On Mon, Jun 17, 2024 at 07:54:08AM -0400, Jeff Layton wrote:
> 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@xxxxxxxxxxxxx>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
Applied to nfsd-fixes (for 6.10-rc). Thanks!
> ---
> 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@xxxxxxxxxx>
>
--
Chuck Lever
