This is a note to let you know that I've just added the patch titled
net: sched: cake: fix null pointer access issue when cake_init() fails
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-sched-cake-fix-null-pointer-access-issue-when-ca.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1f4d25ad81cae5cc01f9c96c9ebcd5d7a890292f
Author: Zhengchao Shao <shaozhengchao@xxxxxxxxxx>
Date: Tue Oct 18 14:31:59 2022 +0800
net: sched: cake: fix null pointer access issue when cake_init() fails
[ Upstream commit 51f9a8921ceacd7bf0d3f47fa867a64988ba1dcb ]
When the default qdisc is cake, if the qdisc of dev_queue fails to be
inited during mqprio_init(), cake_reset() is invoked to clear
resources. In this case, the tins is NULL, and it will cause gpf issue.
The process is as follows:
qdisc_create_dflt()
cake_init()
q->tins = kvcalloc(...) --->failed, q->tins is NULL
...
qdisc_put()
...
cake_reset()
...
cake_dequeue_one()
b = &q->tins[...] --->q->tins is NULL
The following is the Call Trace information:
general protection fault, probably for non-canonical address
0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:cake_dequeue_one+0xc9/0x3c0
Call Trace:
<TASK>
cake_reset+0xb1/0x140
qdisc_reset+0xed/0x6f0
qdisc_destroy+0x82/0x4c0
qdisc_put+0x9e/0xb0
qdisc_create_dflt+0x2c3/0x4a0
mqprio_init+0xa71/0x1760
qdisc_create+0x3eb/0x1000
tc_modify_qdisc+0x408/0x1720
rtnetlink_rcv_msg+0x38e/0xac0
netlink_rcv_skb+0x12d/0x3a0
netlink_unicast+0x4a2/0x740
netlink_sendmsg+0x826/0xcc0
sock_sendmsg+0xc5/0x100
____sys_sendmsg+0x583/0x690
___sys_sendmsg+0xe8/0x160
__sys_sendmsg+0xbf/0x160
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f89e5122d04
</TASK>
Fixes: 046f6fd5daef ("sched: Add Common Applications Kept Enhanced (cake) qdisc")
Signed-off-by: Zhengchao Shao <shaozhengchao@xxxxxxxxxx>
Acked-by: Toke Høiland-Jørgensen <toke@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c
index c580139fcede..5dc7a3c310c9 100644
--- a/net/sched/sch_cake.c
+++ b/net/sched/sch_cake.c
@@ -2224,8 +2224,12 @@ static struct sk_buff *cake_dequeue(struct Qdisc *sch)
static void cake_reset(struct Qdisc *sch)
{
+ struct cake_sched_data *q = qdisc_priv(sch);
u32 c;
+ if (!q->tins)
+ return;
+
for (c = 0; c < CAKE_MAX_TINS; c++)
cake_clear_tin(sch, c);
}
