tree 25b802756e24a49a1d1770465495ec6eee1ba381
parent b82eaa2815935d4326d5042e27f08498176f31dd
author Ronnie Sahlberg <lsahlber@redhat.com> 1544652376 +1000
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1549997098 +0100

cifs: check ntwrk_buf_start for NULL before dereferencing it

[ Upstream commit 59a63e479ce36a3f24444c3a36efe82b78e4a8e0 ]

RHBZ: 1021460

There is an issue where when multiple threads open/close the same directory
ntwrk_buf_start might end up being NULL, causing the call to smbCalcSize
later to oops with a NULL deref.

The real bug is why this happens and why this can become NULL for an
open cfile, which should not be allowed.
This patch tries to avoid a oops until the time when we fix the underlying
issue.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>