6.6-stable review patch. If anyone has any objections, please let me know.
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From: Mathieu Othacehe othacehe@gnu.org
[ Upstream commit c92d6089d8ad7d4d815ebcedee3f3907b539ff1f ]
There is a situation where after THALT is set high, TGO stays high as well. Because jiffies are never updated, as we are in a context with interrupts disabled, we never exit that loop and have a deadlock.
That deadlock was noticed on a sama5d4 device that stayed locked for days.
Use retries instead of jiffies so that the timeout really works and we do not have a deadlock anymore.
Fixes: e86cd53afc590 ("net/macb: better manage tx errors") Signed-off-by: Mathieu Othacehe othacehe@gnu.org Reviewed-by: Simon Horman horms@kernel.org Link: https://patch.msgid.link/20250509121935.16282-1-othacehe@gnu.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/cadence/macb_main.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-)
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index 4325d0ace1f26..6f45f4d9fba71 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -1016,22 +1016,15 @@ static void macb_update_stats(struct macb *bp)
static int macb_halt_tx(struct macb *bp) { - unsigned long halt_time, timeout; - u32 status; + u32 status;
macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(THALT));
- timeout = jiffies + usecs_to_jiffies(MACB_HALT_TIMEOUT); - do { - halt_time = jiffies; - status = macb_readl(bp, TSR); - if (!(status & MACB_BIT(TGO))) - return 0; - - udelay(250); - } while (time_before(halt_time, timeout)); - - return -ETIMEDOUT; + /* Poll TSR until TGO is cleared or timeout. */ + return read_poll_timeout_atomic(macb_readl, status, + !(status & MACB_BIT(TGO)), + 250, MACB_HALT_TIMEOUT, false, + bp, TSR); }
static void macb_tx_unmap(struct macb *bp, struct macb_tx_skb *tx_skb, int budget)