diff options
| author | Tim Gardner <tim.gardner@canonical.com> | 2013-02-13 08:40:16 -0700 |
|---|---|---|
| committer | J. Bruce Fields <bfields@redhat.com> | 2013-02-15 11:29:38 -0500 |
| commit | f25cc71e634edcf8a15bc60a48f2b5f3ec9fbb1d (patch) | |
| tree | b66f98dacd1c095dfded8ee673290230366dd8c8 | |
| parent | deb4534f4f3be7aea7d9d24c3b0d58f370cbf9ef (diff) | |
| download | lwn-f25cc71e634edcf8a15bc60a48f2b5f3ec9fbb1d.tar.gz lwn-f25cc71e634edcf8a15bc60a48f2b5f3ec9fbb1d.zip | |
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>
| -rw-r--r-- | fs/lockd/clntlock.c | 12 | ||||
| -rw-r--r-- | fs/lockd/clntproc.c | 6 | ||||
| -rw-r--r-- | include/linux/lockd/lockd.h | 3 |
3 files changed, 15 insertions, 6 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); diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h index f5a051a79273..a395f1e7998f 100644 --- a/include/linux/lockd/lockd.h +++ b/include/linux/lockd/lockd.h @@ -212,7 +212,8 @@ int nlmclnt_block(struct nlm_wait *block, struct nlm_rqst *req, long timeout) __be32 nlmclnt_grant(const struct sockaddr *addr, const struct nlm_lock *lock); void nlmclnt_recovery(struct nlm_host *); -int nlmclnt_reclaim(struct nlm_host *, struct file_lock *); +int nlmclnt_reclaim(struct nlm_host *, struct file_lock *, + struct nlm_rqst *); void nlmclnt_next_cookie(struct nlm_cookie *); /* |