The quilt patch titled Subject: mm/gup: fix wrongly calculated returned value in fault_in_safe_writeable() has been removed from the -mm tree. Its filename was mm-gup-fix-wrongly-calculated-returned-value-in-fault_in_safe_writeable.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------ From: Baoquan He bhe@redhat.com Subject: mm/gup: fix wrongly calculated returned value in fault_in_safe_writeable() Date: Thu, 10 Apr 2025 11:57:14 +0800

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 calculates the size of the handled range with 'uaddr - start'.

Fix it here.

Andreas said:

: In gfs2, fault_in_iov_iter_writeable() is used in : gfs2_file_direct_read() and gfs2_file_read_iter(), so this potentially : affects buffered as well as direct reads. This bug could cause those : gfs2 functions to spin in a loop.

Link: https://lkml.kernel.org/r/20250410035717.473207-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20250410035717.473207-2-bhe@redhat.com Signed-off-by: Baoquan He bhe@redhat.com Fixes: fe673d3f5bf1 ("mm: gup: make fault_in_safe_writeable() use fixup_user_fault()") Reviewed-by: Oscar Salvador osalvador@suse.de Acked-by: David Hildenbrand david@redhat.com Cc: Andreas Gruenbacher agruenba@redhat.com Cc: Yanjun.Zhu yanjun.zhu@linux.dev Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/gup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/gup.c~mm-gup-fix-wrongly-calculated-returned-value-in-fault_in_safe_writeable +++ a/mm/gup.c @@ -2207,8 +2207,8 @@ size_t fault_in_safe_writeable(const cha } 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); _

Patches currently in -mm which might be from bhe@redhat.com are

mm-gup-remove-unneeded-checking-in-follow_page_pte.patch mm-gup-remove-gup_fast_pgd_leaf-and-clean-up-the-relevant-codes.patch mm-gup-clean-up-codes-in-fault_in_xxx-functions.patch mm-gup-clean-up-codes-in-fault_in_xxx-functions-v5.patch