[v3] riscv/mm/fault: add show_pte() before die()

[PATCH v3] riscv/mm/fault: add show_pte() before die()

Posted by Yunhui Cui 1 year, 4 months ago

When the kernel displays "Unable to handle kernel paging request at
virtual address", we would like to confirm the status of the virtual
address in the page table. So add show_pte() before die().

Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
---
 arch/riscv/mm/fault.c | 52 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index 5224f3733802..c72e6c7c09ef 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -22,6 +22,57 @@
 
 #include "../kernel/head.h"
 
+static void show_pte(unsigned long addr)
+{
+	pgd_t *pgdp, pgd;
+	p4d_t *p4dp, p4d;
+	pud_t *pudp, pud;
+	pmd_t *pmdp, pmd;
+	pte_t *ptep, pte;
+	struct mm_struct *mm = current->mm;
+
+	if (!mm)
+		mm = &init_mm;
+
+	pr_alert("Current %s pgtable: %luK pagesize, %d-bit VAs, pgdp=0x%016llx\n",
+		 current->comm, PAGE_SIZE / SZ_1K, VA_BITS,
+		 mm == &init_mm ? (u64)__pa_symbol(mm->pgd) : virt_to_phys(mm->pgd));
+
+	pgdp = pgd_offset(mm, addr);
+	pgd = pgdp_get(pgdp);
+	pr_alert("[%016lx] pgd=%016lx", addr, pgd_val(pgd));
+	if (pgd_none(pgd) || pgd_bad(pgd) || pgd_leaf(pgd))
+		goto out;
+
+	p4dp = p4d_offset(pgdp, addr);
+	p4d = p4dp_get(p4dp);
+	pr_cont(", p4d=%016lx", p4d_val(p4d));
+	if (p4d_none(p4d) || p4d_bad(p4d) || p4d_leaf(p4d))
+		goto out;
+
+	pudp = pud_offset(p4dp, addr);
+	pud = pudp_get(pudp);
+	pr_cont(", pud=%016lx", pud_val(pud));
+	if (pud_none(pud) || pud_bad(pud) || pud_leaf(pud))
+		goto out;
+
+	pmdp = pmd_offset(pudp, addr);
+	pmd = pmdp_get(pmdp);
+	pr_cont(", pmd=%016lx", pmd_val(pmd));
+	if (pmd_none(pmd) || pmd_bad(pmd) || pmd_leaf(pmd))
+		goto out;
+
+	ptep = pte_offset_map(pmdp, addr);
+	if (!ptep)
+		goto out;
+
+	pte = ptep_get(ptep);
+	pr_cont(", pte=%016lx", pte_val(pte));
+	pte_unmap(ptep);
+out:
+	pr_cont("\n");
+}
+
 static void die_kernel_fault(const char *msg, unsigned long addr,
 		struct pt_regs *regs)
 {
@@ -31,6 +82,7 @@ static void die_kernel_fault(const char *msg, unsigned long addr,
 		addr);
 
 	bust_spinlocks(0);
+	show_pte(addr);
 	die(regs, "Oops");
 	make_task_dead(SIGKILL);
 }
-- 
2.39.2

Re: [PATCH v3] riscv/mm/fault: add show_pte() before die()

Posted by yunhui cui 1 year, 4 months ago

Hi All,

A gentle ping, Any more comments on this patch?

On Tue, Jul 23, 2024 at 10:18 AM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
>
> When the kernel displays "Unable to handle kernel paging request at
> virtual address", we would like to confirm the status of the virtual
> address in the page table. So add show_pte() before die().
>
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> ---
>  arch/riscv/mm/fault.c | 52 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 52 insertions(+)
>
> diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
> index 5224f3733802..c72e6c7c09ef 100644
> --- a/arch/riscv/mm/fault.c
> +++ b/arch/riscv/mm/fault.c
> @@ -22,6 +22,57 @@
>
>  #include "../kernel/head.h"
>
> +static void show_pte(unsigned long addr)
> +{
> +       pgd_t *pgdp, pgd;
> +       p4d_t *p4dp, p4d;
> +       pud_t *pudp, pud;
> +       pmd_t *pmdp, pmd;
> +       pte_t *ptep, pte;
> +       struct mm_struct *mm = current->mm;
> +
> +       if (!mm)
> +               mm = &init_mm;
> +
> +       pr_alert("Current %s pgtable: %luK pagesize, %d-bit VAs, pgdp=0x%016llx\n",
> +                current->comm, PAGE_SIZE / SZ_1K, VA_BITS,
> +                mm == &init_mm ? (u64)__pa_symbol(mm->pgd) : virt_to_phys(mm->pgd));
> +
> +       pgdp = pgd_offset(mm, addr);
> +       pgd = pgdp_get(pgdp);
> +       pr_alert("[%016lx] pgd=%016lx", addr, pgd_val(pgd));
> +       if (pgd_none(pgd) || pgd_bad(pgd) || pgd_leaf(pgd))
> +               goto out;
> +
> +       p4dp = p4d_offset(pgdp, addr);
> +       p4d = p4dp_get(p4dp);
> +       pr_cont(", p4d=%016lx", p4d_val(p4d));
> +       if (p4d_none(p4d) || p4d_bad(p4d) || p4d_leaf(p4d))
> +               goto out;
> +
> +       pudp = pud_offset(p4dp, addr);
> +       pud = pudp_get(pudp);
> +       pr_cont(", pud=%016lx", pud_val(pud));
> +       if (pud_none(pud) || pud_bad(pud) || pud_leaf(pud))
> +               goto out;
> +
> +       pmdp = pmd_offset(pudp, addr);
> +       pmd = pmdp_get(pmdp);
> +       pr_cont(", pmd=%016lx", pmd_val(pmd));
> +       if (pmd_none(pmd) || pmd_bad(pmd) || pmd_leaf(pmd))
> +               goto out;
> +
> +       ptep = pte_offset_map(pmdp, addr);
> +       if (!ptep)
> +               goto out;
> +
> +       pte = ptep_get(ptep);
> +       pr_cont(", pte=%016lx", pte_val(pte));
> +       pte_unmap(ptep);
> +out:
> +       pr_cont("\n");
> +}
> +
>  static void die_kernel_fault(const char *msg, unsigned long addr,
>                 struct pt_regs *regs)
>  {
> @@ -31,6 +82,7 @@ static void die_kernel_fault(const char *msg, unsigned long addr,
>                 addr);
>
>         bust_spinlocks(0);
> +       show_pte(addr);
>         die(regs, "Oops");
>         make_task_dead(SIGKILL);
>  }
> --
> 2.39.2
>

Thanks,
Yunhui

Re: [PATCH v3] riscv/mm/fault: add show_pte() before die()

Posted by yunhui cui 1 year, 2 months ago

Hi Palmer,

A gentle ping for this patch.

On Thu, Aug 15, 2024 at 10:05 AM yunhui cui <cuiyunhui@bytedance.com> wrote:
>
> Hi All,
>
> A gentle ping, Any more comments on this patch?
>
> On Tue, Jul 23, 2024 at 10:18 AM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
> >
> > When the kernel displays "Unable to handle kernel paging request at
> > virtual address", we would like to confirm the status of the virtual
> > address in the page table. So add show_pte() before die().
> >
> > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> > Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> > Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> > ---
> >  arch/riscv/mm/fault.c | 52 +++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 52 insertions(+)
> >
> > diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
> > index 5224f3733802..c72e6c7c09ef 100644
> > --- a/arch/riscv/mm/fault.c
> > +++ b/arch/riscv/mm/fault.c
> > @@ -22,6 +22,57 @@
> >
> >  #include "../kernel/head.h"
> >
> > +static void show_pte(unsigned long addr)
> > +{
> > +       pgd_t *pgdp, pgd;
> > +       p4d_t *p4dp, p4d;
> > +       pud_t *pudp, pud;
> > +       pmd_t *pmdp, pmd;
> > +       pte_t *ptep, pte;
> > +       struct mm_struct *mm = current->mm;
> > +
> > +       if (!mm)
> > +               mm = &init_mm;
> > +
> > +       pr_alert("Current %s pgtable: %luK pagesize, %d-bit VAs, pgdp=0x%016llx\n",
> > +                current->comm, PAGE_SIZE / SZ_1K, VA_BITS,
> > +                mm == &init_mm ? (u64)__pa_symbol(mm->pgd) : virt_to_phys(mm->pgd));
> > +
> > +       pgdp = pgd_offset(mm, addr);
> > +       pgd = pgdp_get(pgdp);
> > +       pr_alert("[%016lx] pgd=%016lx", addr, pgd_val(pgd));
> > +       if (pgd_none(pgd) || pgd_bad(pgd) || pgd_leaf(pgd))
> > +               goto out;
> > +
> > +       p4dp = p4d_offset(pgdp, addr);
> > +       p4d = p4dp_get(p4dp);
> > +       pr_cont(", p4d=%016lx", p4d_val(p4d));
> > +       if (p4d_none(p4d) || p4d_bad(p4d) || p4d_leaf(p4d))
> > +               goto out;
> > +
> > +       pudp = pud_offset(p4dp, addr);
> > +       pud = pudp_get(pudp);
> > +       pr_cont(", pud=%016lx", pud_val(pud));
> > +       if (pud_none(pud) || pud_bad(pud) || pud_leaf(pud))
> > +               goto out;
> > +
> > +       pmdp = pmd_offset(pudp, addr);
> > +       pmd = pmdp_get(pmdp);
> > +       pr_cont(", pmd=%016lx", pmd_val(pmd));
> > +       if (pmd_none(pmd) || pmd_bad(pmd) || pmd_leaf(pmd))
> > +               goto out;
> > +
> > +       ptep = pte_offset_map(pmdp, addr);
> > +       if (!ptep)
> > +               goto out;
> > +
> > +       pte = ptep_get(ptep);
> > +       pr_cont(", pte=%016lx", pte_val(pte));
> > +       pte_unmap(ptep);
> > +out:
> > +       pr_cont("\n");
> > +}
> > +
> >  static void die_kernel_fault(const char *msg, unsigned long addr,
> >                 struct pt_regs *regs)
> >  {
> > @@ -31,6 +82,7 @@ static void die_kernel_fault(const char *msg, unsigned long addr,
> >                 addr);
> >
> >         bust_spinlocks(0);
> > +       show_pte(addr);
> >         die(regs, "Oops");
> >         make_task_dead(SIGKILL);
> >  }
> > --
> > 2.39.2
> >
>
> Thanks,
> Yunhui


Thanks,
Yunhui

Re: [PATCH v3] riscv/mm/fault: add show_pte() before die()

Posted by Punit Agrawal 1 year, 1 month ago

yunhui cui <cuiyunhui@bytedance.com> writes:

> Hi Palmer,
>
> A gentle ping for this patch.
>
> On Thu, Aug 15, 2024 at 10:05 AM yunhui cui <cuiyunhui@bytedance.com> wrote:
>>
>> Hi All,
>>
>> A gentle ping, Any more comments on this patch?
>>
>> On Tue, Jul 23, 2024 at 10:18 AM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
>> >
>> > When the kernel displays "Unable to handle kernel paging request at
>> > virtual address", we would like to confirm the status of the virtual
>> > address in the page table. So add show_pte() before die().
>> >
>> > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
>> > Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
>> > Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
>> > ---
>> >  arch/riscv/mm/fault.c | 52 +++++++++++++++++++++++++++++++++++++++++++
>> >  1 file changed, 52 insertions(+)

Another one that seems to have slipped through the cracks. If there are
no further comments, please merge the patch.

Thanks,
Punit

>> >
>> > diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
>> > index 5224f3733802..c72e6c7c09ef 100644
>> > --- a/arch/riscv/mm/fault.c
>> > +++ b/arch/riscv/mm/fault.c
>> > @@ -22,6 +22,57 @@
>> >
>> >  #include "../kernel/head.h"
>> >
>> > +static void show_pte(unsigned long addr)
>> > +{
>> > +       pgd_t *pgdp, pgd;
>> > +       p4d_t *p4dp, p4d;
>> > +       pud_t *pudp, pud;
>> > +       pmd_t *pmdp, pmd;
>> > +       pte_t *ptep, pte;
>> > +       struct mm_struct *mm = current->mm;
>> > +
>> > +       if (!mm)
>> > +               mm = &init_mm;
>> > +
>> > +       pr_alert("Current %s pgtable: %luK pagesize, %d-bit VAs, pgdp=0x%016llx\n",
>> > +                current->comm, PAGE_SIZE / SZ_1K, VA_BITS,
>> > +                mm == &init_mm ? (u64)__pa_symbol(mm->pgd) : virt_to_phys(mm->pgd));
>> > +
>> > +       pgdp = pgd_offset(mm, addr);
>> > +       pgd = pgdp_get(pgdp);
>> > +       pr_alert("[%016lx] pgd=%016lx", addr, pgd_val(pgd));
>> > +       if (pgd_none(pgd) || pgd_bad(pgd) || pgd_leaf(pgd))
>> > +               goto out;
>> > +
>> > +       p4dp = p4d_offset(pgdp, addr);
>> > +       p4d = p4dp_get(p4dp);
>> > +       pr_cont(", p4d=%016lx", p4d_val(p4d));
>> > +       if (p4d_none(p4d) || p4d_bad(p4d) || p4d_leaf(p4d))
>> > +               goto out;
>> > +
>> > +       pudp = pud_offset(p4dp, addr);
>> > +       pud = pudp_get(pudp);
>> > +       pr_cont(", pud=%016lx", pud_val(pud));
>> > +       if (pud_none(pud) || pud_bad(pud) || pud_leaf(pud))
>> > +               goto out;
>> > +
>> > +       pmdp = pmd_offset(pudp, addr);
>> > +       pmd = pmdp_get(pmdp);
>> > +       pr_cont(", pmd=%016lx", pmd_val(pmd));
>> > +       if (pmd_none(pmd) || pmd_bad(pmd) || pmd_leaf(pmd))
>> > +               goto out;
>> > +
>> > +       ptep = pte_offset_map(pmdp, addr);
>> > +       if (!ptep)
>> > +               goto out;
>> > +
>> > +       pte = ptep_get(ptep);
>> > +       pr_cont(", pte=%016lx", pte_val(pte));
>> > +       pte_unmap(ptep);
>> > +out:
>> > +       pr_cont("\n");
>> > +}
>> > +
>> >  static void die_kernel_fault(const char *msg, unsigned long addr,
>> >                 struct pt_regs *regs)
>> >  {
>> > @@ -31,6 +82,7 @@ static void die_kernel_fault(const char *msg, unsigned long addr,
>> >                 addr);
>> >
>> >         bust_spinlocks(0);
>> > +       show_pte(addr);
>> >         die(regs, "Oops");
>> >         make_task_dead(SIGKILL);
>> >  }
>> > --
>> > 2.39.2
>> >
>>
>> Thanks,
>> Yunhui
>
>
> Thanks,
> Yunhui