6.6-stable review patch. If anyone has any objections, please let me know.
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From: Gerhard Engleder gerhard@engleder-embedded.com
[ Upstream commit b3ca9eef6646576ad506a96d941d87a69f66732a ]
This driver is susceptible to a form of the bug explained in commit c26a2c2ddc01 ("gianfar: Fix TX timestamping with a stacked DSA driver") and in Documentation/networking/timestamping.rst section "Other caveats for MAC drivers", specifically it timestamps any skb which has SKBTX_HW_TSTAMP, and does not consider if timestamping has been enabled in adapter->hwtstamp_config.tx_type.
Evaluate the proper TX timestamping condition only once on the TX path (in tsnep_xmit_frame_ring()) and store the result in an additional TX entry flag. Evaluate the new TX entry flag in the TX confirmation path (in tsnep_tx_poll()).
This way SKBTX_IN_PROGRESS is set by the driver as required, but never evaluated. SKBTX_IN_PROGRESS shall not be evaluated as it can be set by a stacked DSA driver and evaluating it would lead to unwanted timestamps.
Fixes: 403f69bbdbad ("tsnep: Add TSN endpoint Ethernet MAC driver") Suggested-by: Vladimir Oltean vladimir.oltean@nxp.com Signed-off-by: Gerhard Engleder gerhard@engleder-embedded.com Reviewed-by: Vladimir Oltean vladimir.oltean@nxp.com Link: https://patch.msgid.link/20250514195657.25874-1-gerhard@engleder-embedded.co... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/engleder/tsnep_main.c | 30 ++++++++++++++-------- 1 file changed, 19 insertions(+), 11 deletions(-)
diff --git a/drivers/net/ethernet/engleder/tsnep_main.c b/drivers/net/ethernet/engleder/tsnep_main.c index d8711e1511e47..215ae6745932a 100644 --- a/drivers/net/ethernet/engleder/tsnep_main.c +++ b/drivers/net/ethernet/engleder/tsnep_main.c @@ -67,6 +67,8 @@ #define TSNEP_TX_TYPE_XDP_NDO_MAP_PAGE (TSNEP_TX_TYPE_XDP_NDO | TSNEP_TX_TYPE_MAP_PAGE) #define TSNEP_TX_TYPE_XDP (TSNEP_TX_TYPE_XDP_TX | TSNEP_TX_TYPE_XDP_NDO) #define TSNEP_TX_TYPE_XSK BIT(12) +#define TSNEP_TX_TYPE_TSTAMP BIT(13) +#define TSNEP_TX_TYPE_SKB_TSTAMP (TSNEP_TX_TYPE_SKB | TSNEP_TX_TYPE_TSTAMP)
#define TSNEP_XDP_TX BIT(0) #define TSNEP_XDP_REDIRECT BIT(1) @@ -385,8 +387,7 @@ static void tsnep_tx_activate(struct tsnep_tx *tx, int index, int length, if (entry->skb) { entry->properties = length & TSNEP_DESC_LENGTH_MASK; entry->properties |= TSNEP_DESC_INTERRUPT_FLAG; - if ((entry->type & TSNEP_TX_TYPE_SKB) && - (skb_shinfo(entry->skb)->tx_flags & SKBTX_IN_PROGRESS)) + if ((entry->type & TSNEP_TX_TYPE_SKB_TSTAMP) == TSNEP_TX_TYPE_SKB_TSTAMP) entry->properties |= TSNEP_DESC_EXTENDED_WRITEBACK_FLAG;
/* toggle user flag to prevent false acknowledge @@ -478,7 +479,8 @@ static int tsnep_tx_map_frag(skb_frag_t *frag, struct tsnep_tx_entry *entry, return mapped; }
-static int tsnep_tx_map(struct sk_buff *skb, struct tsnep_tx *tx, int count) +static int tsnep_tx_map(struct sk_buff *skb, struct tsnep_tx *tx, int count, + bool do_tstamp) { struct device *dmadev = tx->adapter->dmadev; struct tsnep_tx_entry *entry; @@ -504,6 +506,9 @@ static int tsnep_tx_map(struct sk_buff *skb, struct tsnep_tx *tx, int count) entry->type = TSNEP_TX_TYPE_SKB_INLINE; mapped = 0; } + + if (do_tstamp) + entry->type |= TSNEP_TX_TYPE_TSTAMP; } else { skb_frag_t *frag = &skb_shinfo(skb)->frags[i - 1];
@@ -557,11 +562,12 @@ static int tsnep_tx_unmap(struct tsnep_tx *tx, int index, int count) static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb, struct tsnep_tx *tx) { - int count = 1; struct tsnep_tx_entry *entry; + bool do_tstamp = false; + int count = 1; int length; - int i; int retval; + int i;
if (skb_shinfo(skb)->nr_frags > 0) count += skb_shinfo(skb)->nr_frags; @@ -578,7 +584,13 @@ static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb, entry = &tx->entry[tx->write]; entry->skb = skb;
- retval = tsnep_tx_map(skb, tx, count); + if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) && + tx->adapter->hwtstamp_config.tx_type == HWTSTAMP_TX_ON) { + skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS; + do_tstamp = true; + } + + retval = tsnep_tx_map(skb, tx, count, do_tstamp); if (retval < 0) { tsnep_tx_unmap(tx, tx->write, count); dev_kfree_skb_any(entry->skb); @@ -590,9 +602,6 @@ static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb, } length = retval;
- if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) - skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS; - for (i = 0; i < count; i++) tsnep_tx_activate(tx, (tx->write + i) & TSNEP_RING_MASK, length, i == count - 1); @@ -843,8 +852,7 @@ static bool tsnep_tx_poll(struct tsnep_tx *tx, int napi_budget)
length = tsnep_tx_unmap(tx, tx->read, count);
- if ((entry->type & TSNEP_TX_TYPE_SKB) && - (skb_shinfo(entry->skb)->tx_flags & SKBTX_IN_PROGRESS) && + if (((entry->type & TSNEP_TX_TYPE_SKB_TSTAMP) == TSNEP_TX_TYPE_SKB_TSTAMP) && (__le32_to_cpu(entry->desc_wb->properties) & TSNEP_DESC_EXTENDED_WRITEBACK_FLAG)) { struct skb_shared_hwtstamps hwtstamps;