Subject: [net 11/17] net/mlx5e: Track xmit submission to PTP WQ after populating metadata map

From: Saeed Mahameed <[email-masked]>
Date: Mon, 13 Nov 2023 13:08:20 -0800

From: Rahul Rameshbabu <[email-masked]>

Ensure the skb is available in metadata mapping to skbs before tracking the
metadata index for detecting undelivered CQEs. If the metadata index is put
in the tracking list before putting the skb in the map, the metadata index
might be used for detecting undelivered CQEs before the relevant skb is
available in the map, which can lead to a null-ptr-deref.

Log:
    general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN
    KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
    CPU: 0 PID: 1243 Comm: kworker/0:2 Not tainted 6.6.0-rc4+ #108
    Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
    Workqueue: events mlx5e_rx_dim_work [mlx5_core]
    RIP: 0010:mlx5e_ptp_napi_poll+0x9a4/0x2290 [mlx5_core]
    Code: 8c 24 38 cc ff ff 4c 8d 3c c1 4c 89 f9 48 c1 e9 03 42 80 3c 31 00 0f 85 97 0f 00 00 4d 8b 3f 49 8d 7f 28 48 89 f9 48 c1 e9 03 <42> 80 3c 31 00 0f 85 8b 0f 00 00 49 8b 47 28 48 85 c0 0f 84 05 07
    RSP: 0018:ffff8884d3c09c88 EFLAGS: 00010206
    RAX: 0000000000000069 RBX: ffff8881160349d8 RCX: 0000000000000005
    RDX: ffffed10218f48cf RSI: 0000000000000004 RDI: 0000000000000028
    RBP: ffff888122707700 R08: 0000000000000001 R09: ffffed109a781383
    R10: 0000000000000003 R11: 0000000000000003 R12: ffff88810c7a7a40
    R13: ffff888122707700 R14: dffffc0000000000 R15: 0000000000000000
    FS:  0000000000000000(0000) GS:ffff8884d3c00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 00007f4f878dd6e0 CR3: 000000014d108002 CR4: 0000000000370eb0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
    Call Trace:
    <IRQ>
    ? die_addr+0x3c/0xa0
    ? exc_general_protection+0x144/0x210
    ? asm_exc_general_protection+0x22/0x30
    ? mlx5e_ptp_napi_poll+0x9a4/0x2290 [mlx5_core]
    ? mlx5e_ptp_napi_poll+0x8f6/0x2290 [mlx5_core]
    __napi_poll.constprop.0+0xa4/0x580
    net_rx_action+0x460/0xb80
    ? _raw_spin_unlock_irqrestore+0x32/0x60
    ? __napi_poll.constprop.0+0x580/0x580
    ? tasklet_action_common.isra.0+0x2ef/0x760
    __do_softirq+0x26c/0x827
    irq_exit_rcu+0xc2/0x100
    common_interrupt+0x7f/0xa0
    </IRQ>
    <TASK>
    asm_common_interrupt+0x22/0x40
    RIP: 0010:__kmem_cache_alloc_node+0xb/0x330
    Code: 41 5d 41 5e 41 5f c3 8b 44 24 14 8b 4c 24 10 09 c8 eb d5 e8 b7 43 ca 01 0f 1f 80 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 57 <41> 56 41 89 d6 41 55 41 89 f5 41 54 49 89 fc 53 48 83 e4 f0 48 83
    RSP: 0018:ffff88812c4079c0 EFLAGS: 00000246
    RAX: 1ffffffff083c7fe RBX: ffff888100042dc0 RCX: 0000000000000218
    RDX: 00000000ffffffff RSI: 0000000000000dc0 RDI: ffff888100042dc0
    RBP: ffff88812c4079c8 R08: ffffffffa0289f96 R09: ffffed1025880ea9
    R10: ffff888138839f80 R11: 0000000000000002 R12: 0000000000000dc0
    R13: 0000000000000100 R14: 000000000000008c R15: ffff8881271fc450
    ? cmd_exec+0x796/0x2200 [mlx5_core]
    kmalloc_trace+0x26/0xc0
    cmd_exec+0x796/0x2200 [mlx5_core]
    mlx5_cmd_do+0x22/0xc0 [mlx5_core]
    mlx5_cmd_exec+0x17/0x30 [mlx5_core]
    mlx5_core_modify_cq_moderation+0x139/0x1b0 [mlx5_core]
    ? mlx5_add_cq_to_tasklet+0x280/0x280 [mlx5_core]
    ? lockdep_set_lock_cmp_fn+0x190/0x190
    ? process_one_work+0x659/0x1220
    mlx5e_rx_dim_work+0x9d/0x100 [mlx5_core]
    process_one_work+0x730/0x1220
    ? lockdep_hardirqs_on_prepare+0x400/0x400
    ? max_active_store+0xf0/0xf0
    ? assign_work+0x168/0x240
    worker_thread+0x70f/0x12d0
    ? __kthread_parkme+0xd1/0x1d0
    ? process_one_work+0x1220/0x1220
    kthread+0x2d9/0x3b0
    ? kthread_complete_and_exit+0x20/0x20
    ret_from_fork+0x2d/0x70
    ? kthread_complete_and_exit+0x20/0x20
    ret_from_fork_asm+0x11/0x20
    </TASK>
    Modules linked in: xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay mlx5_ib ib_uverbs ib_core zram zsmalloc mlx5_core fuse
    ---[ end trace 0000000000000000 ]---

Fixes: 3178308ad4ca ("net/mlx5e: Make tx_port_ts logic resilient to out-of-order CQEs")
Signed-off-by: Rahul Rameshbabu <[email-masked]>
Reviewed-by: Tariq Toukan <[email-masked]>
Signed-off-by: Saeed Mahameed <[email-masked]>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_tx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
index 19f2c25b05a0..f0b506e562df 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
@@ -399,9 +399,9 @@ mlx5e_txwqe_complete(struct mlx5e_txqsq *sq, struct sk_buff *skb,
 		u8 metadata_index = be32_to_cpu(eseg->flow_table_metadata);
 
 		mlx5e_skb_cb_hwtstamp_init(skb);
-		mlx5e_ptpsq_track_metadata(sq->ptpsq, metadata_index);
 		mlx5e_ptp_metadata_map_put(&sq->ptpsq->metadata_map, skb,
 					   metadata_index);
+		mlx5e_ptpsq_track_metadata(sq->ptpsq, metadata_index);
 		if (!netif_tx_queue_stopped(sq->txq) &&
 		    mlx5e_ptpsq_metadata_freelist_empty(sq->ptpsq)) {
 			netif_tx_stop_queue(sq->txq);
-- 
2.41.0