Module Name: src
Committed By: riastradh
Date: Tue Sep 8 16:39:58 UTC 2020
Modified Files:
src/sys/net: if_wg.c
Log Message:
wg: Drop wgp_lock while waiting for endpoint psref to drain.
- This is safe because wgp_endpoint_changing locks out any attempts
to change the endpoint until the draining is complete.
- This is necessary to avoid a deadlock where the handshake thread
holds a psref and awaits mutex_enter(wgp->wgp_lock).
XXX The same deadlock may occur in wg_destroy_session. Not clear
that it's safe to just release wgp_lock there; may need to create a
new session state, say WGS_STATE_DRAINING, while we wait for
psref_target_destroy. But this needs a little more thought; a new
state may not be necessary, and would be nice to avoid if not
necessary.
To generate a diff of this commit:
cvs rdiff -u -r1.55 -r1.56 src/sys/net/if_wg.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/net/if_wg.c
diff -u src/sys/net/if_wg.c:1.55 src/sys/net/if_wg.c:1.56
--- src/sys/net/if_wg.c:1.55 Mon Sep 7 01:15:25 2020
+++ src/sys/net/if_wg.c Tue Sep 8 16:39:57 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: if_wg.c,v 1.55 2020/09/07 01:15:25 riastradh Exp $ */
+/* $NetBSD: if_wg.c,v 1.56 2020/09/08 16:39:57 riastradh Exp $ */
/*
* Copyright (C) Ryota Ozaki <[email protected]>
@@ -41,7 +41,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_wg.c,v 1.55 2020/09/07 01:15:25 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_wg.c,v 1.56 2020/09/08 16:39:57 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_inet.h"
@@ -2965,10 +2965,12 @@ wg_task_endpoint_changed(struct wg_softc
if (atomic_load_relaxed(&wgp->wgp_endpoint_changing)) {
pserialize_perform(wgp->wgp_psz);
+ mutex_exit(wgp->wgp_lock);
psref_target_destroy(&wgp->wgp_endpoint0->wgsa_psref,
wg_psref_class);
psref_target_init(&wgp->wgp_endpoint0->wgsa_psref,
wg_psref_class);
+ mutex_enter(wgp->wgp_lock);
atomic_store_release(&wgp->wgp_endpoint_changing, 0);
}
}
