[PATCH net 1/5] ppp: lock ppp structure before modifying mru in ppp_ioctl()

[Guillaume Nault]

PPP's Tx and Rx paths read ppp->mru under protection of ppp_xmit_lock()
and ppp_recv_lock() respectively.
Therefore ppp_ioctl() must hold the xmit and recv locks before
concurrently updating ppp->mru.

Signed-off-by: Guillaume Nault <g.na...@alphalink.fr>
---
 drivers/net/ppp/ppp_generic.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index fc8ad00..4d342ae 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -654,7 +654,10 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, 
unsigned long arg)
        case PPPIOCSMRU:
                if (get_user(val, p))
                        break;
+               ppp_lock(ppp);
                ppp->mru = val;
+               ppp_unlock(ppp);
+
                err = 0;
                break;
 
-- 
2.7.0