Hi Hugh,
Thanks for your patch!
On Wed, May 10, 2023 at 6:48 AM Hugh Dickins <hughd@xxxxxxxxxx> wrote:
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offset_map_lock() may not find a page table: handle appropriately.
Restructure cf_tlb_miss() with a pte_unmap() (previously omitted)
at label out, followed by one local_irq_restore() for all.
That's a bug fix, which should be a separate patch?
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
--- a/arch/m68k/include/asm/mmu_context.h
+++ b/arch/m68k/include/asm/mmu_context.h
@@ -99,7 +99,7 @@ static inline void load_ksp_mmu(struct task_struct *task)
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
- pte_t *pte;
+ pte_t *pte = NULL;
unsigned long mmuar;
local_irq_save(flags);
@@ -139,7 +139,7 @@ static inline void load_ksp_mmu(struct task_struct *task)
pte = (mmuar >= PAGE_OFFSET) ? pte_offset_kernel(pmd, mmuar)
: pte_offset_map(pmd, mmuar);
- if (pte_none(*pte) || !pte_present(*pte))
+ if (!pte || pte_none(*pte) || !pte_present(*pte))
goto bug;
If the absence of a pte is to become a non-abnormal case, it should
probably jump to "end" instead, to avoid spamming the kernel log.
set_pte(pte, pte_mkyoung(*pte));
@@ -161,6 +161,8 @@ static inline void load_ksp_mmu(struct task_struct *task)
bug:
pr_info("ksp load failed: mm=0x%p ksp=0x08%lx\n", mm, mmuar);
end:
+ if (pte && mmuar < PAGE_OFFSET)
+ pte_unmap(pte);
Is this also a bugfix, not mentioned in the patch description?
local_irq_restore(flags);
}
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
