On Sat, Jan 17, 2026 at 07:53:14PM -0800, Mike Larkin wrote:
> On Sat, Jan 17, 2026 at 12:18:28PM +0100, Walter Alejandro Iglesias wrote:
> > This machine, apparently, hibernates correctly.  Then, booting after the
> > hibernation is complete, also apparently, unhibernates correctly.  But,
> > sometimes right after the image is uncompressed, sometimes after some
> > command is executed in the console, sometimes later, you always end up
> > with this same kernel panic (photos included in tarball):
> >
> >    https://en.roquesor.com/Downloads/panic.tar.gz
> >
> > As I mentioned to mlarkin@ and krw@ in private, I knew for certain that
> > this didn't happen with this machine.  I used to test how it hibernated
> > because I had it connected to a UPS when I used it (for many years) as a
> > home mail-web server.  And even though it's an old machine, I still use
> > it occasionally, which is why I took the time to do the trace back.
> >
> > After three days installing snapshots I could find out in which one the
> > panic starts happening and which modification causes it.
> >
> > This is the last snapshot working fine (the number of the beast :-):
> >
> >   https://openbsd.cs.toronto.edu/archive/2025-05-22/amd64
> >
> >   kern.version=OpenBSD 7.7-current (GENERIC.MP) #666: Wed May 21 00:12:25 
> > MDT 2025
> >     [email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
> >
> > And this is the first when the issue appears:
> >
> >   https://openbsd.cs.toronto.edu/archive/2025-05-23/amd64
> >
> >   kern.version=OpenBSD 7.7-current (GENERIC.MP) #667: Thu May 22 22:13:35 
> > MDT 2025
> >     [email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
> >
> > The modification that causes the issue is this:
> >
> >   https://marc.info/?l=openbsd-cvs&m=174779996216651&w=2
> >
> > After reverting those Mike's diffs in current, the panic disappears.
> >
> 
> I'll take a look at those diff again but I don't see how this could be the
> problem.

Without being any expert, I initially thought the same; in fact, I tried
these patches only because there were no others around that date that
seemed related.

Also, as krw@ told us privately, I deduced that something has to corrupt
either the reserved memory or the image when creating it.

> That diff just moved the allocation earlier. Maybe there's a double
> free. I'll look.

Intuitively, reviewing 'subr_hibernate.c.diff', the first that came to
my mind was to try changing back the way km_free() is redistributed in
your diff.  I'm still inexperienced with this, they might be blind
swings, but who knows, maybe I'll hit it by accident. :-)

Keep in mind that I took great care in reverting those patches
correctly, and just as the machine was started and resumed from
hibernation, I used it for hours without experiencing a kernel panic.

Finally, the first time I mentioned you this problem some months ago, I
ran checks on the RAM and the disk, apparently both are functioning
properly.


> 
> -ml
> 
> >
> > dmesg:
> > OpenBSD 7.8-current (GENERIC.MP) #206: Thu Jan 15 00:37:15 MST 2026
> >     [email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
> > real mem = 4269477888 (4071MB)
> > avail mem = 4113260544 (3922MB)
> > random: good seed from bootblocks
> > mpath0 at root
> > scsibus0 at mpath0: 256 targets
> > mainbus0 at root
> > bios0 at mainbus0: SMBIOS rev. 2.4 @ 0xeb920 (70 entries)
> > bios0: vendor Hewlett-Packard version "786E1 v01.16" date 08/17/2011
> > bios0: Hewlett-Packard HP Compaq dc7700 Convertible Minitower
> > acpi0 at bios0: ACPI 1.0
> > acpi0: sleep states S0 S3 S4 S5
> > acpi0: tables DSDT FACP APIC ASF! MCFG TCPA SLIC HPET
> > acpi0: wakeup devices PCI0(S4) COM1(S4) PEG1(S4) IGBE(S4) PCX1(S4) PCX2(S4) 
> > HUB_(S4) USB1(S3) USB2(S3) USB3(S3) USB4(S3) USB5(S3) EUS1(S3) EUS2(S3) 
> > PBTN(S4)
> > acpitimer0 at acpi0: 3579545 Hz, 24 bits
> > acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat
> > cpu0 at mainbus0: apid 0 (boot processor)
> > cpu0: Intel(R) Core(TM)2 CPU 4300 @ 1.80GHz, 1795.56 MHz, 06-0f-02, patch 
> > 0000005d
> > cpu0: cpuid 1 
> > edx=bfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
> >  ecx=e39d<SSE3,DTES64,MWAIT,DS-CPL,EST,TM2,SSSE3,CX16,xTPR,PDCM>
> > cpu0: cpuid 6 eax=1<SENSOR> ecx=1<EFFFREQ>
> > cpu0: cpuid a vers=2, gp=2, gpwidth=40, ff=0, ffwidth=0
> > cpu0: cpuid 80000001 edx=20100800<NXE,LONG> ecx=1<LAHF>
> > cpu0: MELTDOWN
> > cpu0: 32KB 64b/line 8-way D-cache, 32KB 64b/line 8-way I-cache, 2MB 
> > 64b/line 8-way L2 cache
> > cpu0: smt 0, core 0, package 0
> > mtrr: Pentium Pro MTRR support, 8 var ranges, 88 fixed ranges
> > cpu0: apic clock running at 199MHz
> > cpu0: mwait min=64, max=64, C-substates=0.2, IBE
> > cpu1 at mainbus0: apid 1 (application processor)
> > cpu1: Intel(R) Core(TM)2 CPU 4300 @ 1.80GHz, 1795.66 MHz, 06-0f-02, patch 
> > 0000005d
> > cpu1: smt 0, core 1, package 0
> > ioapic0 at mainbus0: apid 1 pa 0xfec00000, version 20, 24 pins, remapped
> > acpimcfg0 at acpi0
> > acpimcfg0: addr 0xf4000000, bus 0-63
> > acpihpet0 at acpi0: 14318179 Hz
> > acpiprt0 at acpi0: bus 0 (PCI0)
> > acpiprt1 at acpi0: bus -1 (PEG1)
> > acpiprt2 at acpi0: bus 32 (PCX1)
> > acpiprt3 at acpi0: bus -1 (PCX2)
> > acpiprt4 at acpi0: bus 7 (HUB_)
> > acpipci0 at acpi0 PCI0: 0x00000000 0x00000011 0x00000001
> > acpicmos0 at acpi0
> > "PNP0F13" at acpi0 not configured
> > "PNP0303" at acpi0 not configured
> > com0 at acpi0 COM1 addr 0x3f8/0x8 irq 4: ns16550a, 16 byte fifo
> > "PNP0003" at acpi0 not configured
> > acpibtn0 at acpi0: PBTN(wakeup)
> > "PNP0C14" at acpi0 not configured
> > acpicpu0 at acpi0: C1(@1 halt!), PSS
> > acpicpu1 at acpi0: C1(@1 halt!), PSS
> > cpu0: Enhanced SpeedStep 1795 MHz: speeds: 1800, 1200 MHz
> > pci0 at mainbus0 bus 0
> > pchb0 at pci0 dev 0 function 0 "Intel 82Q965 Host" rev 0x02
> > inteldrm0 at pci0 dev 2 function 0 "Intel 82Q965 Video" rev 0x02
> > drm0 at inteldrm0
> > intagp0 at inteldrm0
> > agp0 at intagp0: aperture at 0xe0000000, size 0x10000000
> > inteldrm0: apic 1 int 16, I965G, gen 4
> > em0 at pci0 dev 25 function 0 "Intel ICH8 IGP AMT" rev 0x02: apic 1 int 19, 
> > address 00:0f:fe:77:4f:df
> > uhci0 at pci0 dev 26 function 0 "Intel 82801H USB" rev 0x02: apic 1 int 20
> > uhci1 at pci0 dev 26 function 1 "Intel 82801H USB" rev 0x02: apic 1 int 21
> > ehci0 at pci0 dev 26 function 7 "Intel 82801H USB" rev 0x02: apic 1 int 22
> > usb0 at ehci0: USB revision 2.0
> > uhub0 at usb0 configuration 1 interface 0 "Intel EHCI root hub" rev 
> > 2.00/1.00 addr 1
> > azalia0 at pci0 dev 27 function 0 "Intel 82801H HD Audio" rev 0x02: apic 1 
> > int 21
> > azalia0: codecs: Realtek ALC262
> > audio0 at azalia0
> > ppb0 at pci0 dev 28 function 0 "Intel 82801H PCIE" rev 0x02
> > pci1 at ppb0 bus 32
> > uhci2 at pci0 dev 29 function 0 "Intel 82801H USB" rev 0x02: apic 1 int 20
> > uhci3 at pci0 dev 29 function 1 "Intel 82801H USB" rev 0x02: apic 1 int 21
> > ehci1 at pci0 dev 29 function 7 "Intel 82801H USB" rev 0x02: apic 1 int 20
> > usb1 at ehci1: USB revision 2.0
> > uhub1 at usb1 configuration 1 interface 0 "Intel EHCI root hub" rev 
> > 2.00/1.00 addr 1
> > ppb1 at pci0 dev 30 function 0 "Intel 82801BA Hub-to-PCI" rev 0xf2
> > pci2 at ppb1 bus 7
> > pcib0 at pci0 dev 31 function 0 "Intel 82801HO LPC" rev 0x02
> > pciide0 at pci0 dev 31 function 2 "Intel 82801H SATA" rev 0x02: DMA, 
> > channel 0 configured to native-PCI, channel 1 configured to native-PCI
> > pciide0: using apic 1 int 18 for native-PCI interrupt
> > wd0 at pciide0 channel 0 drive 0: <KINGSTON SA400S37240G>
> > wd0: 1-sector PIO, LBA48, 228936MB, 468862128 sectors
> > wd0(pciide0:0:0): using PIO mode 4, Ultra-DMA mode 6
> > usb2 at uhci0: USB revision 1.0
> > uhub2 at usb2 configuration 1 interface 0 "Intel UHCI root hub" rev 
> > 1.00/1.00 addr 1
> > usb3 at uhci1: USB revision 1.0
> > uhub3 at usb3 configuration 1 interface 0 "Intel UHCI root hub" rev 
> > 1.00/1.00 addr 1
> > usb4 at uhci2: USB revision 1.0
> > uhub4 at usb4 configuration 1 interface 0 "Intel UHCI root hub" rev 
> > 1.00/1.00 addr 1
> > usb5 at uhci3: USB revision 1.0
> > uhub5 at usb5 configuration 1 interface 0 "Intel UHCI root hub" rev 
> > 1.00/1.00 addr 1
> > isa0 at pcib0
> > isadma0 at isa0
> > fdc0 at isa0 port 0x3f0/6 irq 6 drq 2
> > pckbc0 at isa0 port 0x60/5 irq 1 irq 12
> > pckbd0 at pckbc0 (kbd slot)
> > wskbd0 at pckbd0: console keyboard
> > pms0 at pckbc0 (aux slot)
> > wsmouse0 at pms0 mux 0
> > pcppi0 at isa0 port 0x61
> > spkr0 at pcppi0
> > lpt0 at isa0 port 0x378/4 irq 7
> > vscsi0 at root
> > scsibus1 at vscsi0: 256 targets
> > softraid0 at root
> > scsibus2 at softraid0: 256 targets
> > root on wd0a (14e7147b497b7d69.a) swap on wd0b dump on wd0b
> > inteldrm0: 1680x1050, 32bpp
> > wsdisplay0 at inteldrm0 mux 1: console (std, vt100 emulation), using wskbd0
> > wsdisplay0: screen 1-5 added (std, vt100 emulation)
> >
> > usbdevs:
> > Controller /dev/usb0:
> > addr 01: 8086:0000 Intel, EHCI root hub
> >      high speed, self powered, config 1, rev 1.00
> >      driver: uhub0
> > Controller /dev/usb1:
> > addr 01: 8086:0000 Intel, EHCI root hub
> >      high speed, self powered, config 1, rev 1.00
> >      driver: uhub1
> > Controller /dev/usb2:
> > addr 01: 8086:0000 Intel, UHCI root hub
> >      full speed, self powered, config 1, rev 1.00
> >      driver: uhub2
> > Controller /dev/usb3:
> > addr 01: 8086:0000 Intel, UHCI root hub
> >      full speed, self powered, config 1, rev 1.00
> >      driver: uhub3
> > Controller /dev/usb4:
> > addr 01: 8086:0000 Intel, UHCI root hub
> >      full speed, self powered, config 1, rev 1.00
> >      driver: uhub4
> > Controller /dev/usb5:
> > addr 01: 8086:0000 Intel, UHCI root hub
> >      full speed, self powered, config 1, rev 1.00
> >      driver: uhub5
> >
> > --
> > Walter
> >

-- 
Walter

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