From d6f977830c164ee079c68101595c28ff1847f88f Mon Sep 17 00:00:00 2001 From: Andrew Deason Date: Tue, 20 Dec 2011 17:44:42 -0500 Subject: [PATCH] viced: Keep H_LOCK while locking host in h_Alloc_r Currently in h_Alloc_r, we h_Lock_r the host, so we have it locked on return. However, h_Lock_r drops the host glock, which is bad in this situation since we have already added the host to the global hash table, so other threads may see it. This can mean that by the time h_Alloc_r returns, the returned host may have HOSTDELETED set, and/or the addresses associated with the host may be completely different. h_Alloc_r's caller, h_GetHost_r, seems to assume that the host is still associated with the address of the passed-in connection. When this is not true, this can result in the host structure getting into a strange state, such as the primary addr/port may not be hashed. The host may also have HOSTDELETED set, in which case we're not supposed to be dealing with it at all. To avoid these problems, lock host->lock directly in h_Alloc_r, without going through h_Lock_r and dropping H_LOCK. Also do it as one of the first things we do to initialize the host, just to make sure that if anybody else happens to see the host, it is locked by us when they do. Change-Id: Ia99cb84ad94f3e143ed0bae33485a88d60ff5b27 Reviewed-on: http://gerrit.openafs.org/6389 Tested-by: BuildBot Reviewed-by: Derrick Brashear --- src/viced/host.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/src/viced/host.c b/src/viced/host.c index 4922c8332f..08632b082c 100644 --- a/src/viced/host.c +++ b/src/viced/host.c @@ -654,6 +654,12 @@ h_Alloc_r(struct rx_connection *r_con) if (!host) return NULL; + h_Hold_r(host); + /* acquire the host lock withot dropping H_LOCK. we can do this here + * because we know we will not block; we just created this host and + * nobody else knows about it. */ + ObtainWriteLock(&host->lock); + host->host = rxr_HostOf(r_con); host->port = rxr_PortOf(r_con); @@ -685,8 +691,6 @@ h_Alloc_r(struct rx_connection *r_con) h_gethostcps(host); /* do this under host hold/lock */ #endif host->FirstClient = NULL; - h_Hold_r(host); - h_Lock_r(host); h_InsertList_r(host); /* update global host List */ /* * Compare the new host's IP address (in host byte order) with ours