 files changed, 0 insertions(+), 3 deletions(-)

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 8e0181a..6717684 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c

@@ -3432,8 +3432,6 @@ static int pktgen_thread_worker(void *arg)
 
 	set_freezable();
 
-	__set_current_state(TASK_RUNNING);
-
 	while (!kthread_should_stop()) {
 		pkt_dev = next_to_run(t);
 

@@ -3478,7 +3476,6 @@ static int pktgen_thread_worker(void *arg)
 
 		try_to_freeze();
 	}
-	set_current_state(TASK_INTERRUPTIBLE);
 
 	pr_debug("%s stopping all device\n", t->tsk->comm);
 	pktgen_stop(t);

-- 
1.5.5.1

On Tue, Aug 04, 2015 at 06:33:34PM +0200, Oleg Nesterov wrote:

Commit 1fbe4b46caca "net: pktgen: kill the Wait for kthread_stop
code in pktgen_thread_worker()" removed (in particular) the final
__set_current_state(TASK_RUNNING) and I didn't notice the previous
set_current_state(TASK_INTERRUPTIBLE). This triggers the warning
in __might_sleep() after return.

Afaics, we can simply remove both set_current_state()'s, and we
could do this a long ago right after ef87979c273a2 "pktgen: better
scheduler friendliness" which changed pktgen_thread_worker() to
use wait_event_interruptible_timeout().

Reported-by: Huang Ying <redacted>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Interesting that it didn't happen in my tests yet per description it
should have. Huang, did you do anything special to trigger this?

On 08/04, Marcelo Ricardo Leitner wrote:

On Tue, Aug 04, 2015 at 06:33:34PM +0200, Oleg Nesterov wrote:

quoted

Commit 1fbe4b46caca "net: pktgen: kill the Wait for kthread_stop
code in pktgen_thread_worker()" removed (in particular) the final
__set_current_state(TASK_RUNNING) and I didn't notice the previous
set_current_state(TASK_INTERRUPTIBLE). This triggers the warning
in __might_sleep() after return.

Afaics, we can simply remove both set_current_state()'s, and we
could do this a long ago right after ef87979c273a2 "pktgen: better
scheduler friendliness" which changed pktgen_thread_worker() to
use wait_event_interruptible_timeout().

Reported-by: Huang Ying <redacted>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Interesting that it didn't happen in my tests yet per description it
should have. Huang, did you do anything special to trigger this?

Do you have CONFIG_DEBUG_ATOMIC_SLEEP=y ?

Oleg.

On Tue, Aug 04, 2015 at 07:08:27PM +0200, Oleg Nesterov wrote:

On 08/04, Marcelo Ricardo Leitner wrote:

quoted

On Tue, Aug 04, 2015 at 06:33:34PM +0200, Oleg Nesterov wrote:

quoted

Commit 1fbe4b46caca "net: pktgen: kill the Wait for kthread_stop
code in pktgen_thread_worker()" removed (in particular) the final
__set_current_state(TASK_RUNNING) and I didn't notice the previous
set_current_state(TASK_INTERRUPTIBLE). This triggers the warning
in __might_sleep() after return.

Afaics, we can simply remove both set_current_state()'s, and we
could do this a long ago right after ef87979c273a2 "pktgen: better
scheduler friendliness" which changed pktgen_thread_worker() to
use wait_event_interruptible_timeout().

Reported-by: Huang Ying <redacted>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Interesting that it didn't happen in my tests yet per description it
should have. Huang, did you do anything special to trigger this?

Do you have CONFIG_DEBUG_ATOMIC_SLEEP=y ?

Ahh yes, probably not. Thanks.

  Marcelo

From: Oleg Nesterov <oleg@redhat.com>
Date: Tue, 4 Aug 2015 18:33:34 +0200

Commit 1fbe4b46caca "net: pktgen: kill the Wait for kthread_stop
code in pktgen_thread_worker()" removed (in particular) the final
__set_current_state(TASK_RUNNING) and I didn't notice the previous
set_current_state(TASK_INTERRUPTIBLE). This triggers the warning
in __might_sleep() after return.

Afaics, we can simply remove both set_current_state()'s, and we
could do this a long ago right after ef87979c273a2 "pktgen: better
scheduler friendliness" which changed pktgen_thread_worker() to
use wait_event_interruptible_timeout().

Reported-by: Huang Ying <redacted>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Applied, thank you.