linux-kernel - [syzbot] KMSAN: uninit-value in mpol_rebind

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Message-ID: <000000000000bf60b605d7ba64b2@google.com>
Date:   Fri, 11 Feb 2022 01:07:17 -0800
From:   syzbot <syzbot+ad1b8c404f0959c4bfcc@...kaller.appspotmail.com>
To:     akpm@...ux-foundation.org, glider@...gle.com,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        syzkaller-bugs@...glegroups.com
Subject: [syzbot] KMSAN: uninit-value in mpol_rebind_mm (2)

Hello,

syzbot found the following issue on:

HEAD commit:    85cfd6e539bd kmsan: core: delete kmsan_gup_pgd_range()
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=17a505dc700000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b9807dd5b044fd7a
dashboard link: https://syzkaller.appspot.com/bug?extid=ad1b8c404f0959c4bfcc
compiler:       clang version 14.0.0 (/usr/local/google/src/llvm-git-monorepo 2b554920f11c8b763cd9ed9003f4e19b919b8e1f), GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10bcfdb2700000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=124ca21c700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ad1b8c404f0959c4bfcc@...kaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in mpol_rebind_policy mm/mempolicy.c:352 [inline]
BUG: KMSAN: uninit-value in mpol_rebind_mm+0x35b/0x460 mm/mempolicy.c:383
 mpol_rebind_policy mm/mempolicy.c:352 [inline]
 mpol_rebind_mm+0x35b/0x460 mm/mempolicy.c:383
 cpuset_attach+0xe28/0x15e0 kernel/cgroup/cpuset.c:2291
 cgroup_migrate_execute+0x1023/0x1d20 kernel/cgroup/cgroup.c:2515
 cgroup_migrate kernel/cgroup/cgroup.c:2771 [inline]
 cgroup_attach_task+0x540/0x8b0 kernel/cgroup/cgroup.c:2804
 __cgroup1_procs_write+0x5cc/0x7a0 kernel/cgroup/cgroup-v1.c:520
 cgroup1_procs_write+0x97/0xb0 kernel/cgroup/cgroup-v1.c:533
 cgroup_file_write+0x4c2/0x9e0 kernel/cgroup/cgroup.c:3852
 kernfs_fop_write_iter+0x66a/0x9f0 fs/kernfs/file.c:296
 call_write_iter include/linux/fs.h:2162 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0x1318/0x2030 fs/read_write.c:590
 ksys_write+0x28b/0x510 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0xdb/0x120 fs/read_write.c:652
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Uninit was stored to memory at:
 __mpol_dup+0x107/0x480 mm/mempolicy.c:2326
 mpol_dup include/linux/mempolicy.h:87 [inline]
 vma_replace_policy mm/mempolicy.c:762 [inline]
 mbind_range+0x13ee/0x1e40 mm/mempolicy.c:833
 do_mbind+0x13d2/0x1b30 mm/mempolicy.c:1323
 kernel_mbind mm/mempolicy.c:1477 [inline]
 __do_sys_mbind mm/mempolicy.c:1484 [inline]
 __se_sys_mbind+0x51c/0xc80 mm/mempolicy.c:1480
 __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1480
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Uninit was created at:
 slab_post_alloc_hook mm/slab.h:524 [inline]
 slab_alloc_node mm/slub.c:3251 [inline]
 slab_alloc mm/slub.c:3259 [inline]
 kmem_cache_alloc+0x902/0x11c0 mm/slub.c:3264
 mpol_new mm/mempolicy.c:293 [inline]
 do_mbind+0x8f5/0x1b30 mm/mempolicy.c:1279
 kernel_mbind mm/mempolicy.c:1477 [inline]
 __do_sys_mbind mm/mempolicy.c:1484 [inline]
 __se_sys_mbind+0x51c/0xc80 mm/mempolicy.c:1480
 __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1480
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x44/0xae

CPU: 0 PID: 3474 Comm: syz-executor399 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================


---
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