Subject: Re: [PATCH net v2 1/3] igc: Clean the TX buffer and TX descriptor ring

From: Maciej Fijalkowski <[email-masked]>
Date: Fri, 9 Jun 2023 18:20:29 +0200

On Fri, Jun 09, 2023 at 09:10:56AM -0700, Tony Nguyen wrote:
> From: Muhammad Husaini Zulkifli <[email-masked]>
> 
> There could be a race condition during link down where interrupt
> being generated and igc_clean_tx_irq() been called to perform the
> TX completion. Properly clear the TX buffer/descriptor ring and
> disable the TX Queue ring in igc_free_tx_resources() to avoid that.
> 
> Kernel trace:
> [  108.237177] Hardware name: Intel Corporation Tiger Lake Client Platform/TigerLake U DDR4 SODIMM RVP, BIOS TGLIFUI1.R00.4204.A00.2105270302 05/27/2021
> [  108.237178] RIP: 0010:refcount_warn_saturate+0x55/0x110
> [  108.242143] RSP: 0018:ffff9e7980003db0 EFLAGS: 00010286
> [  108.245555] Code: 84 bc 00 00 00 c3 cc cc cc cc 85 f6 74 46 80 3d 20 8c 4d 01 00 75 ee 48 c7 c7 88 f4 03 ab c6 05 10 8c 4d 01 01 e8 0b 10 96 ff <0f> 0b c3 cc cc cc cc 80 3d fc 8b 4d 01 00 75 cb 48 c7 c7 b0 f4 03
> [  108.250434]
> [  108.250434] RSP: 0018:ffff9e798125f910 EFLAGS: 00010286
> [  108.254358] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
> [  108.259325]
> [  108.259325] RAX: 0000000000000000 RBX: ffff8ddb935b8000 RCX: 0000000000000027
> [  108.261868] RDX: ffff8de250a28800 RSI: ffff8de250a1c580 RDI: ffff8de250a1c580
> [  108.265538] RDX: 0000000000000027 RSI: 0000000000000002 RDI: ffff8de250a9c588
> [  108.265539] RBP: ffff8ddb935b8000 R08: ffffffffab2655a0 R09: ffff9e798125f898
> [  108.267914] RBP: ffff8ddb8a5b8d80 R08: 0000005648eba354 R09: 0000000000000000
> [  108.270196] R10: 0000000000000001 R11: 000000002d2d2d2d R12: ffff9e798125f948
> [  108.270197] R13: ffff9e798125fa1c R14: ffff8ddb8a5b8d80 R15: 7fffffffffffffff
> [  108.273001] R10: 000000002d2d2d2d R11: 000000002d2d2d2d R12: ffff8ddb8a5b8ed4
> [  108.276410] FS:  00007f605851b740(0000) GS:ffff8de250a80000(0000) knlGS:0000000000000000
> [  108.280597] R13: 00000000000002ac R14: 00000000ffffff99 R15: ffff8ddb92561b80
> [  108.282966] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  108.282967] CR2: 00007f053c039248 CR3: 0000000185850003 CR4: 0000000000f70ee0
> [  108.286206] FS:  0000000000000000(0000) GS:ffff8de250a00000(0000) knlGS:0000000000000000
> [  108.289701] PKRU: 55555554
> [  108.289702] Call Trace:
> [  108.289704]  <TASK>
> [  108.293977] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  108.297562]  sock_alloc_send_pskb+0x20c/0x240
> [  108.301494] CR2: 00007f053c03a168 CR3: 0000000184394002 CR4: 0000000000f70ef0
> [  108.301495] PKRU: 55555554
> [  108.306464]  __ip_append_data.isra.0+0x96f/0x1040
> [  108.309441] Call Trace:
> [  108.309443]  ? __pfx_ip_generic_getfrag+0x10/0x10
> [  108.314927]  <IRQ>
> [  108.314928]  sock_wfree+0x1c7/0x1d0
> [  108.318078]  ? __pfx_ip_generic_getfrag+0x10/0x10
> [  108.320276]  skb_release_head_state+0x32/0x90
> [  108.324812]  ip_make_skb+0xf6/0x130
> [  108.327188]  skb_release_all+0x16/0x40
> [  108.330775]  ? udp_sendmsg+0x9f3/0xcb0
> [  108.332626]  napi_consume_skb+0x48/0xf0
> [  108.334134]  ? xfrm_lookup_route+0x23/0xb0
> [  108.344285]  igc_poll+0x787/0x1620 [igc]
> [  108.346659]  udp_sendmsg+0x9f3/0xcb0
> [  108.360010]  ? ttwu_do_activate+0x40/0x220
> [  108.365237]  ? __pfx_ip_generic_getfrag+0x10/0x10
> [  108.366744]  ? try_to_wake_up+0x289/0x5e0
> [  108.376987]  ? sock_sendmsg+0x81/0x90
> [  108.395698]  ? __pfx_process_timeout+0x10/0x10
> [  108.395701]  sock_sendmsg+0x81/0x90
> [  108.409052]  __napi_poll+0x29/0x1c0
> [  108.414279]  ____sys_sendmsg+0x284/0x310
> [  108.419507]  net_rx_action+0x257/0x2d0
> [  108.438216]  ___sys_sendmsg+0x7c/0xc0
> [  108.439723]  __do_softirq+0xc1/0x2a8
> [  108.444950]  ? finish_task_switch+0xb4/0x2f0
> [  108.452077]  irq_exit_rcu+0xa9/0xd0
> [  108.453584]  ? __schedule+0x372/0xd00
> [  108.460713]  common_interrupt+0x84/0xa0
> [  108.467840]  ? clockevents_program_event+0x95/0x100
> [  108.474968]  </IRQ>
> [  108.482096]  ? do_nanosleep+0x88/0x130
> [  108.489224]  <TASK>
> [  108.489225]  asm_common_interrupt+0x26/0x40
> [  108.496353]  ? __rseq_handle_notify_resume+0xa9/0x4f0
> [  108.503478] RIP: 0010:cpu_idle_poll+0x2c/0x100
> [  108.510607]  __sys_sendmsg+0x5d/0xb0
> [  108.518687] Code: 05 e1 d9 c8 00 65 8b 15 de 64 85 55 85 c0 7f 57 e8 b9 ef ff ff fb 65 48 8b 1c 25 00 cc 02 00 48 8b 03 a8 08 74 0b eb 1c f3 90 <48> 8b 03 a8 08 75 13 8b 05 77 63 cd 00 85 c0 75 ed e8 ce ec ff ff
> [  108.525817]  do_syscall_64+0x44/0xa0
> [  108.531563] RSP: 0018:ffffffffab203e70 EFLAGS: 00000202
> [  108.538693]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
> [  108.546775]
> [  108.546777] RIP: 0033:0x7f605862b7f7
> [  108.549495] RAX: 0000000000000001 RBX: ffffffffab20c940 RCX: 000000000000003b
> [  108.551955] Code: 0e 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10
> [  108.554068] RDX: 4000000000000000 RSI: 000000002da97f6a RDI: 00000000002b8ff4
> [  108.559816] RSP: 002b:00007ffc99264058 EFLAGS: 00000246
> [  108.564178] RBP: 0000000000000000 R08: 00000000002b8ff4 R09: ffff8ddb01554c80
> [  108.571302]  ORIG_RAX: 000000000000002e
> [  108.571303] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f605862b7f7
> [  108.574023] R10: 000000000000015b R11: 000000000000000f R12: ffffffffab20c940
> [  108.574024] R13: 0000000000000000 R14: ffff8de26fbeef40 R15: ffffffffab20c940
> [  108.578727] RDX: 0000000000000000 RSI: 00007ffc992640a0 RDI: 0000000000000003
> [  108.578728] RBP: 00007ffc99264110 R08: 0000000000000000 R09: 175f48ad1c3a9c00
> [  108.581187]  do_idle+0x62/0x230
> [  108.585890] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc992642d8
> [  108.585891] R13: 00005577814ab2ba R14: 00005577814addf0 R15: 00007f605876d000
> [  108.587920]  cpu_startup_entry+0x1d/0x20
> [  108.591422]  </TASK>
> [  108.596127]  rest_init+0xc5/0xd0
> [  108.600490] ---[ end trace 0000000000000000 ]---
> 
> Test Setup:
> 
> DUT:
> - Change mac address on DUT Side. Ensure NIC not having same MAC Address
> - Running udp_tai on DUT side. Let udp_tai running throughout the test
> 
> Example:
> ./udp_tai -i enp170s0 -P 100000 -p 90 -c 1 -t 0 -u 30004
> 
> Host:
> - Perform link up/down every 5 second.
> 
> Result:
> Kernel panic will happen on DUT Side.
> 
> Fixes: 13b5b7fd6a4a ("igc: Add support for Tx/Rx rings")
> Signed-off-by: Muhammad Husaini Zulkifli <[email-masked]>
> Tested-by: Naama Meir <[email-masked]>
> Signed-off-by: Tony Nguyen <[email-masked]>

Hmm i thought i was giving my rev-by tag...anyways:

Reviewed-by: Maciej Fijalkowski <[email-masked]>

> ---
>  drivers/net/ethernet/intel/igc/igc_main.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
> index 1c4676882082..f986e88be5c1 100644
> --- a/drivers/net/ethernet/intel/igc/igc_main.c
> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
> @@ -254,6 +254,13 @@ static void igc_clean_tx_ring(struct igc_ring *tx_ring)
>  	/* reset BQL for queue */
>  	netdev_tx_reset_queue(txring_txq(tx_ring));
>  
> +	/* Zero out the buffer ring */
> +	memset(tx_ring->tx_buffer_info, 0,
> +	       sizeof(*tx_ring->tx_buffer_info) * tx_ring->count);
> +
> +	/* Zero out the descriptor ring */
> +	memset(tx_ring->desc, 0, tx_ring->size);
> +
>  	/* reset next_to_use and next_to_clean */
>  	tx_ring->next_to_use = 0;
>  	tx_ring->next_to_clean = 0;
> @@ -267,7 +274,7 @@ static void igc_clean_tx_ring(struct igc_ring *tx_ring)
>   */
>  void igc_free_tx_resources(struct igc_ring *tx_ring)
>  {
> -	igc_clean_tx_ring(tx_ring);
> +	igc_disable_tx_ring(tx_ring);
>  
>  	vfree(tx_ring->tx_buffer_info);
>  	tx_ring->tx_buffer_info = NULL;
> -- 
> 2.38.1
>