[PATCH 6.8 040/158] tun: limit printing rate when illegal packet received by tun dev

Greg Kroah-Hartman
2024-04-23T21:41:13Z

From: Lei Chen <lei.chen@smartx.com>

[ Upstream commit f8bbc07ac535593139c875ffa19af924b1084540 ]

vhost_worker will call tun call backs to receive packets. If too many
illegal packets arrives, tun_do_read will keep dumping packet contents.
When console is enabled, it will costs much more cpu time to dump
packet and soft lockup will be detected.

net_ratelimit mechanism can be used to limit the dumping rate.

PID: 33036 TASK: ffff949da6f20000 CPU: 23 COMMAND: "vhost-32980"
#0 [fffffe00003fce50] crash_nmi_callback at ffffffff89249253
#1 [fffffe00003fce58] nmi_handle at ffffffff89225fa3
#2 [fffffe00003fceb0] default_do_nmi at ffffffff8922642e
#3 [fffffe00003fced0] do_nmi at ffffffff8922660d
#4 [fffffe00003fcef0] end_repeat_nmi at ffffffff89c01663
[exception RIP: io_serial_in+20]
RIP: ffffffff89792594 RSP: ffffa655314979e8 RFLAGS: 00000002
RAX: ffffffff89792500 RBX: ffffffff8af428a0 RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000005 RDI: ffffffff8af428a0
RBP: 0000000000002710 R8: 0000000000000004 R9: 000000000000000f
R10: 0000000000000000 R11: ffffffff8acbf64f R12: 0000000000000020
R13: ffffffff8acbf698 R14: 0000000000000058 R15: 0000000000000000
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#5 [ffffa655314979e8] io_serial_in at ffffffff89792594
#6 [ffffa655314979e8] wait_for_xmitr at ffffffff89793470
#7 [ffffa65531497a08] serial8250_console_putchar at ffffffff897934f6
#8 [ffffa65531497a20] uart_console_write at ffffffff8978b605
#9 [ffffa65531497a48] serial8250_console_write at ffffffff89796558
#10 [ffffa65531497ac8] console_unlock at ffffffff89316124
#11 [ffffa65531497b10] vprintk_emit at ffffffff89317c07
#12 [ffffa65531497b68] printk at ffffffff89318306
#13 [ffffa65531497bc8] print_hex_dump at ffffffff89650765
#14 [ffffa65531497ca8] tun_do_read at ffffffffc0b06c27 [tun]
#15 [ffffa65531497d38] tun_recvmsg at ffffffffc0b06e34 [tun]
#16 [ffffa65531497d68] handle_rx at ffffffffc0c5d682 [vhost_net]
#17 [ffffa65531497ed0] vhost_worker at ffffffffc0c644dc [vhost]
#18 [ffffa65531497f10] kthread at ffffffff892d2e72
#19 [ffffa65531497f50] ret_from_fork at ffffffff89c0022f

Fixes: ef3db4a59542 ("tun: avoid BUG, dump packet on GSO errors")
Signed-off-by: Lei Chen <lei.chen@smartx.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20240415020247.2207781-1-lei.chen@smartx.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/tun.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 8f95a562b8d0c..86515f0c2b6c1 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -2132,14 +2132,16 @@ static ssize_t tun_put_user(struct tun_struct *tun,
tun_is_little_endian(tun), true,
vlan_hlen)) {
struct skb_shared_info *sinfo = skb_shinfo(skb);
- pr_err("unexpected GSO type: "
- "0x%x, gso_size %d, hdr_len %d\n",
- sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
- tun16_to_cpu(tun, gso.hdr_len));
- print_hex_dump(KERN_ERR, "tun: ",
- DUMP_PREFIX_NONE,
- 16, 1, skb->head,
- min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
+
+ if (net_ratelimit()) {
+ netdev_err(tun->dev, "unexpected GSO type: 0x%x, gso_size %d, hdr_len %d\n",
+ sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
+ tun16_to_cpu(tun, gso.hdr_len));
+ print_hex_dump(KERN_ERR, "tun: ",
+ DUMP_PREFIX_NONE,
+ 16, 1, skb->head,
+ min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
+ }
WARN_ON_ONCE(1);
return -EINVAL;
}
--
2.43.0