From: Kuan-Ying Lee Kuan-Ying.Lee@mediatek.com
commit bfc8089f00fa526dea983844c880fa8106c33ac4 upstream.
When we use HW-tag based kasan and enable vmalloc support, we hit the following bug. It is due to comparison between tagged object and non-tagged pointer.
We need to reset the kasan tag when we need to compare tagged object and non-tagged pointer.
kmemleak: [name:kmemleak&]Scan area larger than object 0xffffffe77076f440 CPU: 4 PID: 1 Comm: init Tainted: G S W 5.15.25-android13-0-g5cacf919c2bc #1 Hardware name: MT6983(ENG) (DT) Call trace: add_scan_area+0xc4/0x244 kmemleak_scan_area+0x40/0x9c layout_and_allocate+0x1e8/0x288 load_module+0x2c8/0xf00 __se_sys_finit_module+0x190/0x1d0 __arm64_sys_finit_module+0x20/0x30 invoke_syscall+0x60/0x170 el0_svc_common+0xc8/0x114 do_el0_svc+0x28/0xa0 el0_svc+0x60/0xf8 el0t_64_sync_handler+0x88/0xec el0t_64_sync+0x1b4/0x1b8 kmemleak: [name:kmemleak&]Object 0xf5ffffe77076b000 (size 32768): kmemleak: [name:kmemleak&] comm "init", pid 1, jiffies 4294894197 kmemleak: [name:kmemleak&] min_count = 0 kmemleak: [name:kmemleak&] count = 0 kmemleak: [name:kmemleak&] flags = 0x1 kmemleak: [name:kmemleak&] checksum = 0 kmemleak: [name:kmemleak&] backtrace: module_alloc+0x9c/0x120 move_module+0x34/0x19c layout_and_allocate+0x1c4/0x288 load_module+0x2c8/0xf00 __se_sys_finit_module+0x190/0x1d0 __arm64_sys_finit_module+0x20/0x30 invoke_syscall+0x60/0x170 el0_svc_common+0xc8/0x114 do_el0_svc+0x28/0xa0 el0_svc+0x60/0xf8 el0t_64_sync_handler+0x88/0xec el0t_64_sync+0x1b4/0x1b8
Link: https://lkml.kernel.org/r/20220318034051.30687-1-Kuan-Ying.Lee@mediatek.com Signed-off-by: Kuan-Ying Lee Kuan-Ying.Lee@mediatek.com Reviewed-by: Catalin Marinas catalin.marinas@arm.com Cc: Matthias Brugger matthias.bgg@gmail.com Cc: Chinwen Chang chinwen.chang@mediatek.com Cc: Nicholas Tang nicholas.tang@mediatek.com Cc: Yee Lee yee.lee@mediatek.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/kmemleak.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
--- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -796,6 +796,8 @@ static void add_scan_area(unsigned long unsigned long flags; struct kmemleak_object *object; struct kmemleak_scan_area *area = NULL; + unsigned long untagged_ptr; + unsigned long untagged_objp;
object = find_and_get_object(ptr, 1); if (!object) { @@ -804,6 +806,9 @@ static void add_scan_area(unsigned long return; }
+ untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr); + untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer); + if (scan_area_cache) area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
@@ -815,8 +820,8 @@ static void add_scan_area(unsigned long goto out_unlock; } if (size == SIZE_MAX) { - size = object->pointer + object->size - ptr; - } else if (ptr + size > object->pointer + object->size) { + size = untagged_objp + object->size - untagged_ptr; + } else if (untagged_ptr + size > untagged_objp + object->size) { kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr); dump_object_info(object); kmem_cache_free(scan_area_cache, area);