I tried to boot a kcov-enabled config which we run on syzkaller VMs on real HW today. It hung, so I minimized the hanging kernel config to just this:
include "arch/amd64/conf/GENERIC.MP" pseudo-device kcov 1 My machine is an unexciting Lenovo ThinkPad X1 Carbon 7th Gen (20QE). I marked the spot where it *would* hang in the dmesg below: OpenBSD 7.2-beta (GENERIC.MP) #711: Fri Aug 26 23:07:18 MDT 2022 dera...@amd64.openbsd.org:/usr/src/sys/arch/amd64/compile/GENERIC.MP real mem = 16793116672 (16015MB) avail mem = 16266772480 (15513MB) random: good seed from bootblocks mpath0 at root scsibus0 at mpath0: 256 targets mainbus0 at root bios0 at mainbus0: SMBIOS rev. 3.1 @ 0x6de49000 (65 entries) bios0: vendor LENOVO version "N2HET70P (1.53 )" date 06/28/2022 bios0: LENOVO 20QES6TL00 acpi0 at bios0: ACPI 6.1 acpi0: sleep states S0 S3 S4 S5 acpi0: tables DSDT FACP SSDT SSDT SSDT SSDT SSDT TPM2 UEFI SSDT HPET APIC MCFG ECDT SSDT SSDT SSDT BOOT SLIC SSDT LPIT WSMT SSDT DBGP DBG2 MSDM BATB NHLT ASF! FPDT UEFI acpi0: wakeup devices GLAN(S4) XHC_(S3) XDCI(S4) HDAS(S4) RP01(S4) PXSX(S4) RP02(S4) PXSX(S4) PXSX(S4) RP04(S4) PXSX(S4) RP05(S4) PXSX(S4) RP06(S4) PXSX(S4) RP07(S4) [...] acpitimer0 at acpi0: 3579545 Hz, 24 bits acpihpet0 at acpi0: 23999999 Hz acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat cpu0 at mainbus0: apid 0 (boot processor) cpu0: Intel(R) Core(TM) i7-8665U CPU @ 1.90GHz, 1795.82 MHz, 06-8e-0c cpu0: 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,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,TSC_ADJUST,SGX,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,SRBDS_CTRL,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES cpu0: 32KB 64b/line 8-way D-cache, 32KB 64b/line 8-way I-cache, 256KB 64b/line 4-way L2 cache, 8MB 64b/line 16-way L3 cache cpu0: smt 0, core 0, package 0 mtrr: Pentium Pro MTRR support, 10 var ranges, 88 fixed ranges cpu0: apic clock running at 24MHz cpu0: mwait min=64, max=64, C-substates=0.2.1.2.4.1.1.1, IBE cpu1 at mainbus0: apid 2 (application processor) cpu1: Intel(R) Core(TM) i7-8665U CPU @ 1.90GHz, 1795.82 MHz, 06-8e-0c cpu1: 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,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,TSC_ADJUST,SGX,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,SRBDS_CTRL,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES cpu1: 32KB 64b/line 8-way D-cache, 32KB 64b/line 8-way I-cache, 256KB 64b/line 4-way L2 cache, 8MB 64b/line 16-way L3 cache cpu1: smt 0, core 1, package 0 * hang * cpu2 at mainbus0: apid 4 (application processor) cpu2: Intel(R) Core(TM) i7-8665U CPU @ 1.90GHz, 1795.82 MHz, 06-8e-0c cpu2: 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,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,TSC_ADJUST,SGX,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,SRBDS_CTRL,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES cpu2: 32KB 64b/line 8-way D-cache, 32KB 64b/line 8-way I-cache, 256KB 64b/line 4-way L2 cache, 8MB 64b/line 16-way L3 cache cpu2: smt 0, core 2, package 0 cpu3 at mainbus0: apid 6 (application processor) cpu3: Intel(R) Core(TM) i7-8665U CPU @ 1.90GHz, 1795.82 MHz, 06-8e-0c cpu3: 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,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,TSC_ADJUST,SGX,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,SRBDS_CTRL,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES cpu3: 32KB 64b/line 8-way D-cache, 32KB 64b/line 8-way I-cache, 256KB 64b/line 4-way L2 cache, 8MB 64b/line 16-way L3 cache cpu3: smt 0, core 3, package 0 cpu4 at mainbus0: apid 1 (application processor) cpu4: Intel(R) Core(TM) i7-8665U CPU @ 1.90GHz, 1795.82 MHz, 06-8e-0c cpu4: 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,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,TSC_ADJUST,SGX,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,SRBDS_CTRL,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES cpu4: 32KB 64b/line 8-way D-cache, 32KB 64b/line 8-way I-cache, 256KB 64b/line 4-way L2 cache, 8MB 64b/line 16-way L3 cache cpu4: smt 1, core 0, package 0 cpu5 at mainbus0: apid 3 (application processor) cpu5: Intel(R) Core(TM) i7-8665U CPU @ 1.90GHz, 1795.82 MHz, 06-8e-0c cpu5: 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,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,TSC_ADJUST,SGX,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,SRBDS_CTRL,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES cpu5: 32KB 64b/line 8-way D-cache, 32KB 64b/line 8-way I-cache, 256KB 64b/line 4-way L2 cache, 8MB 64b/line 16-way L3 cache cpu5: smt 1, core 1, package 0 cpu6 at mainbus0: apid 5 (application processor) cpu6: Intel(R) Core(TM) i7-8665U CPU @ 1.90GHz, 1795.82 MHz, 06-8e-0c cpu6: 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,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,TSC_ADJUST,SGX,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,SRBDS_CTRL,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES cpu6: 32KB 64b/line 8-way D-cache, 32KB 64b/line 8-way I-cache, 256KB 64b/line 4-way L2 cache, 8MB 64b/line 16-way L3 cache cpu6: smt 1, core 2, package 0 cpu7 at mainbus0: apid 7 (application processor) cpu7: Intel(R) Core(TM) i7-8665U CPU @ 1.90GHz, 1795.82 MHz, 06-8e-0c cpu7: 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,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,TSC_ADJUST,SGX,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,SRBDS_CTRL,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES cpu7: 32KB 64b/line 8-way D-cache, 32KB 64b/line 8-way I-cache, 256KB 64b/line 4-way L2 cache, 8MB 64b/line 16-way L3 cache cpu7: smt 1, core 3, package 0 ioapic0 at mainbus0: apid 2 pa 0xfec00000, version 20, 120 pins acpimcfg0 at acpi0 acpimcfg0: addr 0xf0000000, bus 0-127 acpiec0 at acpi0 acpiprt0 at acpi0: bus 0 (PCI0) acpiprt1 at acpi0: bus -1 (RP01) acpiprt2 at acpi0: bus -1 (RP02) acpiprt3 at acpi0: bus -1 (RP03) acpiprt4 at acpi0: bus -1 (RP04) acpiprt5 at acpi0: bus -1 (RP05) acpiprt6 at acpi0: bus -1 (RP06) acpiprt7 at acpi0: bus -1 (RP07) acpiprt8 at acpi0: bus -1 (RP08) acpiprt9 at acpi0: bus 3 (RP09) acpiprt10 at acpi0: bus -1 (RP10) acpiprt11 at acpi0: bus -1 (RP11) acpiprt12 at acpi0: bus -1 (RP12) acpiprt13 at acpi0: bus 5 (RP13) acpiprt14 at acpi0: bus -1 (RP14) acpiprt15 at acpi0: bus -1 (RP15) acpiprt16 at acpi0: bus -1 (RP16) acpiprt17 at acpi0: bus -1 (RP17) acpiprt18 at acpi0: bus -1 (RP18) acpiprt19 at acpi0: bus -1 (RP19) acpiprt20 at acpi0: bus -1 (RP20) acpiprt21 at acpi0: bus -1 (RP21) acpiprt22 at acpi0: bus -1 (RP22) acpiprt23 at acpi0: bus -1 (RP23) acpiprt24 at acpi0: bus -1 (RP24) acpipci0 at acpi0 PCI0: 0x00000000 0x00000011 0x00000001 acpithinkpad0 at acpi0: version 2.0 acpiac0 at acpi0: AC unit online acpibat0 at acpi0: BAT0 model "02DL004" serial 43 type LiP oem "LGC" "PNP0C60" at acpi0 not configured "LEN0111" at acpi0 not configured "LEN0100" at acpi0 not configured "INT3403" at acpi0 not configured pchgpio0 at acpi0 GPI0 addr 0xfd6e0000/0x10000 0xfd6d0000/0x10000 0xfd6a0000/0x10000 irq 14, 320 pins "SYNA8004" at acpi0 not configured "ACPI000E" at acpi0 not configured "PNP0C14" at acpi0 not configured "INT0E0C" at acpi0 not configured acpibtn0 at acpi0: SLPB "PNP0C14" at acpi0 not configured "PNP0C14" at acpi0 not configured "INT33A1" at acpi0 not configured acpibtn1 at acpi0: LID_ "PNP0C14" at acpi0 not configured "PNP0C14" at acpi0 not configured "PNP0C14" at acpi0 not configured "PNP0C14" at acpi0 not configured "INT3400" at acpi0 not configured tpm0 at acpi0 TPM_ 2.0 (TIS) addr 0xfed40000/0x5000, device 0x0000104a rev 0x4e "USBC000" at acpi0 not configured acpipwrres0 at acpi0: PUBS, resource for XHC_ acpipwrres1 at acpi0: BTPR, resource for HS10 acpipwrres2 at acpi0: USBC, resource for XDCI acpipwrres3 at acpi0: PXP_, resource for RP01, PXSX acpipwrres4 at acpi0: PXP_, resource for RP13 acpipwrres5 at acpi0: V0PR acpipwrres6 at acpi0: V1PR acpipwrres7 at acpi0: V2PR acpipwrres8 at acpi0: WRST acpicpu0 at acpi0: C3(200@1034 mwait.1@0x60), C2(200@151 mwait.1@0x33), C1(1000@1 mwait.1), PSS acpicpu1 at acpi0: C3(200@1034 mwait.1@0x60), C2(200@151 mwait.1@0x33), C1(1000@1 mwait.1), PSS acpicpu2 at acpi0: C3(200@1034 mwait.1@0x60), C2(200@151 mwait.1@0x33), C1(1000@1 mwait.1), PSS acpicpu3 at acpi0: C3(200@1034 mwait.1@0x60), C2(200@151 mwait.1@0x33), C1(1000@1 mwait.1), PSS acpicpu4 at acpi0: C3(200@1034 mwait.1@0x60), C2(200@151 mwait.1@0x33), C1(1000@1 mwait.1), PSS acpicpu5 at acpi0: C3(200@1034 mwait.1@0x60), C2(200@151 mwait.1@0x33), C1(1000@1 mwait.1), PSS acpicpu6 at acpi0: C3(200@1034 mwait.1@0x60), C2(200@151 mwait.1@0x33), C1(1000@1 mwait.1), PSS acpicpu7 at acpi0: C3(200@1034 mwait.1@0x60), C2(200@151 mwait.1@0x33), C1(1000@1 mwait.1), PSS acpitz0 at acpi0: critical temperature is 128 degC acpipwrres9 at acpi0: PIN_ acpipwrres10 at acpi0: PINP acpivideo0 at acpi0: GFX0 acpivout0 at acpivideo0: DD1F cpu0: Enhanced SpeedStep 1795 MHz: speeds: 2101, 2100, 1900, 1800, 1700, 1600, 1500, 1400, 1200, 1100, 1000, 800, 700, 600, 500, 400 MHz pci0 at mainbus0 bus 0 pchb0 at pci0 dev 0 function 0 "Intel Core 8G Host" rev 0x0c inteldrm0 at pci0 dev 2 function 0 "Intel UHD Graphics 620" rev 0x02 drm0 at inteldrm0 inteldrm0: msi, COFFEELAKE, gen 9 "Intel Core 6G Thermal" rev 0x0c at pci0 dev 4 function 0 not configured "Intel Core GMM" rev 0x00 at pci0 dev 8 function 0 not configured pchtemp0 at pci0 dev 18 function 0 "Intel 300 Series Thermal" rev 0x11 xhci0 at pci0 dev 20 function 0 "Intel 300 Series xHCI" rev 0x11: msi, xHCI 1.10 usb0 at xhci0: USB revision 3.0 uhub0 at usb0 configuration 1 interface 0 "Intel xHCI root hub" rev 3.00/1.00 addr 1 "Intel 300 Series Shared SRAM" rev 0x11 at pci0 dev 20 function 2 not configured iwm0 at pci0 dev 20 function 3 "Intel AC 9560" rev 0x11, msix dwiic0 at pci0 dev 21 function 0 "Intel 300 Series I2C" rev 0x11: apic 2 int 16 iic0 at dwiic0 dwiic1 at pci0 dev 21 function 1 "Intel 300 Series I2C" rev 0x11: apic 2 int 17 iic1 at dwiic1 ihidev0 at iic1 addr 0x2c gpio 100, vendor 0x6cb product 0xcd8b, SYNA8004 ihidev0: 15 report ids imt0 at ihidev0: clickpad, 5 contacts wsmouse0 at imt0 mux 0 ims0 at ihidev0 reportid 2: 2 buttons wsmouse1 at ims0 mux 0 hid at ihidev0 reportid 6 not configured hid at ihidev0 reportid 7 not configured hid at ihidev0 reportid 9 not configured hid at ihidev0 reportid 10 not configured hid at ihidev0 reportid 11 not configured hid at ihidev0 reportid 12 not configured hid at ihidev0 reportid 13 not configured hid at ihidev0 reportid 14 not configured hid at ihidev0 reportid 15 not configured "Intel 300 Series MEI" rev 0x11 at pci0 dev 22 function 0 not configured ppb0 at pci0 dev 29 function 0 "Intel 300 Series PCIE" rev 0xf1: msi pci1 at ppb0 bus 3 ...