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| author | J. Bruce Fields <bfields@redhat.com> | 2011-06-29 16:49:04 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-08-04 21:58:40 -0700 |
| commit | 83d20a07d3fc171d5d7cddb6ebe2cd7a5fee1047 (patch) | |
| tree | f44cd1bd71d6a3d81645a806fda0876033d53407 /net/sunrpc/svc_xprt.c | |
| parent | 4beae54c192e6f1dee12b70e205b800fd99d1fc7 (diff) | |
| download | lwn-83d20a07d3fc171d5d7cddb6ebe2cd7a5fee1047.tar.gz lwn-83d20a07d3fc171d5d7cddb6ebe2cd7a5fee1047.zip | |
svcrpc: fix list-corrupting race on nfsd shutdown
commit ebc63e531cc6a457595dd110b07ac530eae788c3 upstream.
After commit 3262c816a3d7fb1eaabce633caa317887ed549ae "[PATCH] knfsd:
split svc_serv into pools", svc_delete_xprt (then svc_delete_socket) no
longer removed its xpt_ready (then sk_ready) field from whatever list it
was on, noting that there was no point since the whole list was about to
be destroyed anyway.
That was mostly true, but forgot that a few svc_xprt_enqueue()'s might
still be hanging around playing with the about-to-be-destroyed list, and
could get themselves into trouble writing to freed memory if we left
this xprt on the list after freeing it.
(This is actually functionally identical to a patch made first by Ben
Greear, but with more comments.)
Cc: gnb@fmeh.org
Reported-by: Ben Greear <greearb@candelatech.com>
Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'net/sunrpc/svc_xprt.c')
| -rw-r--r-- | net/sunrpc/svc_xprt.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index ab86b7927f84..bd31208bbb61 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -902,12 +902,13 @@ void svc_delete_xprt(struct svc_xprt *xprt) if (!test_and_set_bit(XPT_DETACHED, &xprt->xpt_flags)) list_del_init(&xprt->xpt_list); /* - * We used to delete the transport from whichever list - * it's sk_xprt.xpt_ready node was on, but we don't actually - * need to. This is because the only time we're called - * while still attached to a queue, the queue itself - * is about to be destroyed (in svc_destroy). + * The only time we're called while xpt_ready is still on a list + * is while the list itself is about to be destroyed (in + * svc_destroy). BUT svc_xprt_enqueue could still be attempting + * to add new entries to the sp_sockets list, so we can't leave + * a freed xprt on it. */ + list_del_init(&xprt->xpt_ready); if (test_bit(XPT_TEMP, &xprt->xpt_flags)) serv->sv_tmpcnt--; spin_unlock_bh(&serv->sv_lock); |