Re: [PATCH v3 1/2] ARM: ioremap: Sync PGDs for VMALLOC shadow

On 10/17/24 14:59, Linus Walleij wrote:

[...] +static unsigned long arm_kasan_mem_to_shadow(unsigned long addr) +{

• return (unsigned long)kasan_mem_to_shadow((void *)addr);

+}

`kasan_mem_to_shadow` function symbol is only exported with : CONFIG_KASAN_GENERIC or defined(CONFIG_KASAN_SW_TAGS) from kasan.h

To me, the if condition you added below should be expanded with those two macros.

[...] void __check_vmalloc_seq(struct mm_struct *mm) { int seq; do { seq = atomic_read(&init_mm.context.vmalloc_seq);

• memcpy(pgd_offset(mm, VMALLOC_START),
  

•        pgd_offset_k(VMALLOC_START),
  

•        sizeof(pgd_t) * (pgd_index(VMALLOC_END) -
  

• 			pgd_index(VMALLOC_START)));
  

• memcpy_pgd(mm, VMALLOC_START, VMALLOC_END);
  

• if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
  

• 	unsigned long start =
  

• 		arm_kasan_mem_to_shadow(VMALLOC_START);
  

• 	unsigned long end =
  

• 		arm_kasan_mem_to_shadow(VMALLOC_END);
  

• 	memcpy_pgd(mm, start, end);
  

• }
  

  /*
  • Use a store-release so that other CPUs that observe the
  • counter's new value are guaranteed to see the results of the

Otherwise it compiles with KASAN enabled, I am running some tests with your patches.

Regards,

Clément