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Date:   Tue, 31 Aug 2021 03:36:23 -0700
Message-ID: <0000000000006dd93205cad885e5@google.com>
Subject: [syzbot] WARNING in ovl_create_real
From:   syzbot <syzbot+75eab84fd0af9e8bf66b@syzkaller.appspotmail.com>
To:     linux-kernel@vger.kernel.org, linux-unionfs@vger.kernel.org,
        miklos@szeredi.hu, syzkaller-bugs@googlegroups.com
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Precedence: bulk

Hello,

syzbot found the following issue on:

HEAD commit:    4ccc9e2db7ac Add linux-next specific files for 20210729
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13891f5c300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=75a5bed89b5c0fd2
dashboard link: https://syzkaller.appspot.com/bug?extid=75eab84fd0af9e8bf66b
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1085e076300000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14247a56300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+75eab84fd0af9e8bf66b@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 6576 at fs/overlayfs/dir.c:212 ovl_create_real+0x272/0x520 fs/overlayfs/dir.c:212
Modules linked in:
CPU: 1 PID: 6576 Comm: syz-executor088 Not tainted 5.14.0-rc3-next-20210729-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:ovl_create_real+0x272/0x520 fs/overlayfs/dir.c:212
Code: 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 80 02 00 00 49 83 7c 24 68 00 0f 85 7a fe ff ff e8 de b6 c3 fe <0f> 0b 4c 89 e5 49 c7 c4 fb ff ff ff e9 57 fe ff ff 66 81 eb 00 10
RSP: 0018:ffffc90002bef958 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000004000 RCX: 0000000000000000
RDX: ffff88807b10b900 RSI: ffffffff82b20102 RDI: ffff88806f971208
RBP: ffff88806f9711a0 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff82b2018b R11: 0000000000000000 R12: ffff88806f9711a0
R13: 0000000000004000 R14: ffff8880715c8a20 R15: ffff8880715c8b00
FS:  00007fe7eef6d700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f49bbacf000 CR3: 000000001eea6000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ovl_workdir_create+0x3a9/0x5b0 fs/overlayfs/super.c:790
 ovl_make_workdir fs/overlayfs/super.c:1364 [inline]
 ovl_get_workdir fs/overlayfs/super.c:1511 [inline]
 ovl_fill_super+0x199a/0x5fb0 fs/overlayfs/super.c:2067
 mount_nodev+0x60/0x110 fs/super.c:1414
 legacy_get_tree+0x105/0x220 fs/fs_context.c:610
 vfs_get_tree+0x89/0x2f0 fs/super.c:1498
 do_new_mount fs/namespace.c:2978 [inline]
 path_mount+0x132a/0x1fa0 fs/namespace.c:3308
 do_mount fs/namespace.c:3321 [inline]
 __do_sys_mount fs/namespace.c:3529 [inline]
 __se_sys_mount fs/namespace.c:3506 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3506
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4458d9
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:00007fe7eef6d2f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000004ca400 RCX: 00000000004458d9
RDX: 00000000200000c0 RSI: 0000000020000000 RDI: 000000000040000d
RBP: 000000000049a074 R08: 0000000020000100 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e
R13: 0079616c7265766f R14: 003270756f726763 R15: 00000000004ca408


---
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