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authorTrond Myklebust <Trond.Myklebust@netapp.com>2010-09-12 19:55:25 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2010-09-12 19:55:25 -0400
commit5a67657a2e90c9e4a48518f95d4ba7777aa20fbb (patch)
treebd98ad7f5261afc7ae9ba804937d9ce2fb9e8764 /net
parentf2d47d02fd84343a3c5452daca6ed12c75618aff (diff)
SUNRPC: Fix race corrupting rpc upcall
If rpc_queue_upcall() adds a new upcall to the rpci->pipe list just after rpc_pipe_release calls rpc_purge_list(), but before it calls gss_pipe_release (as rpci->ops->release_pipe(inode)), then the latter will free a message without deleting it from the rpci->pipe list. We will be left with a freed object on the rpc->pipe list. Most frequent symptoms are kernel crashes in rpc.gssd system calls on the pipe in question. Reported-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: stable@kernel.org
Diffstat (limited to 'net')
-rw-r--r--net/sunrpc/auth_gss/auth_gss.c9
-rw-r--r--net/sunrpc/rpc_pipe.c6
2 files changed, 8 insertions, 7 deletions
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index dcfc66bab2bb..12c485982814 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -745,17 +745,18 @@ gss_pipe_release(struct inode *inode)
struct rpc_inode *rpci = RPC_I(inode);
struct gss_upcall_msg *gss_msg;
+restart:
spin_lock(&inode->i_lock);
- while (!list_empty(&rpci->in_downcall)) {
+ list_for_each_entry(gss_msg, &rpci->in_downcall, list) {
- gss_msg = list_entry(rpci->in_downcall.next,
- struct gss_upcall_msg, list);
+ if (!list_empty(&gss_msg->msg.list))
+ continue;
gss_msg->msg.errno = -EPIPE;
atomic_inc(&gss_msg->count);
__gss_unhash_msg(gss_msg);
spin_unlock(&inode->i_lock);
gss_release_msg(gss_msg);
- spin_lock(&inode->i_lock);
+ goto restart;
}
spin_unlock(&inode->i_lock);
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 95ccbcf45d3e..41a762f82630 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -48,7 +48,7 @@ static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
return;
do {
msg = list_entry(head->next, struct rpc_pipe_msg, list);
- list_del(&msg->list);
+ list_del_init(&msg->list);
msg->errno = err;
destroy_msg(msg);
} while (!list_empty(head));
@@ -208,7 +208,7 @@ rpc_pipe_release(struct inode *inode, struct file *filp)
if (msg != NULL) {
spin_lock(&inode->i_lock);
msg->errno = -EAGAIN;
- list_del(&msg->list);
+ list_del_init(&msg->list);
spin_unlock(&inode->i_lock);
rpci->ops->destroy_msg(msg);
}
@@ -268,7 +268,7 @@ rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
if (res < 0 || msg->len == msg->copied) {
filp->private_data = NULL;
spin_lock(&inode->i_lock);
- list_del(&msg->list);
+ list_del_init(&msg->list);
spin_unlock(&inode->i_lock);
rpci->ops->destroy_msg(msg);
}

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