lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 19 Mar 2015 15:35:49 -0700
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Sachin Prabhu <sprabhu@...hat.com>,
	Jeff Layton <jlayton@...ba.org>,
	Steve French <steve.french@...marydata.com>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 3.13.y-ckt 61/80] Complete oplock break jobs before closing file handle

3.13.11-ckt17 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sachin Prabhu <sprabhu@...hat.com>

commit ca7df8e0bb2a5ec79691de8a1a4c0e611fe04e60 upstream.

Commit
c11f1df5003d534fd067f0168bfad7befffb3b5c
requires writers to wait for any pending oplock break handler to
complete before proceeding to write. This is done by waiting on bit
CIFS_INODE_PENDING_OPLOCK_BREAK in cifsFileInfo->flags. This bit is
cleared by the oplock break handler job queued on the workqueue once it
has completed handling the oplock break allowing writers to proceed with
writing to the file.

While testing, it was noticed that the filehandle could be closed while
there is a pending oplock break which results in the oplock break
handler on the cifsiod workqueue being cancelled before it has had a
chance to execute and clear the CIFS_INODE_PENDING_OPLOCK_BREAK bit.
Any subsequent attempt to write to this file hangs waiting for the
CIFS_INODE_PENDING_OPLOCK_BREAK bit to be cleared.

We fix this by ensuring that we also clear the bit
CIFS_INODE_PENDING_OPLOCK_BREAK when we remove the oplock break handler
from the workqueue.

The bug was found by Red Hat QA while testing using ltp's fsstress
command.

Signed-off-by: Sachin Prabhu <sprabhu@...hat.com>
Acked-by: Shirish Pargaonkar <shirishpargaonkar@...il.com>
Signed-off-by: Jeff Layton <jlayton@...ba.org>
Signed-off-by: Steve French <steve.french@...marydata.com>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 fs/cifs/file.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index e157583..3530d7c 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -366,6 +366,7 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
 	struct cifsLockInfo *li, *tmp;
 	struct cifs_fid fid;
 	struct cifs_pending_open open;
+	bool oplock_break_cancelled;
 
 	spin_lock(&cifs_file_list_lock);
 	if (--cifs_file->count > 0) {
@@ -397,7 +398,7 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
 	}
 	spin_unlock(&cifs_file_list_lock);
 
-	cancel_work_sync(&cifs_file->oplock_break);
+	oplock_break_cancelled = cancel_work_sync(&cifs_file->oplock_break);
 
 	if (!tcon->need_reconnect && !cifs_file->invalidHandle) {
 		struct TCP_Server_Info *server = tcon->ses->server;
@@ -409,6 +410,9 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
 		_free_xid(xid);
 	}
 
+	if (oplock_break_cancelled)
+		cifs_done_oplock_break(cifsi);
+
 	cifs_del_pending_open(&open);
 
 	/*
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists