[PATCH 6.6.y] 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN

[PATCH 6.6.y] 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN

[driz2t]

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Hi,

Please test this patch on stable 6.6.y.


#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git c09fbcd31ae6d71e7c69545839bec92d8e15c13b


Thanks,
Changjian Liu

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--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -654,34 +654,31 @@
 /**
  * p9_fd_request - send 9P request
  * The function can sleep until the request is scheduled for sending.
  * The function can be interrupted. Return from the function is not
  * a guarantee that the request is sent successfully.
  *
  * @client: client instance
  * @req: request to be sent
  *
  */
 
 static int p9_fd_request(struct p9_client *client, struct p9_req_t *req)
 {
 	__poll_t n;
 	struct p9_trans_fd *ts = client->trans;
 	struct p9_conn *m = &ts->conn;
 
 	p9_debug(P9_DEBUG_TRANS, "mux %p task %p tcall %p id %d\n",
 		 m, current, &req->tc, req->tc.id);
 	if (m->err < 0)
 		return m->err;
 
 	spin_lock(&m->req_lock);
 	WRITE_ONCE(req->status, REQ_STATUS_UNSENT);
 	list_add_tail(&req->req_list, &m->unsent_req_list);
 	spin_unlock(&m->req_lock);
 
-	if (test_and_clear_bit(Wpending, &m->wsched))
-		n = EPOLLOUT;
-	else
-		n = p9_fd_poll(m->client, NULL, NULL);
+ p9_poll_mux(m);
 
 	if (n & EPOLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
 		schedule_work(&m->wq);

Re: [v6.6] INFO: task hung in iterate_supers

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file net/9p/trans_fd.c
Hunk #1 FAILED at 654.
1 out of 1 hunk FAILED



Tested on:

commit:         c09fbcd3 Linux 6.6.130
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
kernel config:  https://syzkaller.appspot.com/x/.config?x=12606d4b8832c7e4
dashboard link: https://syzkaller.appspot.com/bug?extid=739c128b5557abb9f816
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=14523752580000