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However, vm_area_register_early() assumes the use of the global _vmlist_ structure before vmalloc_init() is invoked. This assumption can lead to issues during early boot. See the calltrace as follows: start_kernel() setup_per_cpu_areas() pcpu_page_first_chunk() vm_area_register_early() mm_core_init() vmalloc_init() The early vm areas will be added to vmlist at declare_kernel_vmas() ->declare_vma(): ffff800080010000 T _stext ffff800080da0000 D __start_rodata ffff800081890000 T __inittext_begin ffff800081980000 D __initdata_begin ffff800081ee0000 D _data The starting address of the early areas is tied to the *old* VMALLOC_START (i.e. 0xffff800080000000 on an arm64 N2 server). If VMALLOC_START is redefined, it can disrupt early VM area allocation, particularly in like pcpu_page_first_chunk()->vm_area_register_early(). To address this potential risk on arm64, introduce a new boundary, VMALLOC_EARLY_START, to avoid boot issues when VMALLOC_START is occasionaly redefined. Signed-off-by: Jia He --- arch/arm64/include/asm/pgtable.h | 2 ++ mm/vmalloc.c | 6 +++++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 192d86e1cc76..91031912a906 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -18,9 +18,11 @@ * VMALLOC range. * * VMALLOC_START: beginning of the kernel vmalloc space + * VMALLOC_EARLY_START: early vm area before vmalloc_init() * VMALLOC_END: extends to the available space below vmemmap */ #define VMALLOC_START (MODULES_END) +#define VMALLOC_EARLY_START (MODULES_END) #if VA_BITS == VA_BITS_MIN #define VMALLOC_END (VMEMMAP_START - SZ_8M) #else diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 6dbcdceecae1..86ab1e99641a 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -50,6 +50,10 @@ #include "internal.h" #include "pgalloc-track.h" +#ifndef VMALLOC_EARLY_START +#define VMALLOC_EARLY_START VMALLOC_START +#endif + #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP static unsigned int __ro_after_init ioremap_max_page_shift = BITS_PER_LONG - 1; @@ -3126,7 +3130,7 @@ void __init vm_area_add_early(struct vm_struct *vm) */ void __init vm_area_register_early(struct vm_struct *vm, size_t align) { - unsigned long addr = ALIGN(VMALLOC_START, align); + unsigned long addr = ALIGN(VMALLOC_EARLY_START, align); struct vm_struct *cur, **p; BUG_ON(vmap_initialized); -- 2.34.1