diff mbox series

[v5,net-next,6/8] hsr: Synchronize sequence number updates.

Message ID 20221129164815.128922-7-bigeasy@linutronix.de (mailing list archive)
State Accepted
Commit 5c7aa13210c3abdd34fd421f62347665ec6eb551
Delegated to: Netdev Maintainers
Headers show
Series [v5,net-next,1/8] Revert "net: hsr: use hlist_head instead of list_head for mac addresses" | expand

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netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers fail 1 blamed authors not CCed: Arvid.Brodin@xdin.com; 2 maintainers not CCed: Arvid.Brodin@xdin.com claudiajkang@gmail.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: Please use correct Fixes: style 'Fixes: <12 chars of sha1> ("<title line>")' - ie: 'Fixes: f421436a591d ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")'
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Sebastian Andrzej Siewior Nov. 29, 2022, 4:48 p.m. UTC
hsr_register_frame_out() compares new sequence_nr vs the old one
recorded in hsr_node::seq_out and if the new sequence_nr is higher then
it will be written to hsr_node::seq_out as the new value.

This operation isn't locked so it is possible that two frames with the
same sequence number arrive (via the two slave devices) and are fed to
hsr_register_frame_out() at the same time. Both will pass the check and
update the sequence counter later to the same value. As a result the
content of the same packet is fed into the stack twice.

This was noticed by running ping and observing DUP being reported from
time to time.

Instead of using the hsr_priv::seqnr_lock for the whole receive path (as
it is for sending in the master node) add an additional lock that is only
used for sequence number checks and updates.

Add a per-node lock that is used during sequence number reads and
updates.

Fixes: f421436a591d3 ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 net/hsr/hsr_framereg.c | 9 ++++++++-
 net/hsr/hsr_framereg.h | 2 ++
 2 files changed, 10 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
index f2dd846ff9038..39a6088080e93 100644
--- a/net/hsr/hsr_framereg.c
+++ b/net/hsr/hsr_framereg.c
@@ -157,6 +157,7 @@  static struct hsr_node *hsr_add_node(struct hsr_priv *hsr,
 		return NULL;
 
 	ether_addr_copy(new_node->macaddress_A, addr);
+	spin_lock_init(&new_node->seq_out_lock);
 
 	/* We are only interested in time diffs here, so use current jiffies
 	 * as initialization. (0 could trigger an spurious ring error warning).
@@ -353,6 +354,7 @@  void hsr_handle_sup_frame(struct hsr_frame_info *frame)
 	}
 
 	ether_addr_copy(node_real->macaddress_B, ethhdr->h_source);
+	spin_lock_bh(&node_real->seq_out_lock);
 	for (i = 0; i < HSR_PT_PORTS; i++) {
 		if (!node_curr->time_in_stale[i] &&
 		    time_after(node_curr->time_in[i], node_real->time_in[i])) {
@@ -363,6 +365,7 @@  void hsr_handle_sup_frame(struct hsr_frame_info *frame)
 		if (seq_nr_after(node_curr->seq_out[i], node_real->seq_out[i]))
 			node_real->seq_out[i] = node_curr->seq_out[i];
 	}
+	spin_unlock_bh(&node_real->seq_out_lock);
 	node_real->addr_B_port = port_rcv->type;
 
 	spin_lock_bh(&hsr->list_lock);
@@ -456,13 +459,17 @@  void hsr_register_frame_in(struct hsr_node *node, struct hsr_port *port,
 int hsr_register_frame_out(struct hsr_port *port, struct hsr_node *node,
 			   u16 sequence_nr)
 {
+	spin_lock_bh(&node->seq_out_lock);
 	if (seq_nr_before_or_eq(sequence_nr, node->seq_out[port->type]) &&
 	    time_is_after_jiffies(node->time_out[port->type] +
-	    msecs_to_jiffies(HSR_ENTRY_FORGET_TIME)))
+	    msecs_to_jiffies(HSR_ENTRY_FORGET_TIME))) {
+		spin_unlock_bh(&node->seq_out_lock);
 		return 1;
+	}
 
 	node->time_out[port->type] = jiffies;
 	node->seq_out[port->type] = sequence_nr;
+	spin_unlock_bh(&node->seq_out_lock);
 	return 0;
 }
 
diff --git a/net/hsr/hsr_framereg.h b/net/hsr/hsr_framereg.h
index b5f902397bf1a..b23556251d621 100644
--- a/net/hsr/hsr_framereg.h
+++ b/net/hsr/hsr_framereg.h
@@ -69,6 +69,8 @@  void prp_update_san_info(struct hsr_node *node, bool is_sup);
 
 struct hsr_node {
 	struct list_head	mac_list;
+	/* Protect R/W access to seq_out */
+	spinlock_t		seq_out_lock;
 	unsigned char		macaddress_A[ETH_ALEN];
 	unsigned char		macaddress_B[ETH_ALEN];
 	/* Local slave through which AddrB frames are received from this node */