From 8f5ccba09a3fecc3d0fc80f235fb4e427aa009f8 Mon Sep 17 00:00:00 2001 From: Oscar Maes Date: Thu, 28 May 2026 16:03:20 +0200 Subject: [PATCH] pcnet32: stop holding device spin lock during napi_complete_done [ Upstream commit 73bf3cca7de6a73f53b6a52dc3b1c82ae5667a4d ] napi_complete_done may call gro_flush_normal (though not currently, as GRO is unsupported at the moment), which may result in packet TX. This will eventually result in calling pcnet32_start_xmit - resulting in a deadlock while trying to re-acquire the already locked spin lock. It is safe to split the spinlock block into two, because the hardware registers are still protected from concurrent access, and the two blocks perform unrelated operations that don't need to happen atomically. Fixes: 5b2ec6f2be51 ("pcnet32: use napi_complete_done()") Reviewed-by: Andrew Lunn Signed-off-by: Oscar Maes Reviewed-by: Alexander Lobakin Link: https://patch.msgid.link/20260528140320.5556-1-oscmaes92@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/amd/pcnet32.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/amd/pcnet32.c b/drivers/net/ethernet/amd/pcnet32.c index 70d76fdb9f56..58a59b2d70cf 100644 --- a/drivers/net/ethernet/amd/pcnet32.c +++ b/drivers/net/ethernet/amd/pcnet32.c @@ -1399,8 +1399,10 @@ static int pcnet32_poll(struct napi_struct *napi, int budget) pcnet32_restart(dev, CSR0_START); netif_wake_queue(dev); } + spin_unlock_irqrestore(&lp->lock, flags); if (work_done < budget && napi_complete_done(napi, work_done)) { + spin_lock_irqsave(&lp->lock, flags); /* clear interrupt masks */ val = lp->a->read_csr(ioaddr, CSR3); val &= 0x00ff; @@ -1408,9 +1410,9 @@ static int pcnet32_poll(struct napi_struct *napi, int budget) /* Set interrupt enable. */ lp->a->write_csr(ioaddr, CSR0, CSR0_INTEN); + spin_unlock_irqrestore(&lp->lock, flags); } - spin_unlock_irqrestore(&lp->lock, flags); return work_done; }