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| author | Zheng Wang <zyytlz.wz@163.com> | 2023-03-13 22:43:25 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-04-20 12:10:25 +0200 |
| commit | 9266e939d76279d8710196d86215ba2be6345041 (patch) | |
| tree | fedc6769644435558d8a067bcdb835b5398bc62d | |
| parent | ae11498851423d6de27aebfe12a5ee85060ab1d5 (diff) | |
| download | linux-stable-9266e939d76279d8710196d86215ba2be6345041.tar.gz linux-stable-9266e939d76279d8710196d86215ba2be6345041.tar.bz2 linux-stable-9266e939d76279d8710196d86215ba2be6345041.zip | |
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 220e8f4ac0cf..da056170849b 100644 --- a/net/9p/trans_xen.c +++ b/net/9p/trans_xen.c @@ -300,6 +300,10 @@ 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) |