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charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 X-Rspamd-Server: rspam01 X-Stat-Signature: jwyrjfcz5zy5cruc7jq4c6i8jz1ap8ci X-Rspam-User: X-Rspamd-Queue-Id: 38C12140016 X-HE-Tag: 1743518090-477685 X-HE-Meta: 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 4YaIQqyg XCvyN3584pn629P+QinaoTo4P5lTGWOAFKT52hdjcSoH1ijIyKrZAM/Y7up8wHHyAC1MhBA6lXxsquHwZY/+7+y+CI/bPI4QscEUXaCCt+Q1STbUo2/5W6xK6XU/DYx3a77/WY3HxD+jPM4oSLXt17bU82zDK5ldOxgbsFJi6GY5SrXYTYIqCU2aDkCR9859/Ite8JWkDXblZippn6TkhlxYNrHtYChIOnxzsCQnsJIz6EtN1hV35P6Lzkj4iDCqaYGSnyN+byKL5rT4a2rANyKjcHPiuWS/qtrW3VDQaAhmjWsF83xtfGlbWVSSsRNpImVj+njsWwJwkJVXhNBgcMowgpiXyxJuMFEw7JfLCKO0b2mqClGk4kaFaqxL2jM5fjdgT7xkkfVOHFfdZA3PxXE+zwgOYV2FhhHLl7a6e2IHclxnX/jSwBDsIXjAxwfVq57lHLuLJJKNXGJX3tAnrGFMmt2vVmS3Pi6tF 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 04/01/25 at 10:02am, David Hildenbrand wrote: > On 31.03.25 10:13, Baoquan He wrote: > > In __get_user_pages(), it will traverse page table and take a reference > > to the page the given user address corresponds to if GUP_GET or GUP_PIN > > is et. However, it's not supported both GUP_GET and GUP_PIN are set. > > This check should be done earlier, but not doing it till entering into > > follow_page_pte() and failed. > > > > Here move the checking to the beginning of __get_user_pages(). > > > > Signed-off-by: Baoquan He > > --- > > v1->v2: > > - Fix code bug caused by copy-and-paste error, this is reported by > > lkp test robot. > > > > mm/gup.c | 10 +++++----- > > 1 file changed, 5 insertions(+), 5 deletions(-) > > > > diff --git a/mm/gup.c b/mm/gup.c > > index 73777b1de679..f9bce14ed3cd 100644 > > --- a/mm/gup.c > > +++ b/mm/gup.c > > @@ -847,11 +847,6 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, > > pte_t *ptep, pte; > > int ret; > > - /* FOLL_GET and FOLL_PIN are mutually exclusive. */ > > - if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == > > - (FOLL_PIN | FOLL_GET))) > > - return ERR_PTR(-EINVAL); > > - > > ptep = pte_offset_map_lock(mm, pmd, address, &ptl); > > if (!ptep) > > return no_page_table(vma, flags, address); > > @@ -1434,6 +1429,11 @@ static long __get_user_pages(struct mm_struct *mm, > > VM_BUG_ON(!!pages != !!(gup_flags & (FOLL_GET | FOLL_PIN))); > > + /* FOLL_GET and FOLL_PIN are mutually exclusive. */ > > + if (WARN_ON_ONCE((gup_flags & (FOLL_PIN | FOLL_GET)) == > > + (FOLL_PIN | FOLL_GET))) > > + return -EINVAL; > > + > > We already have that check in is_valid_gup_args(), that catches all external > users that could possibly mess this up. Right. > > So we can just convert that into a VM_WARN_ON_ONCE(), and while doing that, > we should convert the VM_BUG_ON() above to a VM_WARN_ON_ONCE() as well. Sounds great to me, will put below change into this patch of v3 as suggested. Thanks. diff --git a/mm/gup.c b/mm/gup.c index 9e4ed09c578b..d551da9549b1 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1427,10 +1427,10 @@ static long __get_user_pages(struct mm_struct *mm, start = untagged_addr_remote(mm, start); - VM_BUG_ON(!!pages != !!(gup_flags & (FOLL_GET | FOLL_PIN))); + VM_WARN_ON_ONCE(!!pages != !!(gup_flags & (FOLL_GET | FOLL_PIN))); /* FOLL_GET and FOLL_PIN are mutually exclusive. */ - if (WARN_ON_ONCE((gup_flags & (FOLL_PIN | FOLL_GET)) == + if (VM_WARN_ON_ONCE((gup_flags & (FOLL_PIN | FOLL_GET)) == (FOLL_PIN | FOLL_GET))) return -EINVAL;