On 09/02/2020 05:12 PM, Aneesh Kumar K.V wrote:
> This will help in adding proper locks in a later patch
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
> ---
> mm/debug_vm_pgtable.c | 51 ++++++++++++++++++++++++-------------------
> 1 file changed, 28 insertions(+), 23 deletions(-)
>
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index de333871f407..f59cf6a9b05e 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -986,7 +986,7 @@ static int __init debug_vm_pgtable(void)
> p4dp = p4d_alloc(mm, pgdp, vaddr);
> pudp = pud_alloc(mm, p4dp, vaddr);
> pmdp = pmd_alloc(mm, pudp, vaddr);
> - ptep = pte_alloc_map_lock(mm, pmdp, vaddr, &ptl);
> + ptep = pte_alloc_map(mm, pmdp, vaddr);
>
> /*
> * Save all the page table page addresses as the page table
> @@ -1006,33 +1006,12 @@ static int __init debug_vm_pgtable(void)
> p4d_basic_tests(p4d_aligned, prot);
> pgd_basic_tests(pgd_aligned, prot);
>
> - pte_clear_tests(mm, ptep, vaddr);
> - pmd_clear_tests(mm, pmdp);
> - pud_clear_tests(mm, pudp);
> - p4d_clear_tests(mm, p4dp);
> - pgd_clear_tests(mm, pgdp);
> -
> - pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
> - pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot);
> - pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot);
> - hugetlb_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
> -
> pmd_leaf_tests(pmd_aligned, prot);
> pud_leaf_tests(pud_aligned, prot);
>
> - pmd_huge_tests(pmdp, pmd_aligned, prot);
> - pud_huge_tests(pudp, pud_aligned, prot);
> -
> pte_savedwrite_tests(pte_aligned, protnone);
> pmd_savedwrite_tests(pmd_aligned, protnone);
>
> - pte_unmap_unlock(ptep, ptl);
> -
> - pmd_populate_tests(mm, pmdp, saved_ptep);
> - pud_populate_tests(mm, pudp, saved_pmdp);
> - p4d_populate_tests(mm, p4dp, saved_pudp);
> - pgd_populate_tests(mm, pgdp, saved_p4dp);
> -
> pte_special_tests(pte_aligned, prot);
> pte_protnone_tests(pte_aligned, protnone);
> pmd_protnone_tests(pmd_aligned, protnone);
> @@ -1050,11 +1029,37 @@ static int __init debug_vm_pgtable(void)
> pmd_swap_tests(pmd_aligned, prot);
>
> swap_migration_tests();
> - hugetlb_basic_tests(pte_aligned, prot);
>
> pmd_thp_tests(pmd_aligned, prot);
> pud_thp_tests(pud_aligned, prot);
>
> + hugetlb_basic_tests(pte_aligned, prot);
> +
> + pte_clear_tests(mm, ptep, vaddr);
> + pmd_clear_tests(mm, pmdp);
> + pud_clear_tests(mm, pudp);
> + p4d_clear_tests(mm, p4dp);
> + pgd_clear_tests(mm, pgdp);
> +
> + ptl = pte_lockptr(mm, pmdp);
> + spin_lock(ptl);
> +
> + pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
> + pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot);
> + pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot);
> + hugetlb_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
> +
> +
> + pmd_huge_tests(pmdp, pmd_aligned, prot);
> + pud_huge_tests(pudp, pud_aligned, prot);
> +
> + pte_unmap_unlock(ptep, ptl);
> +
> + pmd_populate_tests(mm, pmdp, saved_ptep);
> + pud_populate_tests(mm, pudp, saved_pmdp);
> + p4d_populate_tests(mm, p4dp, saved_pudp);
> + pgd_populate_tests(mm, pgdp, saved_p4dp);
> +
> p4d_free(mm, saved_p4dp);
> pud_free(mm, saved_pudp);
> pmd_free(mm, saved_pmdp);
>
Patches applied till here [i.e PATCH_1..PATCH_8] does not boot on arm64
platform, which might create a potential git bisect problem later on.
static void __init pte_advanced_tests(struct mm_struct *mm,
struct vm_area_struct *vma, pte_t *ptep,
unsigned long pfn, unsigned long vaddr,
pgprot_t prot)
{
pte_t pte = pfn_pte(pfn, prot);
/*
* Architectures optimize set_pte_at by avoiding TLB flush.
* This requires set_pte_at to be not used to update an
* existing pte entry. Clear pte before we do set_pte_at
*/
pr_debug("Validating PTE advanced\n");
pte = pfn_pte(pfn, prot);
set_pte_at(mm, vaddr, ptep, pte); ----------> Crashed here.
............
............
[ 19.031831] Unable to handle kernel paging request at virtual address fffffdfffde00028
[ 19.033181] Mem abort info:
[ 19.033627] ESR = 0x96000006
[ 19.034129] EC = 0x25: DABT (current EL), IL = 32 bits
[ 19.035002] SET = 0, FnV = 0
[ 19.035523] EA = 0, S1PTW = 0
[ 19.036054] Data abort info:
[ 19.036538] ISV = 0, ISS = 0x00000006
[ 19.037170] CM = 0, WnR = 0
[ 19.037662] swapper pgtable: 4k pages, 48-bit VAs, pgdp=000000008158b000
[ 19.038749] [fffffdfffde00028] pgd=0000000081d69003, p4d=0000000081d69003, pud=0000000081d6a003, pmd=0000000000000000
[ 19.040560] Internal error: Oops: 96000006 [#1] PREEMPT SMP
[ 19.041467] Modules linked in:
[ 19.041968] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 5.9.0-rc3-00231-gdef09f62540f #62
[ 19.043472] Hardware name: linux,dummy-virt (DT)
[ 19.044292] pstate: 20400005 (nzCv daif +PAN -UAO BTYPE=--)
[ 19.045235] pc : _raw_spin_lock+0x34/0x70
[ 19.045944] lr : debug_vm_pgtable+0x3c8/0x8b8
[ 19.046713] sp : ffff80001219bcf0
[ 19.047295] x29: ffff80001219bcf0 x28: ffff8000114ac000
[ 19.048224] x27: ffff0005df61f080 x26: ffff8000114ac000
[ 19.049148] x25: 0020000000000fd3 x24: 0020000081400fd3
[ 19.050076] x23: 00003df483b17000 x22: ffff0005ddd63e90
[ 19.051011] x21: ffff0005dddc8000 x20: ffff0005ddd5f0e8
[ 19.051937] x19: ffff0005de3718b8 x18: 0000000000000010
[ 19.052846] x17: 00000000dbb99b48 x16: 00000000cc138a43
[ 19.053774] x15: 0000000000000001 x14: 0000000000000002
[ 19.054703] x13: 000000000055e46d x12: fffffe0017577200
[ 19.055630] x11: 0000000000000008 x10: ffff0005fc455210
[ 19.056553] x9 : ffff0005fc455210 x8 : 0000000000000010
[ 19.057484] x7 : ffff8005ead60000 x6 : ffff0005fcfcee00
[ 19.058410] x5 : ffff0005fc455200 x4 : 0000000000000000
[ 19.059344] x3 : fffffdfffde00028 x2 : 0000000000000001
[ 19.060272] x1 : 0000000000000000 x0 : fffffdfffde00028
[ 19.061203] Call trace:
[ 19.061644] _raw_spin_lock+0x34/0x70
[ 19.062289] debug_vm_pgtable+0x3c8/0x8b8
[ 19.063001] do_one_initcall+0x74/0x1cc
[ 19.063680] kernel_init_freeable+0x1d0/0x238
[ 19.064448] kernel_init+0x14/0x118
[ 19.065067] ret_from_fork+0x10/0x34
[ 19.065703] Code: d503201f 52800001 52800022 2a0103e4 (88e47c02)
[ 19.066835] ---[ end trace ff33eeb13d2a13af ]---
