[PATCH v16 04/16] mm: untag user pointers in do_pages_move

Andrey Konovalov andreyknvl at google.com
Mon Jun 3 16:55:06 UTC 2019

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

do_pages_move() is used in the implementation of the move_pages syscall.

Untag user pointers in this function.

Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl at google.com>
 mm/migrate.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/migrate.c b/mm/migrate.c
index f2ecc2855a12..3930bb6fa656 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1617,6 +1617,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
 		if (get_user(node, nodes + i))
 			goto out_flush;
 		addr = (unsigned long)p;
+		addr = untagged_addr(addr);
 		err = -ENODEV;
 		if (node < 0 || node >= MAX_NUMNODES)

More information about the amd-gfx mailing list