Date: Sun, 19 Jul 2026 18:50:51 +0000 From: Adrian Chadd <adrian@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Cc: =?utf-8?Q?J=C3=A9r=C3=A9mie?= Jourdin <jeremie@jourdin.org> Subject: git: 42f3088bd980 - main - re(4): harden re_watchdog() recovery and log controller state Message-ID: <6a5d1c8b.3fc27.7b18b3@gitrepo.freebsd.org>
index | next in thread | raw e-mail
The branch main has been updated by adrian: URL: https://cgit.FreeBSD.org/src/commit/?id=42f3088bd980a469dbbc3e6b568edb7ce0ab2bc3 commit 42f3088bd980a469dbbc3e6b568edb7ce0ab2bc3 Author: Jérémie Jourdin <jeremie@jourdin.org> AuthorDate: 2026-07-19 18:47:17 +0000 Commit: Adrian Chadd <adrian@FreeBSD.org> CommitDate: 2026-07-19 18:47:21 +0000 re(4): harden re_watchdog() recovery and log controller state Distinguish the two failure classes from the PR in a single log line (ring indices, ISR/IMR, TXCFG, interrupt mode): lost interrupt vs genuine DMA stall. Bail out instead of re-initializing when the controller reads back all-ones (fallen off the bus; reinit cannot help). Re-assert the driver's existing ASPM-disabled policy before reinit, since firmware/power transitions re-arming L0s/L1 is a documented stall trigger. Diagnostics-only on the recovered path; no fast-path change. * Field diagnostics running on an RTL8168H production fleet; the log format distinguishes lost-doorbell / DMA-stall / dead-controller without a debug build. Reviewed by: adrian Differential Revision: https://reviews.freebsd.org/D58279 PR: kern/166724 --- sys/dev/re/if_re.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 58 insertions(+), 3 deletions(-) diff --git a/sys/dev/re/if_re.c b/sys/dev/re/if_re.c index b04dc3cbaf4a..5a3e8e68d26f 100644 --- a/sys/dev/re/if_re.c +++ b/sys/dev/re/if_re.c @@ -3600,6 +3600,8 @@ re_watchdog(struct rl_softc *sc) { struct epoch_tracker et; if_t ifp; + const char *imode; + uint32_t isr, imr, txcfg; RL_LOCK_ASSERT(sc); @@ -3607,18 +3609,71 @@ re_watchdog(struct rl_softc *sc) return; ifp = sc->rl_ifp; + /* + * Snapshot the controller state before reclaim for the diagnostics + * below. Reading RL_ISR is side-effect free: the interrupt status + * is cleared by writing ones, not by reading. + */ + imode = (sc->rl_flags & RL_FLAG_MSIX) ? "MSI-X" : + (sc->rl_flags & RL_FLAG_MSI) ? "MSI" : "INTx"; + isr = CSR_READ_2(sc, RL_ISR); + imr = CSR_READ_2(sc, RL_IMR); re_txeof(sc); if (sc->rl_ldata.rl_tx_free == sc->rl_ldata.rl_tx_desc_cnt) { - if_printf(ifp, "watchdog timeout (missed Tx interrupts) " - "-- recovering\n"); + /* + * The retry reclaim drained the ring: a Tx completion interrupt + * was lost. Log the interrupt state so the lost-interrupt path + * can be diagnosed without a debug build. + */ + if_printf(ifp, "watchdog timeout (missed Tx interrupts) -- " + "recovering (ISR 0x%04x IMR 0x%04x %s)\n", + isr, imr, imode); if (!if_sendq_empty(ifp)) re_start_locked(ifp); return; } - if_printf(ifp, "watchdog timeout\n"); + txcfg = CSR_READ_4(sc, RL_TXCFG); + /* + * A genuine Tx stall. Log the Tx ring position and controller + * state in a single line -- enough to distinguish a lost doorbell, + * a DMA stall, and a controller that has fallen off the bus. + */ + if_printf(ifp, "watchdog timeout -- resetting (tx %d/%d cons %d " + "prod %d ISR 0x%04x IMR 0x%04x TXCFG 0x%08x %s)\n", + sc->rl_ldata.rl_tx_free, sc->rl_ldata.rl_tx_desc_cnt, + sc->rl_ldata.rl_tx_considx, sc->rl_ldata.rl_tx_prodidx, + isr, imr, txcfg, imode); if_inc_counter(ifp, IFCOUNTER_OERRORS, 1); + /* + * If the controller reads back all-ones it has fallen off the bus; + * re_init_locked() cannot recover it, so flag it and bail rather + * than spinning through reset after reset. + */ + if (txcfg == 0xFFFFFFFF) { + if_printf(ifp, + "controller not responding; not reinitializing\n"); + return; + } + + /* + * ASPM is a common cause of these Tx timeouts. Make sure L0s/L1 + * and CLKREQ are still disabled on the link before reinitializing; + * firmware or a power transition may have re-armed them. + */ + if (sc->rl_expcap != 0) { + uint16_t ctl; + + ctl = pci_read_config(sc->rl_dev, + sc->rl_expcap + PCIER_LINK_CTL, 2); + if ((ctl & (PCIEM_LINK_CTL_ECPM | PCIEM_LINK_CTL_ASPMC)) != 0) { + ctl &= ~(PCIEM_LINK_CTL_ECPM | PCIEM_LINK_CTL_ASPMC); + pci_write_config(sc->rl_dev, + sc->rl_expcap + PCIER_LINK_CTL, ctl, 2); + } + } + NET_EPOCH_ENTER(et); re_rxeof(sc, NULL); NET_EPOCH_EXIT(et);home | help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?6a5d1c8b.3fc27.7b18b3>