[PATCH] net: cadence: macb: Fix a possible deadlock in macb_halt_tx.
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STALE540d
From: Mathieu Othacehe <hidden>
Date: 2025-05-07 10:12:42
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lkml
Subsystem:
atmel macb ethernet driver, networking drivers, the rest · Maintainers:
Théo Lebrun, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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. Signed-off-by: Mathieu Othacehe <redacted> --- drivers/net/ethernet/cadence/macb_main.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 1fe8ec37491b1..ffcf569c14f6a 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c@@ -997,20 +997,19 @@ static void macb_update_stats(struct macb *bp) static int macb_halt_tx(struct macb *bp) { - unsigned long halt_time, timeout; - u32 status; + unsigned int delay_us = 250; + unsigned int retries = MACB_HALT_TIMEOUT / delay_us; + 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)); + udelay(delay_us); + } while (retries-- > 0); return -ETIMEDOUT; }
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2.49.0