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authorTim Gardner <tim.gardner@canonical.com>2013-02-13 19:40:16 +0400
committerJ. Bruce Fields <bfields@redhat.com>2013-02-15 20:29:38 +0400
commitf25cc71e634edcf8a15bc60a48f2b5f3ec9fbb1d (patch)
treeb66f98dacd1c095dfded8ee673290230366dd8c8 /fs/lockd
parentdeb4534f4f3be7aea7d9d24c3b0d58f370cbf9ef (diff)
downloadlinux-f25cc71e634edcf8a15bc60a48f2b5f3ec9fbb1d.tar.xz
lockd: nlmclnt_reclaim(): avoid stack overflow
Even though nlmclnt_reclaim() is only one call into the stack frame, 928 bytes on the stack seems like a lot. Recode to dynamically allocate the request structure once from within the reclaimer task, then pass this pointer into nlmclnt_reclaim() for reuse on subsequent calls. smatch analysis: fs/lockd/clntproc.c:620 nlmclnt_reclaim() warn: 'reqst' puts 928 bytes on stack Also remove redundant assignment of 0 after memset. Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Tim Gardner <tim.gardner@canonical.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs/lockd')
-rw-r--r--fs/lockd/clntlock.c12
-rw-r--r--fs/lockd/clntproc.c6
2 files changed, 13 insertions, 5 deletions
diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
index 4885b53e56bd..6cd673d34fb9 100644
--- a/fs/lockd/clntlock.c
+++ b/fs/lockd/clntlock.c
@@ -220,10 +220,19 @@ reclaimer(void *ptr)
{
struct nlm_host *host = (struct nlm_host *) ptr;
struct nlm_wait *block;
+ struct nlm_rqst *req;
struct file_lock *fl, *next;
u32 nsmstate;
struct net *net = host->net;
+ req = kmalloc(sizeof(*req), GFP_KERNEL);
+ if (!req) {
+ printk(KERN_ERR "lockd: reclaimer unable to alloc memory."
+ " Locks for %s won't be reclaimed!\n",
+ host->h_name);
+ return 0;
+ }
+
allow_signal(SIGKILL);
down_write(&host->h_rwsem);
@@ -253,7 +262,7 @@ restart:
*/
if (signalled())
continue;
- if (nlmclnt_reclaim(host, fl) != 0)
+ if (nlmclnt_reclaim(host, fl, req) != 0)
continue;
list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
if (host->h_nsmstate != nsmstate) {
@@ -279,5 +288,6 @@ restart:
/* Release host handle after use */
nlmclnt_release_host(host);
lockd_down(net);
+ kfree(req);
return 0;
}
diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index 54f9e6ce0430..b43114c4332a 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -615,17 +615,15 @@ out_unlock:
* RECLAIM: Try to reclaim a lock
*/
int
-nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
+nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl,
+ struct nlm_rqst *req)
{
- struct nlm_rqst reqst, *req;
int status;
- req = &reqst;
memset(req, 0, sizeof(*req));
locks_init_lock(&req->a_args.lock.fl);
locks_init_lock(&req->a_res.lock.fl);
req->a_host = host;
- req->a_flags = 0;
/* Set up the argument struct */
nlmclnt_setlockargs(req, fl);