diff options
| author | Zheng Wang <zyytlz.wz@163.com> | 2023-03-13 22:43:25 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-04-20 12:04:40 +0200 |
| commit | c078fcd3f00ea5eadad07da169956d84f65af49b (patch) | |
| tree | 12ab657a424a26235c49ce54feca488a66c0316a | |
| parent | 92fd37e0f03f57b5ff404077de36a3d5b263ad98 (diff) | |
9p/xen : Fix use after free bug in xen_9pfs_front_remove due to race condition
[ Upstream commit ea4f1009408efb4989a0f139b70fb338e7f687d0 ]
In xen_9pfs_front_probe, it calls xen_9pfs_front_alloc_dataring
to init priv->rings and bound &ring->work with p9_xen_response.
When it calls xen_9pfs_front_event_handler to handle IRQ requests,
it will finally call schedule_work to start the work.
When we call xen_9pfs_front_remove to remove the driver, there
may be a sequence as follows:
Fix it by finishing the work before cleanup in xen_9pfs_front_free.
Note that, this bug is found by static analysis, which might be
false positive.
CPU0 CPU1
|p9_xen_response
xen_9pfs_front_remove|
xen_9pfs_front_free|
kfree(priv) |
//free priv |
|p9_tag_lookup
|//use priv->client
Fixes: 71ebd71921e4 ("xen/9pfs: connect to the backend")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | net/9p/trans_xen.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c index 08b96aeaff46..c87146a49636 100644 --- a/net/9p/trans_xen.c +++ b/net/9p/trans_xen.c @@ -299,6 +299,10 @@ static void xen_9pfs_front_free(struct xen_9pfs_front_priv *priv) write_unlock(&xen_9pfs_lock); for (i = 0; i < priv->num_rings; i++) { + struct xen_9pfs_dataring *ring = &priv->rings[i]; + + cancel_work_sync(&ring->work); + if (!priv->rings[i].intf) break; if (priv->rings[i].irq > 0) |