This is a note to let you know that I've just added the patch titled
nfs: Don't take a reference on fl->fl_file for LOCK operation
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-don-t-take-a-reference-on-fl-fl_file-for-lock-operation.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 foo@baz Wed Dec 6 17:39:55 CET 2017
From: Benjamin Coddington bcodding@redhat.com Date: Thu, 5 Jan 2017 10:20:16 -0500 Subject: nfs: Don't take a reference on fl->fl_file for LOCK operation
From: Benjamin Coddington bcodding@redhat.com
[ Upstream commit 4b09ec4b14a168bf2c687e1f598140c3c11e9222 ]
I have reports of a crash that look like __fput() was called twice for a NFSv4.0 file. It seems possible that the state manager could try to reclaim a lock and take a reference on the fl->fl_file at the same time the file is being released if, during the close(), a signal interrupts the wait for outstanding IO while removing locks which then skips the removal of that lock.
Since 83bfff23e9ed ("nfs4: have do_vfs_lock take an inode pointer") has removed the need to traverse fl->fl_file->f_inode in nfs4_lock_done(), taking that reference is no longer necessary.
Signed-off-by: Benjamin Coddington bcodding@redhat.com Reviewed-by: Jeff Layton jlayton@redhat.com Signed-off-by: Trond Myklebust trond.myklebust@primarydata.com Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfs/nfs4proc.c | 3 --- 1 file changed, 3 deletions(-)
--- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -38,7 +38,6 @@ #include <linux/mm.h> #include <linux/delay.h> #include <linux/errno.h> -#include <linux/file.h> #include <linux/string.h> #include <linux/ratelimit.h> #include <linux/printk.h> @@ -6006,7 +6005,6 @@ static struct nfs4_lockdata *nfs4_alloc_ p->server = server; atomic_inc(&lsp->ls_count); p->ctx = get_nfs_open_context(ctx); - get_file(fl->fl_file); memcpy(&p->fl, fl, sizeof(p->fl)); return p; out_free_seqid: @@ -6119,7 +6117,6 @@ static void nfs4_lock_release(void *call nfs_free_seqid(data->arg.lock_seqid); nfs4_put_lock_state(data->lsp); put_nfs_open_context(data->ctx); - fput(data->fl.fl_file); kfree(data); dprintk("%s: done!\n", __func__); }
Patches currently in stable-queue which might be from bcodding@redhat.com are
queue-4.9/nfs-don-t-take-a-reference-on-fl-fl_file-for-lock-operation.patch