From: Davide Caratti dcaratti@redhat.com
[ Upstream commit 092e22e586236bba106a82113826a68080a03506 ]
Now that 'TCQ_F_CPUSTATS' bit can be cleared, depending on the value of 'TCQ_F_NOLOCK' bit in the parent qdisc, we can't assume anymore that per-cpu counters are there in the error path of skb_array_produce(). Otherwise, the following splat can be seen:
Unable to handle kernel paging request at virtual address 0000600dea430008 Mem abort info: ESR = 0x96000005 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000005 CM = 0, WnR = 0 user pgtable: 64k pages, 48-bit VAs, pgdp = 000000007b97530e [0000600dea430008] pgd=0000000000000000, pud=0000000000000000 Internal error: Oops: 96000005 [#1] SMP [...] pstate: 10000005 (nzcV daif -PAN -UAO) pc : pfifo_fast_enqueue+0x524/0x6e8 lr : pfifo_fast_enqueue+0x46c/0x6e8 sp : ffff800d39376fe0 x29: ffff800d39376fe0 x28: 1ffff001a07d1e40 x27: ffff800d03e8f188 x26: ffff800d03e8f200 x25: 0000000000000062 x24: ffff800d393772f0 x23: 0000000000000000 x22: 0000000000000403 x21: ffff800cca569a00 x20: ffff800d03e8ee00 x19: ffff800cca569a10 x18: 00000000000000bf x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: ffff1001a726edd0 x13: 1fffe4000276a9a4 x12: 0000000000000000 x11: dfff200000000000 x10: ffff800d03e8f1a0 x9 : 0000000000000003 x8 : 0000000000000000 x7 : 00000000f1f1f1f1 x6 : ffff1001a726edea x5 : ffff800cca56a53c x4 : 1ffff001bf9a8003 x3 : 1ffff001bf9a8003 x2 : 1ffff001a07d1dcb x1 : 0000600dea430000 x0 : 0000600dea430008 Process ping (pid: 6067, stack limit = 0x00000000dc0aa557) Call trace: pfifo_fast_enqueue+0x524/0x6e8 htb_enqueue+0x660/0x10e0 [sch_htb] __dev_queue_xmit+0x123c/0x2de0 dev_queue_xmit+0x24/0x30 ip_finish_output2+0xc48/0x1720 ip_finish_output+0x548/0x9d8 ip_output+0x334/0x788 ip_local_out+0x90/0x138 ip_send_skb+0x44/0x1d0 ip_push_pending_frames+0x5c/0x78 raw_sendmsg+0xed8/0x28d0 inet_sendmsg+0xc4/0x5c0 sock_sendmsg+0xac/0x108 __sys_sendto+0x1ac/0x2a0 __arm64_sys_sendto+0xc4/0x138 el0_svc_handler+0x13c/0x298 el0_svc+0x8/0xc Code: f9402e80 d538d081 91002000 8b010000 (885f7c03)
Fix this by testing the value of 'TCQ_F_CPUSTATS' bit in 'qdisc->flags', before dereferencing 'qdisc->cpu_qstats'.
Fixes: 8a53e616de29 ("net: sched: when clearing NOLOCK, clear TCQ_F_CPUSTATS, too") CC: Paolo Abeni pabeni@redhat.com CC: Stefano Brivio sbrivio@redhat.com Reported-by: Li Shuang shuali@redhat.com Signed-off-by: Davide Caratti dcaratti@redhat.com Acked-by: Paolo Abeni pabeni@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/sch_generic.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -624,8 +624,12 @@ static int pfifo_fast_enqueue(struct sk_
err = skb_array_produce(q, skb);
- if (unlikely(err)) - return qdisc_drop_cpu(skb, qdisc, to_free); + if (unlikely(err)) { + if (qdisc_is_percpu_stats(qdisc)) + return qdisc_drop_cpu(skb, qdisc, to_free); + else + return qdisc_drop(skb, qdisc, to_free); + }
qdisc_update_stats_at_enqueue(qdisc, pkt_len); return NET_XMIT_SUCCESS;