From: Mathieu Othacehe Date: Fri, 9 May 2025 12:19:35 +0000 (+0200) Subject: net: cadence: macb: Fix a possible deadlock in macb_halt_tx. X-Git-Tag: v6.15-rc7~26^2~26 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c92d6089d8ad7d4d815ebcedee3f3907b539ff1f;p=thirdparty%2Flinux.git net: cadence: macb: Fix a possible deadlock in macb_halt_tx. 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 Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250509121935.16282-1-othacehe@gnu.org Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index 1fe8ec37491b1..e1e8bd2ec155b 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -997,22 +997,15 @@ 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)