There is a bug in create_safe_exec_page(), when page table is allocated it is not checked that table is allocated successfully:
But it is dereferenced in: pgd_none(READ_ONCE(*pgdp)). Another issue, is that phys_to_ttbr() uses an offset in page table instead of pgd directly. So, allocate page table, check that allocation was successful, and use it directly to set ttbr0_el1. Signed-off-by: Pavel Tatashin <[email protected]> --- arch/arm64/kernel/hibernate.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c index ee34a06d8a35..750ecc7f2cbe 100644 --- a/arch/arm64/kernel/hibernate.c +++ b/arch/arm64/kernel/hibernate.c @@ -199,6 +199,7 @@ static int create_safe_exec_page(void *src_start, size_t length, phys_addr_t *phys_dst_addr) { void *page = (void *)get_safe_page(GFP_ATOMIC); + pgd_t *trans_pgd; pgd_t *pgdp; pud_t *pudp; pmd_t *pmdp; @@ -210,7 +211,11 @@ static int create_safe_exec_page(void *src_start, size_t length, memcpy(page, src_start, length); __flush_icache_range((unsigned long)page, (unsigned long)page + length); - pgdp = pgd_offset_raw((void *)get_safe_page(GFP_ATOMIC), dst_addr); + trans_pgd = (void *)get_safe_page(GFP_ATOMIC); + if (!trans_pgd) + return -ENOMEM; + + pgdp = pgd_offset_raw(trans_pgd, dst_addr); if (pgd_none(READ_ONCE(*pgdp))) { pudp = (void *)get_safe_page(GFP_ATOMIC); if (!pudp) @@ -251,7 +256,7 @@ static int create_safe_exec_page(void *src_start, size_t length, */ cpu_set_reserved_ttbr0(); local_flush_tlb_all(); - write_sysreg(phys_to_ttbr(virt_to_phys(pgdp)), ttbr0_el1); + write_sysreg(phys_to_ttbr(virt_to_phys(trans_pgd)), ttbr0_el1); isb(); *phys_dst_addr = virt_to_phys(page); -- 2.23.0
