The patch titled
nbd: prevent sock_xmit from attempting to use a NULL socket
has been added to the -mm tree. Its filename is
nbd-prevent-sock_xmit-from-attempting-to-use-a-null-socket.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: nbd: prevent sock_xmit from attempting to use a NULL socket
From: Mike Snitzer <snitzer@xxxxxxxxx>
NBD does not protect the nbd_device's socket from becoming NULL during
receives.
This closes a race with the NBD_CLEAR_SOCK ioctl (nbd-client -d) setting
the nbd_device's socket to NULL right before NBD calls sock_xmit.
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxx>
Cc: Paul Clements <paul.clements@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/nbd.c | 6 ++++++
1 file changed, 6 insertions(+)
diff -puN drivers/block/nbd.c~nbd-prevent-sock_xmit-from-attempting-to-use-a-null-socket drivers/block/nbd.c
--- a/drivers/block/nbd.c~nbd-prevent-sock_xmit-from-attempting-to-use-a-null-socket
+++ a/drivers/block/nbd.c
@@ -153,6 +153,12 @@ static int sock_xmit(struct nbd_device *
struct kvec iov;
sigset_t blocked, oldset;
+ if (unlikely(!sock)) {
+ printk(KERN_ERR "%s: Attempted %s on closed socket in sock_xmit\n",
+ lo->disk->disk_name, (send ? "send" : "recv"));
+ return -EINVAL;
+ }
+
/* Allow interception of SIGKILL only
* Don't allow other signals to interrupt the transmission */
siginitsetinv(&blocked, sigmask(SIGKILL));
_
Patches currently in -mm which might be from snitzer@xxxxxxxxx are
percpu-__percpu_alloc_mask-can-dynamically-size-percpu_data-storage.patch
nbd-prevent-sock_xmit-from-attempting-to-use-a-null-socket.patch
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