Commit ac03629b authored by NeilBrown's avatar NeilBrown Committed by Chuck Lever
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Revert "nfsd: fix oops when reading pool_stats before server is started" 



This reverts commit 8e948c36.

The reverted commit moves a test on a field protected by a mutex outside
of the protection of that mutex, and so is obviously racey.

Depending on how the race goes, si->serv might be NULL when dereferenced
in svc_pool_stats_start(), or svc_pool_stats_stop() might unlock a mutex
that hadn't been locked.

This bug that the commit tried to fix has been addressed by initialising
->mutex earlier.

Fixes: 8e948c36 ("nfsd: fix oops when reading pool_stats before server is started")
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent e0011bca

net/sunrpc/svc_xprt.c

+3 −5
Original line number Diff line number Diff line
@@ -1421,13 +1421,12 @@ 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 +1458,6 @@ static void svc_pool_stats_stop(struct seq_file *m, void *p) 
{

	struct svc_info *si = m->private;



	if (si->serv)

	mutex_unlock(si->mutex);

}