On Fri, Aug 06, 2010 at 06:05:37PM -0400, J. Bruce Fields wrote:
> On Fri, Aug 06, 2010 at 05:27:28PM -0400, J. Bruce Fields wrote:
> > Bah, so what you were hitting was simple--I just moved the
> > nfsd_reset_versions() call to the wrong place; the below should fix it.
> >
> > There's also a couple other bugs in the area.
And also there was one more problem with my original "nfsd: fix
startup/shutdown order bug": it doesn't work to use sv_nrthreads
changing from zero to nonzero as the signal for when to do all this
startup, because write_pool_threads() adjusts the number of threads
without calling nfsd_svc(). (Maybe that should be fixed.)
For now, just use the nfsd_up variable to keep track of this (which is a
little closer to Jeff's original solution).
This is a replacement.
--b.
commit 4cd7eb015e92f7cefb43eaab3e111d1b3c7b3cbf
Author: J. Bruce Fields <bfields@xxxxxxxxxx>
Date: Mon Aug 2 14:12:44 2010 -0400
nfsd: fix startup/shutdown order bug
We must create the server before we can call init_socks or check the
number of threads.
Symptoms were a NULL pointer dereference in nfsd_svc(). Problem
identified by Jeff Layton.
Also fix a minor cleanup-on-error case in nfsd_startup().
Reported-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 92173bd..2a20f89 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -204,6 +204,9 @@ static bool nfsd_up = false;
static int nfsd_startup(unsigned short port, int nrservs)
{
int ret;
+
+ if (nfsd_up)
+ return 0;
/*
* Readahead param cache - will no-op if it already exists.
* (Note therefore results will be suboptimal if number of
@@ -217,7 +220,7 @@ static int nfsd_startup(unsigned short port, int nrservs)
goto out_racache;
ret = lockd_up();
if (ret)
- return ret;
+ goto out_racache;
ret = nfs4_state_start();
if (ret)
goto out_lockd;
@@ -420,7 +423,7 @@ int
nfsd_svc(unsigned short port, int nrservs)
{
int error;
- bool first_thread;
+ bool nfsd_up_before;
mutex_lock(&nfsd_mutex);
dprintk("nfsd: creating service\n");
@@ -432,29 +435,29 @@ nfsd_svc(unsigned short port, int nrservs)
if (nrservs == 0 && nfsd_serv == NULL)
goto out;
- first_thread = (nfsd_serv->sv_nrthreads == 0) && (nrservs != 0);
-
- if (first_thread) {
- error = nfsd_startup(port, nrservs);
- if (error)
- goto out;
- }
error = nfsd_create_serv();
if (error)
- goto out_shutdown;
- error = svc_set_num_threads(nfsd_serv, NULL, nrservs);
+ goto out;
+
+ nfsd_up_before = nfsd_up;
+
+ error = nfsd_startup(port, nrservs);
if (error)
goto out_destroy;
+ }
+ error = svc_set_num_threads(nfsd_serv, NULL, nrservs);
+ if (error)
+ goto out_shutdown;
/* We are holding a reference to nfsd_serv which
* we don't want to count in the return value,
* so subtract 1
*/
error = nfsd_serv->sv_nrthreads - 1;
-out_destroy:
- svc_destroy(nfsd_serv); /* Release server */
out_shutdown:
- if (error < 0 && first_thread)
+ if (error < 0 && !nfsd_up_before)
nfsd_shutdown();
+out_destroy:
+ svc_destroy(nfsd_serv); /* Release server */
out:
mutex_unlock(&nfsd_mutex);
return error;
--
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