Re: [syzbot] [virt?] [net?] KMSAN: uninit-value in vsock_assign_transport (2)

[Michael S. Tsirkin]

On Fri, Apr 19, 2024 at 02:39:20AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    8cd26fd90c1a Merge tag 'for-6.9-rc4-tag' of git://git.kern..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=102d27cd180000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=87a805e655619c64
> dashboard link: https://syzkaller.appspot.com/bug?extid=6c21aeb59d0e82eb2782
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16e38c3b180000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10e62fed180000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/488822aee24a/disk-8cd26fd9.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/ba40e322ba00/vmlinux-8cd26fd9.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/f30af1dfbc30/bzImage-8cd26fd9.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+6c21aeb59d0e82eb2782@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> =====================================================
> BUG: KMSAN: uninit-value in vsock_assign_transport+0xb2a/0xb90 net/vmw_vsock/af_vsock.c:500
>  vsock_assign_transport+0xb2a/0xb90 net/vmw_vsock/af_vsock.c:500
>  vsock_connect+0x544/0x1560 net/vmw_vsock/af_vsock.c:1393
>  __sys_connect_file net/socket.c:2048 [inline]
>  __sys_connect+0x606/0x690 net/socket.c:2065
>  __do_sys_connect net/socket.c:2075 [inline]
>  __se_sys_connect net/socket.c:2072 [inline]
>  __x64_sys_connect+0x91/0xe0 net/socket.c:2072
>  x64_sys_call+0x3356/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:43
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> Uninit was created at:
>  __kmalloc_large_node+0x231/0x370 mm/slub.c:3921
>  __do_kmalloc_node mm/slub.c:3954 [inline]
>  __kmalloc_node+0xb07/0x1060 mm/slub.c:3973
>  kmalloc_node include/linux/slab.h:648 [inline]
>  kvmalloc_node+0xc0/0x2d0 mm/util.c:634
>  kvmalloc include/linux/slab.h:766 [inline]
>  vhost_vsock_dev_open+0x44/0x510 drivers/vhost/vsock.c:659
>  misc_open+0x66b/0x760 drivers/char/misc.c:165
>  chrdev_open+0xa5f/0xb80 fs/char_dev.c:414
>  do_dentry_open+0x11f1/0x2120 fs/open.c:955
>  vfs_open+0x7e/0xa0 fs/open.c:1089
>  do_open fs/namei.c:3642 [inline]
>  path_openat+0x4a3c/0x5b00 fs/namei.c:3799
>  do_filp_open+0x20e/0x590 fs/namei.c:3826
>  do_sys_openat2+0x1bf/0x2f0 fs/open.c:1406
>  do_sys_open fs/open.c:1421 [inline]
>  __do_sys_openat fs/open.c:1437 [inline]
>  __se_sys_openat fs/open.c:1432 [inline]
>  __x64_sys_openat+0x2a1/0x310 fs/open.c:1432
>  x64_sys_call+0x3a64/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:258
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> CPU: 1 PID: 5021 Comm: syz-executor390 Not tainted 6.9.0-rc4-syzkaller-00038-g8cd26fd90c1a #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
> =====================================================
> 
> 
> ---
> This report is generated by a bot. It may contain errors.
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> 
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> 
> If the report is already addressed, let syzbot know by replying with:
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> 
> If you want syzbot to run the reproducer, reply with:
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> 
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> 
> If the report is a duplicate of another one, reply with:
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> 
> If you want to undo deduplication, reply with:
> #syz undup


#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git bcc17a060d93b198d8a17a9b87b593f41337ee28