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From: Anna Schumaker <schumaker.anna@gmail.com>
To: Trond Myklebust <trondmy@hammerspace.com>,
	"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH v2 28/28] NFS: Remove redundant open context from nfs_page
Date: Mon, 08 Apr 2019 13:11:31 -0400	[thread overview]
Message-ID: <89770990a66eb25000248daaf2b0b8fcf105c8d7.camel@gmail.com> (raw)
In-Reply-To: <9498d534b8e59f903bf750183a08d22a6ae7ba9a.camel@hammerspace.com>

On Sat, 2019-04-06 at 14:14 +0000, Trond Myklebust wrote:
> Hi Anna
> 
> On Fri, 2019-04-05 at 15:42 -0400, Anna Schumaker wrote:
> > Hi Trond,
> > 
> > I'm having some trouble with xfstests generic/464 after applying this
> > patch.
> > Here is the oops I'm getting, I'm able to reproduce it fairly easily
> > against all
> > NFS versions: 
> > 
> > [   41.182015] BUG: unable to handle kernel NULL pointer dereference
> > at
> > 0000000000000048
> > [   41.182051] #PF error: [normal kernel read fault]
> > [   41.182071] PGD 0 P4D 0 
> > [   41.182086] Oops: 0000 [#1] PREEMPT SMP PTI
> > [   41.182104] CPU: 1 PID: 14515 Comm: kworker/1:6 Not tainted 5.1.0-
> > rc3-ANNA+
> > #5292
> > [   41.182131] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
> > [   41.182174] Workqueue: nfsiod rpc_async_release [sunrpc]
> > [   41.182209] RIP: 0010:__put_nfs_open_context+0xd/0x110 [nfs]
> > [   41.182227] Code: f8 ba a8 00 00 00 be c0 0c 00 00 e8 5d c0 58 f7
> > 48 89 c3 48
> > 85 c0 74 c5 e9 15 ff ff ff 0f 1f 44 00 00 41 56 41 55 41 54 55 53
> > <48> 8b 47 48
> > 48 8b 68 30 4c 8b 60 68 f0 ff 0f 0f 88 14 53 01 00 74
> > [   41.182267] RSP: 0018:ffffae5f04b6be30 EFLAGS: 00010246
> > [   41.182279] RAX: 0000000000000000 RBX: ffffa22aae71a680 RCX:
> > 0000000000000000
> > [   41.182295] RDX: ffffffffb9205dc8 RSI: 0000000000000000 RDI:
> > 0000000000000000
> > [   41.182311] RBP: 0000000000000801 R08: ffffa22aa5ca0000 R09:
> > ffffa22aba267800
> > [   41.182327] R10: 0000000000000000 R11: 0000000000000000 R12:
> > ffffce5effd1c200
> > [   41.182351] R13: 0000000000000000 R14: ffffa22aad2aa6c0 R15:
> > 0ffffce5effd1c20
> > [   41.182378] FS:  0000000000000000(0000) GS:ffffa22abcb00000(0000)
> > knlGS:0000000000000000
> > [   41.182411] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [   41.182435] CR2: 0000000000000048 CR3: 00000000af972005 CR4:
> > 0000000000160ee0
> > [   41.182468] Call Trace:
> > [   41.182495]  nfs_commitdata_release+0x15/0x30 [nfs]
> > [   41.182536]  rpc_free_task+0x39/0x70 [sunrpc]
> > [   41.182571]  rpc_async_release+0x29/0x40 [sunrpc]
> > [   41.182594]  process_one_work+0x1eb/0x410
> > [   41.182611]  worker_thread+0x2d/0x3d0
> > [   41.182621]  ? process_one_work+0x410/0x410
> > [   41.182632]  kthread+0x112/0x130
> > [   41.182641]  ? kthread_park+0x80/0x80
> > [   41.182652]  ret_from_fork+0x35/0x40
> > [   41.182662] Modules linked in: nfsv3 nfs fscache rpcrdma ib_isert
> > 
> 
> Does the following patch help to fix this?

This patch does fix the problem. Thanks!

Anna

> 
> Cheers
>   Trond
> 
> 8<---------------------------------------
> From d84c699bba78d66d3ccd3f76a6aae573bdfddc05 Mon Sep 17 00:00:00 2001
> From: Trond Myklebust <trond.myklebust@hammerspace.com>
> Date: Sat, 6 Apr 2019 10:05:55 -0400
> Subject: [PATCH] NFS: Ensure that all nfs lock contexts have a valid open
>  context
> 
> Force the lock context to keep a reference to the parent open
> context so that we can guarantee the validity of the latter.
> 
> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
> ---
>  fs/nfs/inode.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
> index 414a90d48493..efc45f22c581 100644
> --- a/fs/nfs/inode.c
> +++ b/fs/nfs/inode.c
> @@ -885,10 +885,14 @@ struct nfs_lock_context *nfs_get_lock_context(struct
> nfs_open_context *ctx)
>  		spin_lock(&inode->i_lock);
>  		res = __nfs_find_lock_context(ctx);
>  		if (res == NULL) {
> -			list_add_tail_rcu(&new->list, &ctx->lock_context.list);
> -			new->open_context = ctx;
> -			res = new;
> -			new = NULL;
> +			new->open_context = get_nfs_open_context(ctx);
> +			if (new->open_context) {
> +				list_add_tail_rcu(&new->list,
> +						&ctx->lock_context.list);
> +				res = new;
> +				new = NULL;
> +			} else
> +				res = ERR_PTR(-EBADF);
>  		}
>  		spin_unlock(&inode->i_lock);
>  		kfree(new);
> @@ -906,6 +910,7 @@ void nfs_put_lock_context(struct nfs_lock_context *l_ctx)
>  		return;
>  	list_del_rcu(&l_ctx->list);
>  	spin_unlock(&inode->i_lock);
> +	put_nfs_open_context(ctx);
>  	kfree_rcu(l_ctx, rcu_head);
>  }
>  EXPORT_SYMBOL_GPL(nfs_put_lock_context);
> -- 
> 2.20.1
> 
> 
> -- 
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> trond.myklebust@hammerspace.com
> 
> 


  reply	other threads:[~2019-04-08 17:11 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-29 21:59 [PATCH v2 00/28] Fix up soft mounts for NFSv4.x Trond Myklebust
2019-03-29 21:59 ` [PATCH v2 01/28] SUNRPC: Fix up task signalling Trond Myklebust
2019-03-29 21:59   ` [PATCH v2 02/28] SUNRPC: Refactor rpc_restart_call/rpc_restart_call_prepare Trond Myklebust
2019-03-29 21:59     ` [PATCH v2 03/28] SUNRPC: Refactor xprt_request_wait_receive() Trond Myklebust
2019-03-29 21:59       ` [PATCH v2 04/28] SUNRPC: Refactor rpc_sleep_on() Trond Myklebust
2019-03-29 21:59         ` [PATCH v2 05/28] SUNRPC: Remove unused argument 'action' from rpc_sleep_on_priority() Trond Myklebust
2019-03-29 21:59           ` [PATCH v2 06/28] SUNRPC: Add function rpc_sleep_on_timeout() Trond Myklebust
2019-03-29 21:59             ` [PATCH v2 07/28] SUNRPC: Fix up tracking of timeouts Trond Myklebust
2019-03-29 21:59               ` [PATCH v2 08/28] SUNRPC: Simplify queue timeouts using timer_reduce() Trond Myklebust
2019-03-29 21:59                 ` [PATCH v2 09/28] SUNRPC: Declare RPC timers as TIMER_DEFERRABLE Trond Myklebust
2019-03-29 21:59                   ` [PATCH v2 10/28] SUNRPC: Ensure that the transport layer respect major timeouts Trond Myklebust
2019-03-29 21:59                     ` [PATCH v2 11/28] SUNRPC: Add tracking of RPC level errors Trond Myklebust
2019-03-29 21:59                       ` [PATCH v2 12/28] SUNRPC: Make "no retrans timeout" soft tasks behave like softconn for timeouts Trond Myklebust
2019-03-29 21:59                         ` [PATCH v2 13/28] SUNRPC: Start the first major timeout calculation at task creation Trond Myklebust
2019-03-29 21:59                           ` [PATCH v2 14/28] SUNRPC: Ensure to ratelimit the "server not responding" syslog messages Trond Myklebust
2019-03-29 21:59                             ` [PATCH v2 15/28] SUNRPC: Add the 'softerr' rpc_client flag Trond Myklebust
2019-03-29 21:59                               ` [PATCH v2 16/28] NFS: Consider ETIMEDOUT to be a fatal error Trond Myklebust
2019-03-29 21:59                                 ` [PATCH v2 17/28] NFS: Move internal constants out of uapi/linux/nfs_mount.h Trond Myklebust
2019-03-29 21:59                                   ` [PATCH v2 18/28] NFS: Add a mount option "softerr" to allow clients to see ETIMEDOUT errors Trond Myklebust
2019-03-29 21:59                                     ` [PATCH v2 19/28] NFS: Don't interrupt file writeout due to fatal errors Trond Myklebust
2019-03-29 21:59                                       ` [PATCH v2 20/28] NFS: Don't call generic_error_remove_page() while holding locks Trond Myklebust
2019-03-29 21:59                                         ` [PATCH v2 21/28] NFS: Don't inadvertently clear writeback errors Trond Myklebust
2019-03-29 21:59                                           ` [PATCH v2 22/28] NFS: Replace custom error reporting mechanism with generic one Trond Myklebust
2019-03-29 21:59                                             ` [PATCH v2 23/28] NFS: Fix up NFS I/O subrequest creation Trond Myklebust
2019-03-29 21:59                                               ` [PATCH v2 24/28] NFS: Remove unused argument from nfs_create_request() Trond Myklebust
2019-03-29 21:59                                                 ` [PATCH v2 25/28] pNFS: Add tracking to limit the number of pNFS retries Trond Myklebust
2019-03-29 21:59                                                   ` [PATCH v2 26/28] NFS: Allow signal interruption of NFS4ERR_DELAYed operations Trond Myklebust
2019-03-29 21:59                                                     ` [PATCH v2 27/28] NFS: Add a helper to return a pointer to the open context of a struct nfs_page Trond Myklebust
2019-03-29 21:59                                                       ` [PATCH v2 28/28] NFS: Remove redundant open context from nfs_page Trond Myklebust
2019-04-05 19:42                                                         ` Anna Schumaker
2019-04-06 14:14                                                           ` Trond Myklebust
2019-04-08 17:11                                                             ` Anna Schumaker [this message]
2019-04-08 18:13                                                               ` Trond Myklebust
2019-04-08 18:15                                                                 ` Anna Schumaker
2019-04-01 16:27                                                   ` [PATCH v2 25/28] pNFS: Add tracking to limit the number of pNFS retries Olga Kornievskaia
2019-04-02 18:23                                                     ` Trond Myklebust
2019-04-01 16:54 ` [PATCH v2 00/28] Fix up soft mounts for NFSv4.x Olga Kornievskaia
2019-04-02 18:28   ` Trond Myklebust
2019-04-03 20:51     ` Mkrtchyan, Tigran
2019-04-03 21:13       ` Trond Myklebust
2019-04-03 21:59         ` Mkrtchyan, Tigran
2019-04-03 22:10           ` Trond Myklebust

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