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Mon, 7 Apr 2025 03:03:34 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (unknown [10.72.112.15]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 3ECF51801752; Mon, 7 Apr 2025 03:03:28 +0000 (UTC) From: Baoquan He To: linux-mm@kvack.org Cc: akpm@linux-foundation.org, osalvador@suse.de, david@redhat.com, mingo@kernel.org, yanjun.zhu@linux.dev, linux-kernel@vger.kernel.org, Baoquan He Subject: [PATCH v3 1/3] mm/gup: fix wrongly calculated returned value in fault_in_safe_writeable() Date: Mon, 7 Apr 2025 11:03:04 +0800 Message-ID: <20250407030306.411977-2-bhe@redhat.com> In-Reply-To: <20250407030306.411977-1-bhe@redhat.com> References: <20250407030306.411977-1-bhe@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 459EA18000C X-Stat-Signature: 6ruqqx3am1zysiq4x1a8ip1kom6kbq6c X-Rspam-User: X-HE-Tag: 1743995020-122918 X-HE-Meta: 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 abSmkh+T TiufSfqRdl+CC3HRzaX0NUlkXmu9iaYi+AeKd7FTS6T/0ItX0mrjk5TSQoJofMvf6O6CiRgjqRzAk9ed4Enw+qRV+IWQbOblXZ0KdkrsYMW+hLz6zY9GIuY7TPyJi660DvH9TmQkNx7gieVIjUYQXAJKewn2Wtuy7AgBUpGIDgfB6y18X6PJ2JfKQSyJTPHEkyNc1AyMuTTqXD29Aeke6UHEdbyvJ8LUkMTd6mJWJHziDsYe1A4ZA3nei1SV5hYn4yaGru74rYRy1vvogcK+oniZxxZtR+AcjF6mflX/CNe2c+wTSdwzBEjUNzVChxcdTF7iUcXJ8n0/mf3Vl9U9XtHL8MSNkOwr3kA2IiHC/lyg/mJ0D9bkQ/41gPot2jtCfdwL/ 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: Not like fault_in_readable() or fault_in_writeable(), in fault_in_safe_writeable() local variable 'start' is increased page by page to loop till the whole address range is handled. However, it mistakenly calcalates the size of handled range with 'uaddr - start'. Here fix the code bug in fault_in_safe_writeable(), and also adjusting the codes in fault_in_readable() and fault_in_writeable() to use local variable 'start' to loop so that codes in these three functions are consistent. Signed-off-by: Baoquan He --- mm/gup.c | 40 ++++++++++++++++++++-------------------- 1 file changed, 20 insertions(+), 20 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 92351e2fa876..67a7de9e4f80 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2114,7 +2114,7 @@ static long __get_user_pages_locked(struct mm_struct *mm, unsigned long start, */ size_t fault_in_writeable(char __user *uaddr, size_t size) { - char __user *start = uaddr, *end; + unsigned long start = (unsigned long)uaddr, end; if (unlikely(size == 0)) return 0; @@ -2122,20 +2122,20 @@ size_t fault_in_writeable(char __user *uaddr, size_t size) return size; if (!PAGE_ALIGNED(uaddr)) { unsafe_put_user(0, uaddr, out); - uaddr = (char __user *)PAGE_ALIGN((unsigned long)uaddr); + start = PAGE_ALIGN((unsigned long)uaddr); } - end = (char __user *)PAGE_ALIGN((unsigned long)start + size); + end = PAGE_ALIGN(start + size); if (unlikely(end < start)) - end = NULL; - while (uaddr != end) { - unsafe_put_user(0, uaddr, out); - uaddr += PAGE_SIZE; + end = 0; + while (start != end) { + unsafe_put_user(0, (char __user *)start, out); + start += PAGE_SIZE; } out: user_write_access_end(); - if (size > uaddr - start) - return size - (uaddr - start); + if (size > start - (unsigned long)uaddr) + return size - (start - (unsigned long)uaddr); return 0; } EXPORT_SYMBOL(fault_in_writeable); @@ -2207,8 +2207,8 @@ size_t fault_in_safe_writeable(const char __user *uaddr, size_t size) } while (start != end); mmap_read_unlock(mm); - if (size > (unsigned long)uaddr - start) - return size - ((unsigned long)uaddr - start); + if (size > start - (unsigned long)uaddr) + return size - (start - (unsigned long)uaddr); return 0; } EXPORT_SYMBOL(fault_in_safe_writeable); @@ -2223,7 +2223,7 @@ EXPORT_SYMBOL(fault_in_safe_writeable); */ size_t fault_in_readable(const char __user *uaddr, size_t size) { - const char __user *start = uaddr, *end; + unsigned long start = (unsigned long)uaddr, end; volatile char c; if (unlikely(size == 0)) @@ -2232,21 +2232,21 @@ size_t fault_in_readable(const char __user *uaddr, size_t size) return size; if (!PAGE_ALIGNED(uaddr)) { unsafe_get_user(c, uaddr, out); - uaddr = (const char __user *)PAGE_ALIGN((unsigned long)uaddr); + start = PAGE_ALIGN((unsigned long)uaddr); } - end = (const char __user *)PAGE_ALIGN((unsigned long)start + size); + end = PAGE_ALIGN(start + size); if (unlikely(end < start)) - end = NULL; - while (uaddr != end) { - unsafe_get_user(c, uaddr, out); - uaddr += PAGE_SIZE; + end = 0; + while (start != end) { + unsafe_get_user(c, (const char __user *)start, out); + start += PAGE_SIZE; } out: user_read_access_end(); (void)c; - if (size > uaddr - start) - return size - (uaddr - start); + if (size > start - (unsigned long)uaddr) + return size - (start - (unsigned long)uaddr); return 0; } EXPORT_SYMBOL(fault_in_readable); From patchwork Mon Apr 7 03:03:05 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baoquan He X-Patchwork-Id: 14039661 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA3EEC36002 for ; 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Sun, 06 Apr 2025 23:03:43 -0400 X-MC-Unique: oMN4FsPAPlG8CptC09g51A-1 X-Mimecast-MFC-AGG-ID: oMN4FsPAPlG8CptC09g51A_1743995022 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C9B701800257; Mon, 7 Apr 2025 03:03:41 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (unknown [10.72.112.15]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id D41EF1801752; Mon, 7 Apr 2025 03:03:35 +0000 (UTC) From: Baoquan He To: linux-mm@kvack.org Cc: akpm@linux-foundation.org, osalvador@suse.de, david@redhat.com, mingo@kernel.org, yanjun.zhu@linux.dev, linux-kernel@vger.kernel.org, Baoquan He Subject: [PATCH v3 2/3] mm/gup: remove unneeded checking in follow_page_pte() Date: Mon, 7 Apr 2025 11:03:05 +0800 Message-ID: <20250407030306.411977-3-bhe@redhat.com> In-Reply-To: <20250407030306.411977-1-bhe@redhat.com> References: <20250407030306.411977-1-bhe@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Rspamd-Queue-Id: 51CDFC0003 X-Stat-Signature: dx9wfrsh5tq5eotiyut35tair1kqgmnz X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1743995027-508189 X-HE-Meta: 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 31S0nCNv Lu4VAno02tilLnWIx9rnjIvTOUnB+amV1P5DdcWN+dIK2TNSXsBrjvsTwCPE2AX9d7xNikzTQ7p990zuVsTijzG8Bdj7Uf4GSuntaGuvA6BhcuXo= 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: 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 set. However, it's not supported both GUP_GET and GUP_PIN are set. Even though this check need be done, it should be done earlier, but not doing it till entering into follow_page_pte() and failed. Furthermore, this checking has been done in is_valid_gup_args() and all external users of __get_user_pages() will call is_valid_gup_args() to catch the illegal setting. We don't need to worry about internal users of __get_user_pages() because the gup_flags are set by MM code correctly. Here remove the checking in follow_page_pte(), and add VM_WARN_ON_ONCE() to catch the possible exceptional setting just in case. And also change the VM_BUG_ON to VM_WARN_ON_ONCE() for checking (!!pages != !!(gup_flags & (FOLL_GET | FOLL_PIN))) because the checking has been done in is_valid_gup_args() for external users of __get_user_pages(). Signed-off-by: Baoquan He Reviewed-by: Oscar Salvador Acked-by: David Hildenbrand --- mm/gup.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 67a7de9e4f80..5b3ac5a867a3 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -844,11 +844,6 @@ 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); @@ -1432,7 +1427,11 @@ 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. */ + VM_WARN_ON_ONCE((gup_flags & (FOLL_PIN | FOLL_GET)) == + (FOLL_PIN | FOLL_GET)); 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Mon, 7 Apr 2025 03:03:48 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (unknown [10.72.112.15]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id CB5CC1801A6D; Mon, 7 Apr 2025 03:03:42 +0000 (UTC) From: Baoquan He To: linux-mm@kvack.org Cc: akpm@linux-foundation.org, osalvador@suse.de, david@redhat.com, mingo@kernel.org, yanjun.zhu@linux.dev, linux-kernel@vger.kernel.org, Baoquan He Subject: [PATCH v3 3/3] mm/gup: remove gup_fast_pgd_leaf() and clean up the relevant codes Date: Mon, 7 Apr 2025 11:03:06 +0800 Message-ID: <20250407030306.411977-4-bhe@redhat.com> In-Reply-To: <20250407030306.411977-1-bhe@redhat.com> References: <20250407030306.411977-1-bhe@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 79153C0007 X-Stat-Signature: ntqcmkeibbfz83c4hhdx7iyiy1eg3pmd X-Rspam-User: X-HE-Tag: 1743995033-740544 X-HE-Meta: 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 wdQeVW6s lB73NiMq9w6qzBrM5RtzGL3MUd+FQWsE6Jq6tvFvhohye8SQKSNTBHELa/AvAKpBK4d+LQQAz4MXR0oZcEx6GKxpq8/I8xuseu2PJXRs278YytdeLXwpB/ydxAAqG1pgI8vN8kXhPMfMLe1HzKjIDh3Im/GO8I6dEFxttwCZg7Bc2VtpiA4gyrTMPDIKTeCRr74HCaPBLcudfU30RtYcRTnjEiMsnNp09wBA7N2Mdn2h2cMxyddZ7n/cg8Cfu7eJdHTAt0gpr1etQeCeLsy4svps9hIOizvMJsZz0Lpk0Nfxo6lUm72J/VrDe+xc+cFmpdVGE3+tyxuqMNKbwc5z5m0BDAvMlSj0JZYzAozmbGUn+lTWvtvPk+kR4LcWsN0XoB75h 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: In the current kernel, only pud huge page is supported in some architectures. P4d and pgd huge pages haven't been supported yet. And in mm/gup.c, there's no pgd huge page handling in the follow_page_mask() code path. Hence it doesn't make sense to only have gup_fast_pgd_leaf() in gup_fast code path. Here remove gup_fast_pgd_leaf() and clean up the relevant codes. Signed-off-by: Baoquan He Reviewed-by: Oscar Salvador Acked-by: David Hildenbrand --- mm/gup.c | 49 +++---------------------------------------------- 1 file changed, 3 insertions(+), 46 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 5b3ac5a867a3..c9237db3cdb3 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -3172,46 +3172,6 @@ static int gup_fast_pud_leaf(pud_t orig, pud_t *pudp, unsigned long addr, return 1; } -static int gup_fast_pgd_leaf(pgd_t orig, pgd_t *pgdp, unsigned long addr, - unsigned long end, unsigned int flags, struct page **pages, - int *nr) -{ - int refs; - struct page *page; - struct folio *folio; - - if (!pgd_access_permitted(orig, flags & FOLL_WRITE)) - return 0; - - BUILD_BUG_ON(pgd_devmap(orig)); - - page = pgd_page(orig); - refs = record_subpages(page, PGDIR_SIZE, addr, end, pages + *nr); - - folio = try_grab_folio_fast(page, refs, flags); - if (!folio) - return 0; - - if (unlikely(pgd_val(orig) != pgd_val(*pgdp))) { - gup_put_folio(folio, refs, flags); - return 0; - } - - if (!pgd_write(orig) && gup_must_unshare(NULL, flags, &folio->page)) { - gup_put_folio(folio, refs, flags); - return 0; - } - - if (!gup_fast_folio_allowed(folio, flags)) { - gup_put_folio(folio, refs, flags); - return 0; - } - - *nr += refs; - folio_set_referenced(folio); - return 1; -} - static int gup_fast_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr, unsigned long end, unsigned int flags, struct page **pages, int *nr) @@ -3306,12 +3266,9 @@ static void gup_fast_pgd_range(unsigned long addr, unsigned long end, next = pgd_addr_end(addr, end); if (pgd_none(pgd)) return; - if (unlikely(pgd_leaf(pgd))) { - if (!gup_fast_pgd_leaf(pgd, pgdp, addr, next, flags, - pages, nr)) - return; - } else if (!gup_fast_p4d_range(pgdp, pgd, addr, next, flags, - pages, nr)) + BUILD_BUG_ON(pgd_leaf(pgd)); + if (!gup_fast_p4d_range(pgdp, pgd, addr, next, flags, + pages, nr)) return; } while (pgdp++, addr = next, addr != end); }