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nfsd: fix oops when reading pool_stats before server is started

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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: 7b207ccd98 ("svc: don't hold reference for poolstats, only mutex.")
Reported-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Jeff Layton 2024-06-17 07:54:08 -04:00 committed by Chuck Lever
parent 4a77c3dead
commit 8e948c365d
1 changed files with 5 additions and 3 deletions
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8
net/sunrpc/svc_xprt.c
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@ -1421,12 +1421,13 @@ 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];
}
@ -1458,7 +1459,8 @@ 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)