[PATCH v4 0/2] memblock: make memblock_find_in_range method private

Thu Aug 12 07:40:01 PDT 2021

Mike,

On Thu, Aug 12, 2021 at 09:59:05AM +0300, Mike Rapoport wrote:
> From: Mike Rapoport <rppt at linux.ibm.com>
> 
> Hi,
> 
> This is v4 of "memblock: make memblock_find_in_range method private" patch
> that essentially replaces memblock_find_in_range() + memblock_reserve()
> calls with equivalent calls to memblock_phys_alloc() and prevents usage of
> memblock_find_in_range() outside memblock itself.
> 
> The patch uncovered an issue with top down memory mapping on x86 and this
> version has a preparation patch that addresses this issue.
> 
> Guenter, I didn't add your Tested-by because the patch that addresses the
> crashes differs from the one you've tested.
> 

Unfortunately I am still seeing crashes.

1G of memory, x86_64:

[    0.000000] efi: EFI v2.70 by EDK II
[    0.000000] efi: SMBIOS=0x3fbcc000 ACPI=0x3fbfa000 ACPI 2.0=0x3fbfa014 MEMATTR=0x3f229018 
[    0.000000] SMBIOS 2.8 present.
[    0.000000] DMI: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[    0.000000] tsc: Fast TSC calibration using PIT
[    0.000000] tsc: Detected 3792.807 MHz processor
[    0.001816] last_pfn = 0x3ff50 max_arch_pfn = 0x400000000
[    0.002595] x86/PAT: Configuration [0-7]: WB  WC  UC- UC  WB  WP  UC- WT  
[    0.022989] Using GB pages for direct mapping
[    0.025601] Kernel panic - not syncing: alloc_low_pages: can not alloc memory
[    0.025910] CPU: 0 PID: 0 Comm: swapper Not tainted 5.14.0-rc5+ #1
[    0.026133] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[    0.026462] Call Trace:
[    0.026942]  ? dump_stack_lvl+0x57/0x7d
[    0.027475]  ? panic+0x10a/0x2de
[    0.027600]  ? alloc_low_pages+0x117/0x156
[    0.027704]  ? phys_pmd_init+0x234/0x342
[    0.027817]  ? phys_pud_init+0x171/0x337
[    0.027926]  ? __kernel_physical_mapping_init+0xec/0x276
[    0.028062]  ? init_memory_mapping+0x1ea/0x2ca
[    0.028199]  ? init_range_memory_mapping+0xdf/0x12e
[    0.028326]  ? init_mem_mapping+0x1e9/0x261
[    0.028432]  ? setup_arch+0x5ff/0xb6d
[    0.028535]  ? start_kernel+0x71/0x6b4
[    0.028636]  ? secondary_startup_64_no_verify+0xc2/0xcb
[    0.029479] ---[ end Kernel panic - not syncing: alloc_low_pages: can not alloc memory ]---

Complete log:
https://kerneltests.org/builders/qemu-x86_64-testing/builds/67/steps/qemubuildcommand/logs/stdio

x86, default memory size, all efi boots affected:

[    0.025676] BUG: unable to handle page fault for address: cf3c1000
[    0.025932] #PF: supervisor write access in kernel mode
[    0.026022] #PF: error_code(0x0002) - not-present page
[    0.026122] *pde = 00000000
[    0.026308] Oops: 0002 [#1] SMP
[    0.026468] CPU: 0 PID: 0 Comm: swapper Not tainted 5.14.0-rc5+ #1
[    0.026616] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[    0.026848] EIP: alloc_low_pages+0xa0/0x13f
[    0.027355] Code: 00 74 77 a3 cc ba 62 ca 8b 45 f0 8d 90 00 00 0c 00 31 c0 c1 e2 0c 85 f6 74 16 89 d7 b9 00 04 00 00 83 c3 01 81 c2 00 10 00 00 <f3> ab 39 f3 75 ea 8b 45 f0 8d 65 f4 5b 5e c1 e0 0c 5f 5d 2d 00 00
[    0.027802] EAX: 00000000 EBX: 00000001 ECX: 00000400 EDX: cf3c2000
[    0.027903] ESI: 00000001 EDI: cf3c1000 EBP: ca389e28 ESP: ca389e18
[    0.028006] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00200086
[    0.028125] CR0: 80050033 CR2: cf3c1000 CR3: 0a69f000 CR4: 00040690
[    0.028287] Call Trace:
[    0.028603]  one_page_table_init+0x15/0x6d
[    0.028751]  kernel_physical_mapping_init+0xdd/0x19b
[    0.028839]  init_memory_mapping+0x146/0x1f1
[    0.028921]  init_range_memory_mapping+0xfe/0x144
[    0.029001]  init_mem_mapping+0x145/0x185
[    0.029066]  setup_arch+0x5ff/0xa75
[    0.029128]  ? vprintk+0x4c/0x100
[    0.029187]  start_kernel+0x66/0x5ba
[    0.029246]  ? set_intr_gate+0x42/0x55
[    0.029306]  ? early_idt_handler_common+0x44/0x44
[    0.029380]  i386_start_kernel+0x43/0x45
[    0.029441]  startup_32_smp+0x161/0x164
[    0.029567] Modules linked in:
[    0.029776] CR2: 00000000cf3c1000
[    0.030406] random: get_random_bytes called from oops_exit+0x35/0x60 with crng_init=0
[    0.031121] ---[ end trace 544692cd05e387e2 ]---
[    0.031357] EIP: alloc_low_pages+0xa0/0x13f
[    0.031427] Code: 00 74 77 a3 cc ba 62 ca 8b 45 f0 8d 90 00 00 0c 00 31 c0 c1 e2 0c 85 f6 74 16 89 d7 b9 00 04 00 00 83 c3 01 81 c2 00 10 00 00 <f3> ab 39 f3 75 ea 8b 45 f0 8d 65 f4 5b 5e c1 e0 0c 5f 5d 2d 00 00
[    0.031698] EAX: 00000000 EBX: 00000001 ECX: 00000400 EDX: cf3c2000
[    0.031787] ESI: 00000001 EDI: cf3c1000 EBP: ca389e28 ESP: ca389e18
[    0.031876] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00200086
[    0.031972] CR0: 80050033 CR2: cf3c1000 CR3: 0a69f000 CR4: 00040690
[    0.032198] Kernel panic - not syncing: Attempted to kill the idle task!
[    0.032521] ---[ end Kernel panic - not syncing: Attempted to kill the idle
task! ]--

Complete log: 
https://kerneltests.org/builders/qemu-x86-testing/builds/65/steps/qemubuildcommand/logs/stdio

Guenter