This is a note to let you know that I've just added the patch titled

NFS: Avoid RCU usage in tracepoints

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: nfs-avoid-rcu-usage-in-tracepoints.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 3944369db701f075092357b511fd9f5755771585 Mon Sep 17 00:00:00 2001

From: Anna Schumaker Anna.Schumaker@Netapp.com Date: Wed, 1 Nov 2017 15:48:43 -0400 Subject: NFS: Avoid RCU usage in tracepoints

From: Anna Schumaker Anna.Schumaker@Netapp.com

commit 3944369db701f075092357b511fd9f5755771585 upstream.

There isn't an obvious way to acquire and release the RCU lock during a tracepoint, so we can't use the rpc_peeraddr2str() function here. Instead, rely on the client's cl_hostname, which should have similar enough information without needing an rcu_dereference().

Reported-by: Dave Jones davej@codemonkey.org.uk Signed-off-by: Anna Schumaker Anna.Schumaker@Netapp.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- fs/nfs/nfs4trace.h | 24 ++++++------------------ 1 file changed, 6 insertions(+), 18 deletions(-)

--- a/fs/nfs/nfs4trace.h +++ b/fs/nfs/nfs4trace.h @@ -201,17 +201,13 @@ DECLARE_EVENT_CLASS(nfs4_clientid_event, TP_ARGS(clp, error),

TP_STRUCT__entry( - __string(dstaddr, - rpc_peeraddr2str(clp->cl_rpcclient, - RPC_DISPLAY_ADDR)) + __string(dstaddr, clp->cl_hostname) __field(int, error) ),

TP_fast_assign( __entry->error = error; - __assign_str(dstaddr, - rpc_peeraddr2str(clp->cl_rpcclient, - RPC_DISPLAY_ADDR)); + __assign_str(dstaddr, clp->cl_hostname); ),

TP_printk( @@ -1103,9 +1099,7 @@ DECLARE_EVENT_CLASS(nfs4_inode_callback_ __field(dev_t, dev) __field(u32, fhandle) __field(u64, fileid) - __string(dstaddr, clp ? - rpc_peeraddr2str(clp->cl_rpcclient, - RPC_DISPLAY_ADDR) : "unknown") + __string(dstaddr, clp ? clp->cl_hostname : "unknown") ),

TP_fast_assign( @@ -1118,9 +1112,7 @@ DECLARE_EVENT_CLASS(nfs4_inode_callback_ __entry->fileid = 0; __entry->dev = 0; } - __assign_str(dstaddr, clp ? - rpc_peeraddr2str(clp->cl_rpcclient, - RPC_DISPLAY_ADDR) : "unknown") + __assign_str(dstaddr, clp ? clp->cl_hostname : "unknown") ),

TP_printk( @@ -1162,9 +1154,7 @@ DECLARE_EVENT_CLASS(nfs4_inode_stateid_c __field(dev_t, dev) __field(u32, fhandle) __field(u64, fileid) - __string(dstaddr, clp ? - rpc_peeraddr2str(clp->cl_rpcclient, - RPC_DISPLAY_ADDR) : "unknown") + __string(dstaddr, clp ? clp->cl_hostname : "unknown") __field(int, stateid_seq) __field(u32, stateid_hash) ), @@ -1179,9 +1169,7 @@ DECLARE_EVENT_CLASS(nfs4_inode_stateid_c __entry->fileid = 0; __entry->dev = 0; } - __assign_str(dstaddr, clp ? - rpc_peeraddr2str(clp->cl_rpcclient, - RPC_DISPLAY_ADDR) : "unknown") + __assign_str(dstaddr, clp ? clp->cl_hostname : "unknown") __entry->stateid_seq = be32_to_cpu(stateid->seqid); __entry->stateid_hash =

Patches currently in stable-queue which might be from Anna.Schumaker@Netapp.com are

queue-4.9/nfs-avoid-rcu-usage-in-tracepoints.patch queue-4.9/nfs-fix-ugly-referral-attributes.patch queue-4.9/nfs-fix-typo-in-nomigration-mount-option.patch