Eric Lee / smarc-ti-linux-kernel

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Commit f25cc71e634edcf8a15bc60a48f2b5f3ec9fbb1d

Authored by Tim Gardner
Committed by J. Bruce Fields
1 parent deb4534f4f
Exists in master and in 20 other branches dlt-processor-sdk-linux-03.00.00.04, newt-ti-linux-3.12.y, processor-sdk-linux-01.00.00, processor-sdk-linux-02.00.01, smarc-ti-linux-3.12.10, smarc-ti-linux-3.12.y, smarc-ti-linux-3.14.y, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.12.y, ti-linux-3.14.y, ti-linux-3.15.y, ti-lsk-linux-4.1.y

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>

Showing 3 changed files with 15 additions and 6 deletions Side-by-side Diff

... ... @@ -220,10 +220,19 @@
220 220 {
221 221 struct nlm_host *host = (struct nlm_host *) ptr;
222 222 struct nlm_wait *block;
  223 + struct nlm_rqst *req;
223 224 struct file_lock *fl, *next;
224 225 u32 nsmstate;
225 226 struct net *net = host->net;
226 227  
  228 + req = kmalloc(sizeof(*req), GFP_KERNEL);
  229 + if (!req) {
  230 + printk(KERN_ERR "lockd: reclaimer unable to alloc memory."
  231 + " Locks for %s won't be reclaimed!\n",
  232 + host->h_name);
  233 + return 0;
  234 + }
  235 +
227 236 allow_signal(SIGKILL);
228 237  
229 238 down_write(&host->h_rwsem);
... ... @@ -253,7 +262,7 @@
253 262 */
254 263 if (signalled())
255 264 continue;
256   - if (nlmclnt_reclaim(host, fl) != 0)
  265 + if (nlmclnt_reclaim(host, fl, req) != 0)
257 266 continue;
258 267 list_add_tail(&fl->fl_u.nfs_fl.list, &host->h_granted);
259 268 if (host->h_nsmstate != nsmstate) {
... ... @@ -279,6 +288,7 @@
279 288 /* Release host handle after use */
280 289 nlmclnt_release_host(host);
281 290 lockd_down(net);
  291 + kfree(req);
282 292 return 0;
283 293 }
... ... @@ -615,17 +615,15 @@
615 615 * RECLAIM: Try to reclaim a lock
616 616 */
617 617 int
618   -nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
  618 +nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl,
  619 + struct nlm_rqst *req)
619 620 {
620   - struct nlm_rqst reqst, *req;
621 621 int status;
622 622  
623   - req = &reqst;
624 623 memset(req, 0, sizeof(*req));
625 624 locks_init_lock(&req->a_args.lock.fl);
626 625 locks_init_lock(&req->a_res.lock.fl);
627 626 req->a_host = host;
628   - req->a_flags = 0;
629 627  
630 628 /* Set up the argument struct */
631 629 nlmclnt_setlockargs(req, fl);
include/linux/lockd/lockd.h
Diff comments   View file @ f25cc71
... ... @@ -212,7 +212,8 @@
212 212 __be32 nlmclnt_grant(const struct sockaddr *addr,
213 213 const struct nlm_lock *lock);
214 214 void nlmclnt_recovery(struct nlm_host *);
215   -int nlmclnt_reclaim(struct nlm_host *, struct file_lock *);
  215 +int nlmclnt_reclaim(struct nlm_host *, struct file_lock *,
  216 + struct nlm_rqst *);
216 217 void nlmclnt_next_cookie(struct nlm_cookie *);
217 218  
218 219 /*