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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 9354520008 X-Stat-Signature: bs9bca9khme6rjy3qhsfg54485py98fu X-HE-Tag: 1759214496-344672 X-HE-Meta: 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 PUYocVtN 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 30.09.25 06:37, Dev Jain wrote: > > On 30/09/25 8:22 am, Anshuman Khandual wrote: >> Replace READ_ONCE() with standard page table accessors i.e pxdp_get() which >> anyways default into READ_ONCE() in cases where platform does not override. >> >> Cc: Andrew Morton >> Cc: David Hildenbrand >> Cc: linux-mm@kvack.org >> Cc: linux-kernel@vger.kernel.org >> Signed-off-by: Anshuman Khandual >> --- >> mm/ptdump.c | 8 ++++---- >> 1 file changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/mm/ptdump.c b/mm/ptdump.c >> index b600c7f864b8..18861501b533 100644 >> --- a/mm/ptdump.c >> +++ b/mm/ptdump.c >> @@ -31,7 +31,7 @@ static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr, >> unsigned long next, struct mm_walk *walk) >> { >> struct ptdump_state *st = walk->private; >> - pgd_t val = READ_ONCE(*pgd); >> + pgd_t val = pgdp_get(pgd); >> >> #if CONFIG_PGTABLE_LEVELS > 4 && \ >> (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) >> @@ -54,7 +54,7 @@ static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr, >> unsigned long next, struct mm_walk *walk) >> { >> struct ptdump_state *st = walk->private; >> - p4d_t val = READ_ONCE(*p4d); >> + p4d_t val = p4dp_get(p4d); >> >> #if CONFIG_PGTABLE_LEVELS > 3 && \ >> (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) >> @@ -77,7 +77,7 @@ static int ptdump_pud_entry(pud_t *pud, unsigned long addr, >> unsigned long next, struct mm_walk *walk) >> { >> struct ptdump_state *st = walk->private; >> - pud_t val = READ_ONCE(*pud); >> + pud_t val = pudp_get(pud); >> >> #if CONFIG_PGTABLE_LEVELS > 2 && \ >> (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) >> @@ -100,7 +100,7 @@ static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr, >> unsigned long next, struct mm_walk *walk) >> { >> struct ptdump_state *st = walk->private; >> - pmd_t val = READ_ONCE(*pmd); >> + pmd_t val = pmdp_get(pmd); > > I believe this should go through pmdp_get_lockless(). I can see in pgtable.h that > some magic is required on some arches to decode the pmd correctly in case walking > without locks. pmdp_get_lockless() is a nasty thingy to handle selected 32bit architectures. But given that we're using ptep_get_lockless() in ptdump_pmd_entry() it probably wouldn't hurt to use pmdp_get_lockless() here. Staring at ARCH_HAS_PTDUMP, I don't think any 32bit arch would actually end up compiling ptdump.c. E.g., on x86 only X86_64 ends up selecting ARCH_HAS_PTDUMP. -- Cheers David / dhildenb