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Subject[PATCH linux-next] lockd: nlmsvc_mark_resources(): avoid stack overflow
Date
Dynamically allocate the NLM host structure in order to avoid stack overflow.
nlmsvc_mark_resources() is several call levels deep in a stack
that has a number of large variables. 512 bytes seems like a lot
on the stack at this point.

smatch analysis:

fs/lockd/svcsubs.c:366 nlmsvc_mark_resources() warn: 'hint' puts
512 bytes on stack

Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: linux-nfs@vger.kernel.org
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---
fs/lockd/svcsubs.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index b904f41..f3abb7f 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -363,11 +363,15 @@ nlmsvc_is_client(void *data, struct nlm_host *dummy)
void
nlmsvc_mark_resources(struct net *net)
{
- struct nlm_host hint;
+ struct nlm_host *hint = kzalloc(sizeof(*hint), GFP_KERNEL);

- dprintk("lockd: nlmsvc_mark_resources for net %p\n", net);
- hint.net = net;
- nlm_traverse_files(&hint, nlmsvc_mark_host, NULL);
+ if (hint) {
+ dprintk("lockd: nlmsvc_mark_resources for net %p\n", net);
+ hint->net = net;
+ nlm_traverse_files(hint, nlmsvc_mark_host, NULL);
+ }
+
+ kfree(hint);
}

/*
--
1.7.9.5


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