Patch "uml: fix hostfs mknod()" has been added to the 3.10-stable tree

[<gregkh@linuxfoundation.org>]

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

    uml: fix hostfs mknod()

to the 3.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     uml-fix-hostfs-mknod.patch
and it can be found in the queue-3.10 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 9f2dfda2f2f1c6181c3732c16b85c59ab2d195e0 Mon Sep 17 00:00:00 2001
From: Vegard Nossum <vegard.nossum@oracle.com>
Date: Wed, 16 Dec 2015 21:59:56 +0100
Subject: uml: fix hostfs mknod()

From: Vegard Nossum <vegard.nossum@oracle.com>

commit 9f2dfda2f2f1c6181c3732c16b85c59ab2d195e0 upstream.

An inverted return value check in hostfs_mknod() caused the function
to return success after handling it as an error (and cleaning up).

It resulted in the following segfault when trying to bind() a named
unix socket:

  Pid: 198, comm: a.out Not tainted 4.4.0-rc4
  RIP: 0033:[<0000000061077df6>]
  RSP: 00000000daae5d60  EFLAGS: 00010202
  RAX: 0000000000000000 RBX: 000000006092a460 RCX: 00000000dfc54208
  RDX: 0000000061073ef1 RSI: 0000000000000070 RDI: 00000000e027d600
  RBP: 00000000daae5de0 R08: 00000000da980ac0 R09: 0000000000000000
  R10: 0000000000000003 R11: 00007fb1ae08f72a R12: 0000000000000000
  R13: 000000006092a460 R14: 00000000daaa97c0 R15: 00000000daaa9a88
  Kernel panic - not syncing: Kernel mode fault at addr 0x40, ip 0x61077df6
  CPU: 0 PID: 198 Comm: a.out Not tainted 4.4.0-rc4 #1
  Stack:
   e027d620 dfc54208 0000006f da981398
   61bee000 0000c1ed daae5de0 0000006e
   e027d620 dfcd4208 00000005 6092a460
  Call Trace:
   [<60dedc67>] SyS_bind+0xf7/0x110
   [<600587be>] handle_syscall+0x7e/0x80
   [<60066ad7>] userspace+0x3e7/0x4e0
   [<6006321f>] ? save_registers+0x1f/0x40
   [<6006c88e>] ? arch_prctl+0x1be/0x1f0
   [<60054985>] fork_handler+0x85/0x90

Let's also get rid of the "cosmic ray protection" while we're at it.

Fixes: e9193059b1b3 "hostfs: fix races in dentry_name() and inode_name()"
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/hostfs/hostfs_kern.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -720,15 +720,13 @@ static int hostfs_mknod(struct inode *di
 
 	init_special_inode(inode, mode, dev);
 	err = do_mknod(name, mode, MAJOR(dev), MINOR(dev));
-	if (!err)
+	if (err)
 		goto out_free;
 
 	err = read_name(inode, name);
 	__putname(name);
 	if (err)
 		goto out_put;
-	if (err)
-		goto out_put;
 
 	d_instantiate(dentry, inode);
 	return 0;


Patches currently in stable-queue which might be from vegard.nossum@oracle.com are

queue-3.10/uml-flush-stdout-before-forking.patch
queue-3.10/rds-fix-race-condition-when-sending-a-message-on-unbound-socket.patch
queue-3.10/uml-fix-hostfs-mknod.patch