Message-ID: <20240918205719.64214-1-greearb@candelatech.com>
Date: Wed, 18 Sep 2024 13:57:19 -0700
From: greearb@...delatech.com
To: netdev@...r.kernel.org
Cc: Ben Greear <greearb@...delatech.com>
Subject: [PATCH] af_packet:  Fix softirq mismatch in tpacket_rcv

From: Ben Greear <greearb@...delatech.com>

tpacket_rcv can be called from softirq context on input
path from NIC to stack.  And also called on transmit path
when sniffing is enabled.  So, use _bh locks to allow this
to function properly.

Thanks to Johannes Berg for providing some explanation of the cryptic
lockdep output.

================================
WARNING: inconsistent lock state
6.11.0 #1 Tainted: G        W
--------------------------------
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
btserver/134819 [HC0[0]:SC0[0]:HE1:SE1] takes:
ffff8882da30c118 (rlock-AF_PACKET){+.?.}-{2:2}, at: tpacket_rcv+0x863/0x3b30
{IN-SOFTIRQ-W} state was registered at:
  lock_acquire+0x19a/0x4f0
  _raw_spin_lock+0x27/0x40
  packet_rcv+0xa33/0x1320
  __netif_receive_skb_core.constprop.0+0xcb0/0x3a90
  __netif_receive_skb_list_core+0x2c9/0x890
  netif_receive_skb_list_internal+0x610/0xcc0
  napi_complete_done+0x1c0/0x7c0
  igb_poll+0x1dbb/0x57e0 [igb]
  __napi_poll.constprop.0+0x99/0x430
  net_rx_action+0x8e7/0xe10
  handle_softirqs+0x1b7/0x800
  __irq_exit_rcu+0x91/0xc0
  irq_exit_rcu+0x5/0x10
  common_interrupt+0x7f/0xa0
  asm_common_interrupt+0x22/0x40
  cpuidle_enter_state+0x289/0x320
  cpuidle_enter+0x45/0xa0
  do_idle+0x2fe/0x3e0
  cpu_startup_entry+0x4b/0x60
  start_secondary+0x201/0x280
  common_startup_64+0x13e/0x148
irq event stamp: 467094363
hardirqs last  enabled at (467094363): [<ffffffff83dc794b>] _raw_spin_unlock_irqrestore+0x2b/0x50
hardirqs last disabled at (467094362): [<ffffffff83dc7753>] _raw_spin_lock_irqsave+0x53/0x60
softirqs last  enabled at (467094360): [<ffffffff83481213>] skb_attempt_defer_free+0x303/0x4e0
softirqs last disabled at (467094358): [<ffffffff83481188>] skb_attempt_defer_free+0x278/0x4e0

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(rlock-AF_PACKET);
  <Interrupt>
    lock(rlock-AF_PACKET);

 *** DEADLOCK ***

3 locks held by btserver/134819:
 #0: ffff888136a3bf98 (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_recvmsg+0xc7/0x4e0
 #1: ffffffff84e4bc20 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x59/0x1e20
 #2: ffffffff84e4bc20 (rcu_read_lock){....}-{1:2}, at: dev_queue_xmit_nit+0x2a/0xa40

stack backtrace:
CPU: 2 UID: 0 PID: 134819 Comm: btserver Tainted: G        W          6.11.0 #1
Tainted: [W]=WARN
Hardware name: Default string Default string/SKYBAY, BIOS 5.12 08/04/2020
Call Trace:
 <TASK>
 dump_stack_lvl+0x73/0xa0
 mark_lock+0x102e/0x16b0
 ? print_usage_bug.part.0+0x600/0x600
 ? print_usage_bug.part.0+0x600/0x600
 ? print_usage_bug.part.0+0x600/0x600
 ? lock_acquire+0x19a/0x4f0
 ? find_held_lock+0x2d/0x110
 __lock_acquire+0x9ae/0x6170
 ? lockdep_hardirqs_on_prepare+0x3e0/0x3e0
 ? lockdep_hardirqs_on_prepare+0x3e0/0x3e0
 lock_acquire+0x19a/0x4f0
 ? tpacket_rcv+0x863/0x3b30
 ? run_filter+0x131/0x300
 ? lock_sync+0x170/0x170
 ? do_syscall_64+0x69/0x160
 ? entry_SYSCALL_64_after_hwframe+0x4b/0x53
 ? lock_is_held_type+0xa5/0x110
 _raw_spin_lock+0x27/0x40
 ? tpacket_rcv+0x863/0x3b30
 tpacket_rcv+0x863/0x3b30
 ? packet_recvmsg+0x1340/0x1340
 ? __asan_memcpy+0x38/0x60
 ? __skb_clone+0x547/0x730
 ? packet_recvmsg+0x1340/0x1340
 dev_queue_xmit_nit+0x709/0xa40
 ? lockdep_hardirqs_on_prepare+0x3e0/0x3e0
 vrf_finish_direct+0x26e/0x340 [vrf]
 ? vrf_ip_local_out+0x570/0x570 [vrf]
 vrf_l3_out+0x5f4/0xe80 [vrf]
 __ip_local_out+0x51e/0x7a0
 ? __ip_append_data+0x3d00/0x3d00
 ? __lock_acquire+0x1b57/0x6170
 ? ipv4_dst_check+0xd6/0x150
 ? lock_is_held_type+0xa5/0x110
 __ip_queue_xmit+0x7ff/0x1e20
 __tcp_transmit_skb+0x1699/0x3850
 ? __tcp_select_window+0xfb0/0xfb0
 ? __build_skb_around+0x22f/0x330
 ? __alloc_skb+0x13d/0x2c0
 ? __napi_build_skb+0x40/0x40
 ? __tcp_send_ack.part.0+0x5f/0x690
 ? skb_attempt_defer_free+0x303/0x4e0
 tcp_recvmsg_locked+0xdd1/0x23e0
 ? tcp_recvmsg+0xc7/0x4e0
 ? tcp_update_recv_tstamps+0x1c0/0x1c0
 tcp_recvmsg+0xe5/0x4e0
 ? tcp_recv_timestamp+0x6c0/0x6c0
 inet_recvmsg+0xf0/0x4b0
 ? inet_splice_eof+0xa0/0xa0
 ? inet_splice_eof+0xa0/0xa0
 sock_recvmsg+0xc8/0x150
 ? poll_schedule_timeout.constprop.0+0xe0/0xe0
 sock_read_iter+0x258/0x380
 ? poll_schedule_timeout.constprop.0+0xe0/0xe0
 ? sock_recvmsg+0x150/0x150
 ? rw_verify_area+0x64/0x590
 vfs_read+0x8d5/0xc20
 ? poll_schedule_timeout.constprop.0+0xe0/0xe0
 ? kernel_read+0x50/0x50
 ? __asan_memset+0x1f/0x40
 ? ktime_get_ts64+0x85/0x210
 ? __fget_light+0x4d/0x1d0
 ksys_read+0x166/0x1c0
 ? __ia32_sys_pwrite64+0x1d0/0x1d0
 ? __ia32_sys_poll+0x3e0/0x3e0
 do_syscall_64+0x69/0x160
 entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7f6909b01b92

Signed-off-by: Ben Greear <greearb@...delatech.com>
---
 net/packet/af_packet.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 4692a9ef110b..17f9e2efdf25 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -760,8 +760,8 @@ static void prb_retire_rx_blk_timer_expired(struct timer_list *t)
 	 */
 	if (BLOCK_NUM_PKTS(pbd)) {
 		/* Waiting for skb_copy_bits to finish... */
-		write_lock(&pkc->blk_fill_in_prog_lock);
-		write_unlock(&pkc->blk_fill_in_prog_lock);
+		write_lock_bh(&pkc->blk_fill_in_prog_lock);
+		write_unlock_bh(&pkc->blk_fill_in_prog_lock);
 	}
 
 	if (pkc->last_kactive_blk_num == pkc->kactive_blk_num) {
@@ -1021,8 +1021,8 @@ static void prb_retire_current_block(struct tpacket_kbdq_core *pkc,
 		 */
 		if (!(status & TP_STATUS_BLK_TMO)) {
 			/* Waiting for skb_copy_bits to finish... */
-			write_lock(&pkc->blk_fill_in_prog_lock);
-			write_unlock(&pkc->blk_fill_in_prog_lock);
+			write_lock_bh(&pkc->blk_fill_in_prog_lock);
+			write_unlock_bh(&pkc->blk_fill_in_prog_lock);
 		}
 		prb_close_block(pkc, pbd, po, status);
 		return;
@@ -1044,7 +1044,7 @@ static void prb_clear_blk_fill_status(struct packet_ring_buffer *rb)
 {
 	struct tpacket_kbdq_core *pkc  = GET_PBDQC_FROM_RB(rb);
 
-	read_unlock(&pkc->blk_fill_in_prog_lock);
+	read_unlock_bh(&pkc->blk_fill_in_prog_lock);
 }
 
 static void prb_fill_rxhash(struct tpacket_kbdq_core *pkc,
@@ -1105,7 +1105,7 @@ static void prb_fill_curr_block(char *curr,
 	pkc->nxt_offset += TOTAL_PKT_LEN_INCL_ALIGN(len);
 	BLOCK_LEN(pbd) += TOTAL_PKT_LEN_INCL_ALIGN(len);
 	BLOCK_NUM_PKTS(pbd) += 1;
-	read_lock(&pkc->blk_fill_in_prog_lock);
+	read_lock_bh(&pkc->blk_fill_in_prog_lock);
 	prb_run_all_ft_ops(pkc, ppd);
 }
 
@@ -2413,7 +2413,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 			vnet_hdr_sz = 0;
 		}
 	}
-	spin_lock(&sk->sk_receive_queue.lock);
+	spin_lock_bh(&sk->sk_receive_queue.lock);
 	h.raw = packet_current_rx_frame(po, skb,
 					TP_STATUS_KERNEL, (macoff+snaplen));
 	if (!h.raw)
@@ -2453,7 +2453,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 		skb_clear_delivery_time(copy_skb);
 		__skb_queue_tail(&sk->sk_receive_queue, copy_skb);
 	}
-	spin_unlock(&sk->sk_receive_queue.lock);
+	spin_unlock_bh(&sk->sk_receive_queue.lock);
 
 	skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
 
@@ -2546,10 +2546,10 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 #endif
 
 	if (po->tp_version <= TPACKET_V2) {
-		spin_lock(&sk->sk_receive_queue.lock);
+		spin_lock_bh(&sk->sk_receive_queue.lock);
 		__packet_set_status(po, h.raw, status);
 		__clear_bit(slot_id, po->rx_ring.rx_owner_map);
-		spin_unlock(&sk->sk_receive_queue.lock);
+		spin_unlock_bh(&sk->sk_receive_queue.lock);
 		sk->sk_data_ready(sk);
 	} else if (po->tp_version == TPACKET_V3) {
 		prb_clear_blk_fill_status(&po->rx_ring);
@@ -2565,7 +2565,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 	return 0;
 
 drop_n_account:
-	spin_unlock(&sk->sk_receive_queue.lock);
+	spin_unlock_bh(&sk->sk_receive_queue.lock);
 	atomic_inc(&po->tp_drops);
 	drop_reason = SKB_DROP_REASON_PACKET_SOCK_ERROR;
 
-- 
2.42.0

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