Package: linux Version: 4.19.37 A kernel panic occurs when attempting to boot Debian 10.1.0 (32-bit) on an Intel Atom C3958 processor. https://ark.intel.com/content/www/us/en/ark/products/97927/intel-atom-processor-c3958-16m-cache-up-to-2-0-ghz.html
The hardware I'm using is this board: https://www.dfi.com/product/index/149 (rev 3), with carrier board https://www.dfi.com/product/index/223 (rev 3.0). When booting the system, the following panic occurs: [ 2.457743] Kernel panic - not syncing: BIOS has enabled x2apic but kernel doesn't support x2apic, please disable x2apic in BIOS. [ 2.457743] [ 2.457743] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-6-686-pae #1 Debian 4.19.67-2+deb10u1 [ 2.457743] Hardware name: /DV970, BIOS B193.25A 03/25/2019 [ 2.457743] Call Trace: [ 2.457743] dump_stack+0x58/0x7e [ 2.457743] ? apic_verify+0xab/0xab [ 2.457743] panic+0x94/0x1e0 [ 2.457743] ? apic_verify+0xab/0xab [ 2.457743] ? apic_verify+0xab/0xab [ 2.457743] validate_x2apic+0x4d/0x4f [ 2.457743] do_one_initcall+0x42/0x19a [ 2.457743] ? proc_register+0xab/0x110 [ 2.457743] ? proc_create_seq_private+0x3e/0x40 [ 2.457743] ? init_mm_internals+0x181/0x18b [ 2.457743] kernel_init_freeable+0xb0/0x1e0 [ 2.457743] ? rest_init+0x8a/0x8a [ 2.457743] kernel_init+0xd/0xea [ 2.457743] ret_from_fork+0x2e/0x38 [ 2.457743] ---[ end Kernel panic - not syncing: BIOS has enabled x2apic but kernel doesn't support x2apic, please disable x2apic in BIOS. [ 2.457743] ]--- There is no option to disable APIC in the board BIOS. When attempting to boot without APIC enabled, the panic still occurs: [ 0.202575] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.19.0-6-686-pae root=UUID=3d4351e7-53e9-4d65-8a81-c205f3cd7a6e ro quiet console=tty console=ttyS1,115200 noapic nox2apic noioapic debug apic=debug show_lapic=all ... [ 2.944990] Kernel panic - not syncing: BIOS has enabled x2apic but kernel doesn't support x2apic, please disable x2apic in BIOS. [ 2.944990] [ 2.944990] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-6-686-pae #1 Debian 4.19.67-2+deb10u1 [ 2.944990] Hardware name: /DV970, BIOS B193.25A 03/25/2019 [ 2.944990] Call Trace: [ 2.944990] dump_stack+0x58/0x7e [ 2.944990] ? apic_verify+0xab/0xab [ 2.944990] panic+0x94/0x1e0 [ 2.944990] ? apic_verify+0xab/0xab [ 2.944990] ? apic_verify+0xab/0xab [ 2.944990] validate_x2apic+0x4d/0x4f [ 2.944990] do_one_initcall+0x42/0x19a [ 2.944990] ? proc_register+0xab/0x110 [ 2.944990] ? proc_create_seq_private+0x3e/0x40 [ 2.944990] ? init_mm_internals+0x181/0x18b [ 2.944990] kernel_init_freeable+0xb0/0x1e0 [ 2.944990] ? rest_init+0x8a/0x8a [ 2.944990] kernel_init+0xd/0xea [ 2.944990] ret_from_fork+0x2e/0x38 [ 2.944990] ---[ end Kernel panic - not syncing: BIOS has enabled x2apic but kernel doesn't support x2apic, please disable x2apic in BIOS. [ 2.944990] ]--- When booting with the kernel parameters "acpi=off noapic nosmp forcepae", the panic message changes: [ 0.201640] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.19.0-6-686-pae root=UUID=3d4351e7-53e9-4d65-8a81-c205f3cd7a6e ro quiet console=tty console=ttyS1,115200 debug acpi=off noapic nosmp forcepae ... [ 2.025480] ------------[ cut here ]------------ [ 2.030212] kernel BUG at arch/x86/kernel/apic/apic.c:1500! [ 2.035919] invalid opcode: 0000 [#1] SMP NOPTI [ 2.040571] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.19.0-6-686-pae #1 Debian 4.19.67-2+deb10u1 [ 2.049675] Hardware name: /DV970, BIOS B193.25A 03/25/2019 [ 2.055456] EIP: setup_local_APIC+0x4a0/0x510 [ 2.059929] Code: 00 eb 84 8d b4 26 00 00 00 00 a1 80 f7 85 c8 ba 00 04 00 00 8b 48 08 b8 60 03 00 00 e8 41 36 65 00 e9 07 fe ff ff 8d 74 26 00 <0f> 0b 8d b6 00 00 00 00 a1 cc 6d a5 c8 0b 05 a4 6e a5 c8 0f 85 8d [ 2.078893] EAX: 00000000 EBX: 00000000 ECX: c8a5fde4 EDX: fffff000 [ 2.085276] ESI: c89b6948 EDI: f6ffc568 EBP: c88abf54 ESP: c88abf24 [ 2.091665] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210246 [ 2.098573] CR0: 80050033 CR2: ff9ff000 CR3: 08a48000 CR4: 000406b0 [ 2.104959] Call Trace: [ 2.107524] ? vprintk_default+0x17/0x20 [ 2.111566] apic_bsp_setup+0x81/0x97 [ 2.115342] apic_intr_mode_init+0x1a6/0x1ab [ 2.119729] x86_late_time_init+0x16/0x1d [ 2.123853] start_kernel+0x3a3/0x45f [ 2.127630] i386_start_kernel+0xac/0xb0 [ 2.131672] startup_32_smp+0x164/0x168 [ 2.135623] Modules linked in: [ 2.138811] ---[ end trace 2d2c9d5d7faf9f9e ]--- [ 2.143560] EIP: setup_local_APIC+0x4a0/0x510 [ 2.148049] Code: 00 eb 84 8d b4 26 00 00 00 00 a1 80 f7 85 c8 ba 00 04 00 00 8b 48 08 b8 60 03 00 00 e8 41 36 65 00 e9 07 fe ff ff 8d 74 26 00 <0f> 0b 8d b6 00 00 00 00 a1 cc 6d a5 c8 0b 05 a4 6e a5 c8 0f 85 8d [ 2.167032] EAX: 00000000 EBX: 00000000 ECX: c8a5fde4 EDX: fffff000 [ 2.173432] ESI: c89b6948 EDI: f6ffc568 EBP: c88abf54 ESP: c8a4fdfc [ 2.179827] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210246 [ 2.186745] CR0: 80050033 CR2: ff9ff000 CR3: 08a48000 CR4: 000406b0 [ 2.193150] Kernel panic - not syncing: Attempted to kill the idle task! [ 2.199986] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- I am using Debian GNU/Linux 10.1.0 (i386 netinstall image) from https://cdimage.debian.org/debian-cd/current/i386/iso-cd/debian-10.1.0-i386-netinst.iso I am not sure what the cause of the issue is, but I have the following suspicions: - in /arch/x86/kernel/apic/apic.c, apic_verify(), https://elixir.bootlin.com/linux/v4.19.37/source/arch/x86/kernel/apic/apic.c#L1848, appears to be the source of the kernel panic message. There may be an issue with the MSR reads and bitmasking in the function due to 32- vs 64-bit alignment. - There is a question/comment in the linux-4.19.37 code, https://elixir.bootlin.com/linux/v4.19.37/source/arch/x86/kernel/apic/apic.c#L1903, which suggests that the "noapic" kernel parameter might not be affecting kernel behaviour. Please let me know if there is additional information I can provide. Regards, Matt
