mm/kmemleak: reset tag when compare object pointer

mm/kmemleak: reset tag when compare object pointer

BugLink: https://bugs.launchpad.net/bugs/1969110
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>
(cherry picked from commit 7d3bd683e0849f0ec52fefa8070734dedc3b33a1)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>