From 3fba53d78015ba205d3c0d290e158889204d94f9 Mon Sep 17 00:00:00 2001
From: Fabian Keil <fk@fabiankeil.de>
Date: Wed, 21 Jan 2026 12:04:15 +0100
Subject: [PATCH] ahci: Don't try to tell the XPT about resets if the periph is
 already gone

Prevents:

    (kgdb) where
    #0  __curthread () at /usr/src/sys/amd64/include/pcpu_aux.h:57
    #1  doadump (textdump=textdump@entry=1) at /usr/src/sys/kern/kern_shutdown.c:405
    #2  0xffffffff80a20210 in kern_reboot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:523
    #3  0xffffffff80a20719 in vpanic (fmt=0xffffffff80f82397 "%s", ap=ap@entry=0xfffffe00a2c40af0) at /usr/src/sys/kern/kern_shutdown.c:967
    #4  0xffffffff80a20553 in panic (fmt=<unavailable>) at /usr/src/sys/kern/kern_shutdown.c:891
    #5  0xffffffff80ec27c0 in trap_fatal (frame=<optimized out>, eva=<optimized out>) at /usr/src/sys/amd64/amd64/trap.c:1000
    #6  0xffffffff80ec27c0 in trap_pfault (frame=0xfffffe00a2c40b70, usermode=false, signo=<optimized out>, ucode=<optimized out>)
    #7  <signal handler called>
    #8  0xffffffff80369a76 in xpt_async (async_code=1, path=0xfffff8000606ef40, async_arg=0x0) at /usr/src/sys/cam/cam_xpt.c:4321
    #9  0xffffffff804bb529 in ahci_reset (ch=ch@entry=0xfffffe0013f5e000) at /usr/src/sys/dev/ahci/ahci.c:2512
    #10 0xffffffff804b957a in ahciaction (sim=<optimized out>, ccb=0xfffff80003997000) at /usr/src/sys/dev/ahci/ahci.c:2846
    #11 0xffffffff80367d38 in xpt_action_default (start_ccb=0xfffff80003997000) at /usr/src/sys/cam/cam_xpt.c:2689
    #12 0xffffffff80374cc3 in ata_scan_bus (periph=<optimized out>, request_ccb=0xfffff80014905000) at /usr/src/sys/cam/ata/ata_xpt.c:1424
    #13 0xffffffff8036ebb1 in xpt_action (start_ccb=<optimized out>) at /usr/src/sys/cam/cam_xpt.c:2526
    #14 xpt_scanner_thread (dummy=<optimized out>) at /usr/src/sys/cam/cam_xpt.c:823
    #15 0xffffffff809d7371 in fork_exit (callout=0xffffffff8036ea50 <xpt_scanner_thread>, arg=0x0, frame=0xfffffe00a2c40f40) at /usr/src/sys/kern/kern_fork.c:1153
    #16 <signal handler called>
    (kgdb) f 9
    #9  0xffffffff804bb529 in ahci_reset (ch=ch@entry=0xfffffe0013f5e000) at /usr/src/sys/dev/ahci/ahci.c:2512
    2512            xpt_async(AC_BUS_RESET, ch->path, NULL);
    (kgdb) p *ch->path
    $8 = {periph = 0x0, bus = 0x0, target = 0x0, device = 0x0}

Obtained from: ElectroBSD
---
 sys/dev/ahci/ahci.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sys/dev/ahci/ahci.c b/sys/dev/ahci/ahci.c
index 6b5ddef2e3be..30cd6b0b44de 100644
--- a/sys/dev/ahci/ahci.c
+++ b/sys/dev/ahci/ahci.c
@@ -2508,8 +2508,11 @@ ahci_reset(struct ahci_channel *ch)
 	ch->toslots = 0;
 	ch->wrongccs = 0;
 	ch->fatalerr = 0;
-	/* Tell the XPT about the event */
-	xpt_async(AC_BUS_RESET, ch->path, NULL);
+	/* Tell the XPT about the event if we still can. */
+	if (xpt_path_periph(ch->path) != NULL)
+		xpt_async(AC_BUS_RESET, ch->path, NULL);
+	else
+		device_printf(ch->dev, "AHCI reset: periph already gone.\n");
 	/* Disable port interrupts */
 	ATA_OUTL(ch->r_mem, AHCI_P_IE, 0);
 	/* Reset and reconnect PHY, */
-- 
2.52.0