Hi Jakub Kicinski, Thanks for the feedback. > Subject: Re: [PATCH net-next v3 00/14] Add functional support for Gigabit > Ethernet driver > > On Tue, 12 Oct 2021 18:53:50 +0000 Biju Das wrote: > > > > Yes, you are correct. Sergey, suggested use R-Car RX-HW checksum > > > > with RCSC/RCPT and But the TOE gives either 0x0 or 0xffff as csum > > > > output and feeding this value to skb->csum lead to kernel crash. > > > > > > That's quite concerning. Do you have any of the > > > > > > /proc/sys/kernel/panic_on_io_nmi > > > /proc/sys/kernel/panic_on_oops > > > /proc/sys/kernel/panic_on_rcu_stall > > > /proc/sys/kernel/panic_on_unrecovered_nmi > > > /proc/sys/kernel/panic_on_warn > > > > > > knobs set? I'm guessing we hit do_netdev_rx_csum_fault() when the > > > checksum is incorrect, but I'm surprised that causes a panic. > > > > I tested this last week, if I remember correctly It was not panic, > > rather do_netdev_rx_csum_fault. I will recheck and will send you the > > stack trace next time. > > Ah, when you say crash you mean a stack trace appears. The machine does > not crash? That's fine, we don't need to see the trace. I have rechecked today. It does crash, if you pass bad checksum to skb->csum. Please find the logs. root@smarc-rzg2l:~# ethtool -K eth0 rx on Actual changes: rx-checksum: on [ 34.391956] eth0: hw csum failure [ 34.396044] skb len=168 headroom=142 headlen=168 tailroom=15754 [ 34.396044] mac=(128,14) net=(142,20) trans=162 [ 34.396044] shinfo(txflags=0 nr_frags=0 gso(size=0 type=0 segs=0)) [ 34.396044] csum(0x0 ip_summed=2 complete_sw=0 valid=0 level=0) [ 34.396044] hash(0x0 sw=0 l4=0) proto=0x0800 pkttype=0 iif=0 [ 34.425196] dev name=eth0 feat=0x0x0000010000004000 [ 34.430231] skb headroom: 00000000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 34.438064] skb headroom: 00000010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 34.445863] skb headroom: 00000020: ff ff ff ff ff ff ff ff ff ff ff fe ff ff ff ff [ 34.453660] skb headroom: 00000030: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 34.461453] skb headroom: 00000040: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff [ 34.469246] skb headroom: 00000050: ff ff ff ff ff fe ff ff ff ff ef ff ff ff ff ff [ 34.477038] skb headroom: 00000060: ff ff ff ff ff ff ff ff fd fe ff ff ff ff ff ff [ 34.484831] skb headroom: 00000070: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff f7 [ 34.492629] skb headroom: 00000080: 00 11 22 33 44 55 08 00 27 a0 90 eb 08 00 [ 34.499895] skb linear: 00000000: 45 00 00 a8 54 06 40 00 40 06 50 f6 c0 a8 0a 01 [ 34.507692] skb linear: 00000010: c0 a8 0a 02 08 01 03 0c 1d aa 76 e1 a3 4b 1c d8 [ 34.515488] skb linear: 00000020: 80 18 21 55 72 75 00 00 01 01 08 0a da da 94 96 [ 34.523283] skb linear: 00000030: b5 fb f1 40 80 00 00 70 d9 4a 86 c0 00 00 00 01 [ 34.531078] skb linear: 00000040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 34.538873] skb linear: 00000050: 00 00 00 00 00 00 00 05 00 00 01 ff 00 00 00 01 [ 34.546668] skb linear: 00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 11 [ 34.554462] skb linear: 00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 34.562260] skb linear: 00000080: 58 9d 6c 79 80 e3 86 f2 00 00 00 00 00 9a 8d 38 [ 34.570055] skb linear: 00000090: 61 65 87 ee 22 8c 2f b9 61 4a 17 fb 35 09 00 98 [ 34.577850] skb linear: 000000a0: 61 4a 17 fb 35 09 00 98 [ 34.583534] skb tailroom: 00000000: 00 00 00 00 21 07 00 b0 63 70 47 f9 42 5f 47 f9 [ 34.591329] skb tailroom: 00000010: 21 f8 47 f9 80 74 47 f9 de 60 fc 97 a0 06 00 f9 [ 42.262329] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.15.0-rc4-arm64-renesas-01223-g75a50e114cb6-dirty #416 [ 42.272370] Hardware name: Renesas SMARC EVK based on r9a07g044l2 (DT) [ 42.278979] Call trace: [ 42.281460] dump_backtrace+0x0/0x188 [ 42.285186] show_stack+0x14/0x20 [ 42.288550] dump_stack_lvl+0x88/0xb0 [ 42.292267] dump_stack+0x14/0x2c [ 42.295629] do_netdev_rx_csum_fault+0x44/0x50 [ 42.300134] __skb_gro_checksum_complete+0xb0/0xb8 [ 42.304994] tcp4_gro_receive+0xbc/0x198 [ 42.308974] inet_gro_receive+0x300/0x410 [ 42.313039] dev_gro_receive+0x308/0x898 [ 42.317018] napi_gro_receive+0x88/0x370 [ 42.320996] ravb_rx_gbeth+0x36c/0x568 [ 42.324801] ravb_poll+0xd0/0x278 [ 42.328163] __napi_poll+0x38/0x2e0 [ 42.331702] net_rx_action+0xf4/0x248 [ 42.335416] _stext+0x150/0x5d8 [ 42.338604] irq_exit+0x198/0x1b8 [ 42.341970] handle_domain_irq+0x60/0x88 [ 42.345950] gic_handle_irq+0x50/0x110 [ 42.349755] call_on_irq_stack+0x28/0x3c [ 42.353733] do_interrupt_handler+0x4c/0x58 [ 42.357974] el1_interrupt+0x2c/0x108 [ 42.361688] el1h_64_irq_handler+0x14/0x20 [ 42.365841] el1h_64_irq+0x74/0x78 [ 42.369291] arch_cpu_idle+0x14/0x20 [ 42.372918] default_idle_call+0x78/0x330 [ 42.376984] do_idle+0x22c/0x278 [ 42.380261] cpu_startup_entry+0x20/0x68 [ 42.384239] rest_init+0x180/0x280 [ 42.387689] arch_call_rest_init+0xc/0x14 [ 42.391759] start_kernel+0x62c/0x664 [ 42.395472] __primary_switched+0xa0/0xa8 Regards, Biju
