[RFC PATCH RESEND 07/28] kernel/fork: mark VMAs as locked before copying pages during fork
From: Suren Baghdasaryan <surenb@google.com>
Date: 2022-09-01 17:36:48
Also in:
linux-arm-kernel, linux-mm, lkml
Subsystem:
exec & binfmt api, elf, memory management - core, scheduler, the rest · Maintainers:
Kees Cook, Andrew Morton, David Hildenbrand, Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
Protect VMAs from concurrent page fault handler while performing copy_page_range for VMAs having VM_WIPEONFORK flag set. Signed-off-by: Suren Baghdasaryan <surenb@google.com> --- kernel/fork.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index bfab31ecd11e..1872ad549fed 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c@@ -709,8 +709,10 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, rb_parent = &tmp->vm_rb; mm->map_count++; - if (!(tmp->vm_flags & VM_WIPEONFORK)) + if (!(tmp->vm_flags & VM_WIPEONFORK)) { + vma_mark_locked(mpnt); retval = copy_page_range(tmp, mpnt); + } if (tmp->vm_ops && tmp->vm_ops->open) tmp->vm_ops->open(tmp);
--
2.37.2.789.g6183377224-goog