* [PATCH] nfsd: destroy percpu stats counters after reply cache shutdown
@ 2022-05-23 18:52 Julian Schroeder
2022-05-23 19:25 ` Chuck Lever III
0 siblings, 1 reply; 3+ messages in thread
From: Julian Schroeder @ 2022-05-23 18:52 UTC (permalink / raw)
To: Chuck Lever, Amir Goldstein, linux-nfs, linux-kernel
Cc: benh, alisaidi, jumaco
From: Julian Schroeder <jumaco@amazon.com>
Upon nfsd shutdown any pending DRC cache is freed. DRC cache use is
tracked via a percpu counter. In the current code the percpu counter
is destroyed before. If any pending cache is still present,
percpu_counter_add is called with a percpu counter==NULL. This causes
a kernel crash.
The solution is to destroy the percpu counter after the cache is freed.
Fixes: e567b98ce9a4b (“nfsd: protect concurrent access to nfsd stats counters”)
Signed-off-by: Julian Schroeder <jumaco@amazon.com>
---
fs/nfsd/nfscache.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index 0b3f12aa37ff..7da88bdc0d6c 100644
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -206,7 +206,6 @@ void nfsd_reply_cache_shutdown(struct nfsd_net *nn)
struct svc_cacherep *rp;
unsigned int i;
- nfsd_reply_cache_stats_destroy(nn);
unregister_shrinker(&nn->nfsd_reply_cache_shrinker);
for (i = 0; i < nn->drc_hashsize; i++) {
@@ -217,6 +216,7 @@ void nfsd_reply_cache_shutdown(struct nfsd_net *nn)
rp, nn);
}
}
+ nfsd_reply_cache_stats_destroy(nn);
kvfree(nn->drc_hashtbl);
nn->drc_hashtbl = NULL;
--
2.32.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] nfsd: destroy percpu stats counters after reply cache shutdown
2022-05-23 18:52 [PATCH] nfsd: destroy percpu stats counters after reply cache shutdown Julian Schroeder
@ 2022-05-23 19:25 ` Chuck Lever III
0 siblings, 0 replies; 3+ messages in thread
From: Chuck Lever III @ 2022-05-23 19:25 UTC (permalink / raw)
To: Julian Schroeder
Cc: Amir Goldstein, Linux NFS Mailing List, LKML, benh, alisaidi, jumaco
> On May 23, 2022, at 2:52 PM, Julian Schroeder <jumaco@dev-dsk-jumaco-1e-78723413.us-east-1.amazon.com> wrote:
>
> From: Julian Schroeder <jumaco@amazon.com>
>
> Upon nfsd shutdown any pending DRC cache is freed. DRC cache use is
> tracked via a percpu counter. In the current code the percpu counter
> is destroyed before. If any pending cache is still present,
> percpu_counter_add is called with a percpu counter==NULL. This causes
> a kernel crash.
> The solution is to destroy the percpu counter after the cache is freed.
>
> Fixes: e567b98ce9a4b (“nfsd: protect concurrent access to nfsd stats counters”)
> Signed-off-by: Julian Schroeder <jumaco@amazon.com>
> ---
> fs/nfsd/nfscache.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
> index 0b3f12aa37ff..7da88bdc0d6c 100644
> --- a/fs/nfsd/nfscache.c
> +++ b/fs/nfsd/nfscache.c
> @@ -206,7 +206,6 @@ void nfsd_reply_cache_shutdown(struct nfsd_net *nn)
> struct svc_cacherep *rp;
> unsigned int i;
>
> - nfsd_reply_cache_stats_destroy(nn);
> unregister_shrinker(&nn->nfsd_reply_cache_shrinker);
>
> for (i = 0; i < nn->drc_hashsize; i++) {
> @@ -217,6 +216,7 @@ void nfsd_reply_cache_shutdown(struct nfsd_net *nn)
> rp, nn);
> }
> }
> + nfsd_reply_cache_stats_destroy(nn);
>
> kvfree(nn->drc_hashtbl);
> nn->drc_hashtbl = NULL;
> --
> 2.32.0
>
Thank you, Julian. Patch applied to the NFSD for-5.19 topic branch.
--
Chuck Lever
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] nfsd: destroy percpu stats counters after reply cache shutdown
@ 2022-05-26 14:28 Julian Schroeder
0 siblings, 0 replies; 3+ messages in thread
From: Julian Schroeder @ 2022-05-26 14:28 UTC (permalink / raw)
To: stable; +Cc: Julian Schroeder
Upon nfsd shutdown any pending DRC cache is freed. DRC cache use is
tracked via a percpu counter. In the current code the percpu counter
is destroyed before. If any pending cache is still present,
percpu_counter_add is called with a percpu counter==NULL. This causes
a kernel crash.
The solution is to destroy the percpu counter after the cache is freed.
Fixes: e567b98ce9a4b (“nfsd: protect concurrent access to nfsd stats counters”)
Signed-off-by: Julian Schroeder <jumaco@amazon.com>
---
fs/nfsd/nfscache.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index 0b3f12aa37ff..7da88bdc0d6c 100644
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -206,7 +206,6 @@ void nfsd_reply_cache_shutdown(struct nfsd_net *nn)
struct svc_cacherep *rp;
unsigned int i;
- nfsd_reply_cache_stats_destroy(nn);
unregister_shrinker(&nn->nfsd_reply_cache_shrinker);
for (i = 0; i < nn->drc_hashsize; i++) {
@@ -217,6 +216,7 @@ void nfsd_reply_cache_shutdown(struct nfsd_net *nn)
rp, nn);
}
}
+ nfsd_reply_cache_stats_destroy(nn);
kvfree(nn->drc_hashtbl);
nn->drc_hashtbl = NULL;
--
2.32.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-05-26 14:28 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2022-05-23 18:52 [PATCH] nfsd: destroy percpu stats counters after reply cache shutdown Julian Schroeder
2022-05-23 19:25 ` Chuck Lever III
2022-05-26 14:28 Julian Schroeder
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