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Message-Id: <20240617-nfsd-next-v1-1-5833b297015a@kernel.org>
Date: Mon, 17 Jun 2024 07:54:08 -0400
From: Jeff Layton <jlayton@...nel.org>
To: Sourabh Jain <sourabhjain@...ux.ibm.com>,
Chuck Lever <chuck.lever@...cle.com>, Neil Brown <neilb@...e.de>,
Olga Kornievskaia <kolga@...app.com>, Dai Ngo <Dai.Ngo@...cle.com>,
Tom Talpey <tom@...pey.com>
Cc: Trond Myklebust <trond.myklebust@...merspace.com>,
Anna Schumaker <anna@...nel.org>, linux-nfs@...r.kernel.org,
linux-kernel@...r.kernel.org, Jeff Layton <jlayton@...nel.org>
Subject: [PATCH] nfsd: fix oops when reading pool_stats before server is
started
Sourbh reported an oops that is triggerable by trying to read the
pool_stats procfile before nfsd had been started. Move the check for a
NULL serv in svc_pool_stats_start above the mutex acquisition, and fix
the stop routine not to unlock the mutex if there is no serv yet.
Fixes: 7b207ccd9833 ("svc: don't hold reference for poolstats, only mutex.")
Reported-by: Sourabh Jain <sourabhjain@...ux.ibm.com>
Signed-off-by: Jeff Layton <jlayton@...nel.org>
---
net/sunrpc/svc_xprt.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index d3735ab3e6d1..b757a8891813 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -1422,12 +1422,13 @@ static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
+ if (!si->serv)
+ return NULL;
+
mutex_lock(si->mutex);
if (!pidx)
return SEQ_START_TOKEN;
- if (!si->serv)
- return NULL;
return pidx > si->serv->sv_nrpools ? NULL
: &si->serv->sv_pools[pidx - 1];
}
@@ -1459,7 +1460,8 @@ static void svc_pool_stats_stop(struct seq_file *m, void *p)
{
struct svc_info *si = m->private;
- mutex_unlock(si->mutex);
+ if (si->serv)
+ mutex_unlock(si->mutex);
}
static int svc_pool_stats_show(struct seq_file *m, void *p)
---
base-commit: 4ddfda417a50309f17aeb85f8d1a9a9efbc7d81c
change-id: 20240617-nfsd-next-8593f73544f5
Best regards,
--
Jeff Layton <jlayton@...nel.org>
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