[PATCH 19/23] sparc: allow pte_offset_map() to fail

Hugh Dickins
2023-05-10T05:06:07Z

In rare transient cases, not yet made possible, pte_offset_map() and
pte_offset_map_lock() may not find a page table: handle appropriately.

Signed-off-by: Hugh Dickins <hughd@google.com>
---
arch/sparc/kernel/signal32.c | 2 ++
arch/sparc/mm/fault_64.c | 3 +++
arch/sparc/mm/tlb.c | 2 ++
3 files changed, 7 insertions(+)

diff --git a/arch/sparc/kernel/signal32.c b/arch/sparc/kernel/signal32.c
index dad38960d1a8..ca450c7bc53f 100644
--- a/arch/sparc/kernel/signal32.c
+++ b/arch/sparc/kernel/signal32.c
@@ -328,6 +328,8 @@ static void flush_signal_insns(unsigned long address)
goto out_irqs_on;

ptep = pte_offset_map(pmdp, address);
+ if (!ptep)
+ goto out_irqs_on;
pte = *ptep;
if (!pte_present(pte))
goto out_unmap;
diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c
index d91305de694c..d8a407fbe350 100644
--- a/arch/sparc/mm/fault_64.c
+++ b/arch/sparc/mm/fault_64.c
@@ -99,6 +99,7 @@ static unsigned int get_user_insn(unsigned long tpc)
local_irq_disable();

pmdp = pmd_offset(pudp, tpc);
+again:
if (pmd_none(*pmdp) || unlikely(pmd_bad(*pmdp)))
goto out_irq_enable;

@@ -115,6 +116,8 @@ static unsigned int get_user_insn(unsigned long tpc)
#endif
{
ptep = pte_offset_map(pmdp, tpc);
+ if (!ptep)
+ goto again;
pte = *ptep;
if (pte_present(pte)) {
pa = (pte_pfn(pte) << PAGE_SHIFT);
diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index 9a725547578e..7ecf8556947a 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -149,6 +149,8 @@ static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr,
pte_t *pte;

pte = pte_offset_map(&pmd, vaddr);
+ if (!pte)
+ return;
end = vaddr + HPAGE_SIZE;
while (vaddr < end) {
if (pte_val(*pte) & _PAGE_VALID) {
--
2.35.3