From c9a1f766ab1c154c4ef9f2211285f5021c3bfd73 Mon Sep 17 00:00:00 2001 From: Alex Zenla Date: Tue, 19 Nov 2024 21:16:33 +0000 Subject: [PATCH] 9p/xen: fix init sequence [ Upstream commit 7ef3ae82a6ebbf4750967d1ce43bcdb7e44ff74b ] Large amount of mount hangs observed during hotplugging of 9pfs devices. The 9pfs Xen driver attempts to initialize itself more than once, causing the frontend and backend to disagree: the backend listens on a channel that the frontend does not send on, resulting in stalled processing. Only allow initialization of 9p frontend once. Fixes: c15fe55d14b3b ("9p/xen: fix connection sequence") Signed-off-by: Alex Zenla Signed-off-by: Alexander Merritt Signed-off-by: Ariadne Conill Reviewed-by: Juergen Gross Message-ID: <20241119211633.38321-1-alexander@edera.dev> Signed-off-by: Dominique Martinet Signed-off-by: Sasha Levin --- net/9p/trans_xen.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c index c87146a49636..77d7e6c3d7a2 100644 --- a/net/9p/trans_xen.c +++ b/net/9p/trans_xen.c @@ -480,6 +480,7 @@ static int xen_9pfs_front_init(struct xenbus_device *dev) goto error; } + xenbus_switch_state(dev, XenbusStateInitialised); return 0; error_xenbus: @@ -527,8 +528,10 @@ static void xen_9pfs_front_changed(struct xenbus_device *dev, break; case XenbusStateInitWait: - if (!xen_9pfs_front_init(dev)) - xenbus_switch_state(dev, XenbusStateInitialised); + if (dev->state != XenbusStateInitialising) + break; + + xen_9pfs_front_init(dev); break; case XenbusStateConnected: