Hello, syzbot found the following issue on: HEAD commit: 4ebaab5f kmsan: drop unneeded references to kmsan_context_.. git tree: https://github.com/google/kmsan.git master console output: https://syzkaller.appspot.com/x/log.txt?x=11b6bfe5d00000 kernel config: https://syzkaller.appspot.com/x/.config?x=647ca0f5bbe7703a dashboard link: https://syzkaller.appspot.com/bug?extid=0bdecd1b2c19a1faa92d compiler: Debian clang version 11.0.1-2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11012825d00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1425f45dd00000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+0bdecd1b2c19a1faa92d@xxxxxxxxxxxxxxxxxxxxxxxxx ===================================================== BUG: KMSAN: uninit-value in __mpol_equal mm/mempolicy.c:2340 [inline] BUG: KMSAN: uninit-value in mpol_equal include/linux/mempolicy.h:108 [inline] BUG: KMSAN: uninit-value in mbind_range mm/mempolicy.c:825 [inline] BUG: KMSAN: uninit-value in do_mbind+0x2d1b/0x38c0 mm/mempolicy.c:1350 CPU: 0 PID: 8220 Comm: syz-executor545 Not tainted 5.12.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x24c/0x2e0 lib/dump_stack.c:120 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118 __msan_warning+0x5c/0xa0 mm/kmsan/kmsan_instr.c:197 __mpol_equal mm/mempolicy.c:2340 [inline] mpol_equal include/linux/mempolicy.h:108 [inline] mbind_range mm/mempolicy.c:825 [inline] do_mbind+0x2d1b/0x38c0 mm/mempolicy.c:1350 kernel_mbind mm/mempolicy.c:1478 [inline] __do_sys_mbind mm/mempolicy.c:1485 [inline] __se_sys_mbind+0x3a6/0x3c0 mm/mempolicy.c:1481 __x64_sys_mbind+0x6e/0x90 mm/mempolicy.c:1481 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4456f9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4c4152c308 EFLAGS: 00000246 ORIG_RAX: 00000000000000ed RAX: ffffffffffffffda RBX: 00000000004ca408 RCX: 00000000004456f9 RDX: 0000000000002001 RSI: 0000000000800000 RDI: 0000000020001000 RBP: 00000000004ca400 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca40c R13: 00007ffe6c9a98ff R14: 00007f4c4152c400 R15: 0000000000022000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline] kmsan_internal_poison_shadow+0x5c/0xf0 mm/kmsan/kmsan.c:104 kmsan_slab_alloc+0x8e/0xe0 mm/kmsan/kmsan_hooks.c:76 slab_alloc_node mm/slub.c:2922 [inline] slab_alloc mm/slub.c:2931 [inline] kmem_cache_alloc+0x895/0x1030 mm/slub.c:2936 mpol_new mm/mempolicy.c:302 [inline] do_mbind+0x8d5/0x38c0 mm/mempolicy.c:1306 kernel_mbind mm/mempolicy.c:1478 [inline] __do_sys_mbind mm/mempolicy.c:1485 [inline] __se_sys_mbind+0x3a6/0x3c0 mm/mempolicy.c:1481 __x64_sys_mbind+0x6e/0x90 mm/mempolicy.c:1481 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 entry_SYSCALL_64_after_hwframe+0x44/0xae ===================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
