syzbot

==================================================================
BUG: KMSAN: uninit-value in __bitmap_equal+0x151/0x2e0 lib/bitmap.c:55
CPU: 0 PID: 14025 Comm: syz-executor5 Not tainted 4.19.0-rc8+ #70
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x306/0x460 lib/dump_stack.c:113
 kmsan_report+0x1a2/0x2e0 mm/kmsan/kmsan.c:917
 __msan_warning+0x7c/0xe0 mm/kmsan/kmsan_instr.c:500
 __bitmap_equal+0x151/0x2e0 lib/bitmap.c:55
 bitmap_equal include/linux/bitmap.h:328 [inline]
 __nodes_equal include/linux/nodemask.h:206 [inline]
 mpol_rebind_policy mm/mempolicy.c:354 [inline]
 mpol_rebind_task+0x11d/0x220 mm/mempolicy.c:369
 cpuset_change_task_nodemask kernel/cgroup/cpuset.c:1068 [inline]
 cpuset_attach+0x61d/0x1280 kernel/cgroup/cpuset.c:1548
 cgroup_migrate_execute+0xbb3/0x1b10 kernel/cgroup/cgroup.c:2343
 cgroup_migrate kernel/cgroup/cgroup.c:2602 [inline]
 cgroup_attach_task+0x671/0x1270 kernel/cgroup/cgroup.c:2639
 __cgroup1_procs_write+0x618/0x730 kernel/cgroup/cgroup-v1.c:550
 cgroup1_procs_write+0x9b/0xb0 kernel/cgroup/cgroup-v1.c:563
 cgroup_file_write+0x44a/0x8e0 kernel/cgroup/cgroup.c:3457
 kernfs_fop_write+0x607/0x8a0 fs/kernfs/file.c:316
 __vfs_write+0x1f4/0xb70 fs/read_write.c:485
 vfs_write+0x495/0x8e0 fs/read_write.c:549
 ksys_write fs/read_write.c:598 [inline]
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write+0x183/0x370 fs/read_write.c:607
 __x64_sys_write+0x4a/0x70 fs/read_write.c:607
 do_syscall_64+0xbe/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457569
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb063e82c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569
RDX: 0000000000000012 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb063e836d4
R13: 00000000004c5571 R14: 00000000004d8eb0 R15: 00000000ffffffff

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:255 [inline]
 kmsan_internal_poison_shadow+0xc8/0x1d0 mm/kmsan/kmsan.c:180
 kmsan_kmalloc+0xa4/0x120 mm/kmsan/kmsan_hooks.c:104
 kmem_cache_alloc+0x694/0xd50 mm/slub.c:2746
 mpol_new+0x426/0x6f0 mm/mempolicy.c:276
 do_set_mempolicy+0x12a/0x7f0 mm/mempolicy.c:748
 kernel_set_mempolicy mm/mempolicy.c:1360 [inline]
 __do_sys_set_mempolicy mm/mempolicy.c:1366 [inline]
 __se_sys_set_mempolicy+0x21b/0x2b0 mm/mempolicy.c:1363
 __x64_sys_set_mempolicy+0x4a/0x70 mm/mempolicy.c:1363
 do_syscall_64+0xbe/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
==================================================================