Date:   Thu, 6 Oct 2022 22:44:04 +0900
From:   Ryusuke Konishi <konishi.ryusuke@...il.com>
To:     syzbot <syzbot+983470d8253700fc9461@...kaller.appspotmail.com>
Cc:     linux-kernel@...r.kernel.org, linux-nilfs@...r.kernel.org,
        syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] KASAN: use-after-free Read in nilfs_permission

On Thu, Oct 6, 2022 at 8:25 PM syzbot wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    2bca25eaeba6 Merge tag 'spi-v6.1' of git://git.kernel.org/..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=154675f4880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=9df203be43a870b5
> dashboard link: https://syzkaller.appspot.com/bug?extid=983470d8253700fc9461
> compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/9885e6765755/disk-2bca25ea.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/6e78c91286aa/vmlinux-2bca25ea.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+983470d8253700fc9461@...kaller.appspotmail.com
>
> ==================================================================
> BUG: KASAN: use-after-free in nilfs_permission+0x65/0xb0 fs/nilfs2/inode.c:980
> Read of size 8 at addr ffff888079155000 by task syz-executor.2/8538
>
> CPU: 0 PID: 8538 Comm: syz-executor.2 Not tainted 6.0.0-syzkaller-03015-g2bca25eaeba6 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
>  print_address_description+0x65/0x4b0 mm/kasan/report.c:317
>  print_report+0x108/0x1f0 mm/kasan/report.c:433
>  kasan_report+0xc3/0xf0 mm/kasan/report.c:495
>  nilfs_permission+0x65/0xb0 fs/nilfs2/inode.c:980
>  do_inode_permission fs/namei.c:458 [inline]
>  inode_permission+0x22c/0x450 fs/namei.c:525
>  may_o_create fs/namei.c:3242 [inline]
>  lookup_open fs/namei.c:3376 [inline]
>  open_last_lookups fs/namei.c:3481 [inline]
>  path_openat+0xcea/0x2df0 fs/namei.c:3688
>  do_filp_open+0x264/0x4f0 fs/namei.c:3718
>  do_sys_openat2+0x124/0x4e0 fs/open.c:1313
>  do_sys_open fs/open.c:1329 [inline]
>  __do_sys_creat fs/open.c:1405 [inline]
>  __se_sys_creat fs/open.c:1399 [inline]
>  __x64_sys_creat+0x11f/0x160 fs/open.c:1399
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7fd71d88a5a9
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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:00007fd71e916168 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
> RAX: ffffffffffffffda RBX: 00007fd71d9ac120 RCX: 00007fd71d88a5a9
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000180
> RBP: 00007fd71d8e5580 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007ffc40edd1af R14: 00007fd71e916300 R15: 0000000000022000
>  </TASK>
>
> Allocated by task 8531:
>  kasan_save_stack mm/kasan/common.c:38 [inline]
>  kasan_set_track mm/kasan/common.c:45 [inline]
>  set_alloc_info mm/kasan/common.c:437 [inline]
>  ____kasan_kmalloc+0xcd/0x100 mm/kasan/common.c:516
>  kasan_kmalloc include/linux/kasan.h:234 [inline]
>  kmem_cache_alloc_trace+0x97/0x310 mm/slub.c:3289
>  kmalloc include/linux/slab.h:600 [inline]
>  kzalloc include/linux/slab.h:733 [inline]
>  nilfs_find_or_create_root+0x142/0x4f0 fs/nilfs2/the_nilfs.c:747
>  nilfs_attach_checkpoint+0xcd/0x4a0 fs/nilfs2/super.c:519
>  nilfs_fill_super+0x2e8/0x5d0 fs/nilfs2/super.c:1064
>  nilfs_mount+0x613/0x9b0 fs/nilfs2/super.c:1317
>  legacy_get_tree+0xea/0x180 fs/fs_context.c:610
>  vfs_get_tree+0x88/0x270 fs/super.c:1530
>  do_new_mount+0x289/0xad0 fs/namespace.c:3040
>  do_mount fs/namespace.c:3383 [inline]
>  __do_sys_mount fs/namespace.c:3591 [inline]
>  __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> Freed by task 8531:
>  kasan_save_stack mm/kasan/common.c:38 [inline]
>  kasan_set_track+0x3d/0x60 mm/kasan/common.c:45
>  kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:370
>  ____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:367
>  kasan_slab_free include/linux/kasan.h:200 [inline]
>  slab_free_hook mm/slub.c:1759 [inline]
>  slab_free_freelist_hook+0x12e/0x1a0 mm/slub.c:1785
>  slab_free mm/slub.c:3539 [inline]
>  kfree+0xda/0x210 mm/slub.c:4567
>  nilfs_evict_inode+0x253/0x3d0 fs/nilfs2/inode.c:924
>  evict+0x2a4/0x620 fs/inode.c:665
>  nilfs_new_inode+0x6b8/0x8a0
>  nilfs_create+0xdc/0x2d0 fs/nilfs2/namei.c:85
>  lookup_open fs/namei.c:3413 [inline]
>  open_last_lookups fs/namei.c:3481 [inline]
>  path_openat+0x12d0/0x2df0 fs/namei.c:3688
>  do_filp_open+0x264/0x4f0 fs/namei.c:3718
>  do_sys_openat2+0x124/0x4e0 fs/open.c:1313
>  do_sys_open fs/open.c:1329 [inline]
>  __do_sys_creat fs/open.c:1405 [inline]
>  __se_sys_creat fs/open.c:1399 [inline]
>  __x64_sys_creat+0x11f/0x160 fs/open.c:1399
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> Last potentially related work creation:
>  kasan_save_stack+0x2b/0x50 mm/kasan/common.c:38
>  __kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:348
>  call_rcu+0x163/0x970 kernel/rcu/tree.c:2796
>  free_fib_info net/ipv4/fib_semantics.c:256 [inline]
>  fib_info_put include/net/ip_fib.h:578 [inline]
>  fib_release_info+0x654/0x720 net/ipv4/fib_semantics.c:281
>  fib_table_flush+0xca2/0x1310 net/ipv4/fib_trie.c:2090
>  fib_flush net/ipv4/fib_frontend.c:195 [inline]
>  fib_disable_ip net/ipv4/fib_frontend.c:1420 [inline]
>  fib_netdev_event+0x3bf/0x740 net/ipv4/fib_frontend.c:1489
>  notifier_call_chain kernel/notifier.c:87 [inline]
>  raw_notifier_call_chain+0xe7/0x170 kernel/notifier.c:455
>  call_netdevice_notifiers_info net/core/dev.c:1945 [inline]
>  call_netdevice_notifiers_extack net/core/dev.c:1983 [inline]
>  call_netdevice_notifiers net/core/dev.c:1997 [inline]
>  dev_close_many+0x3fb/0x5d0 net/core/dev.c:1545
>  unregister_netdevice_many+0x521/0x1aa0 net/core/dev.c:10817
>  default_device_exit_batch+0x570/0x5e0 net/core/dev.c:11337
>  ops_exit_list net/core/net_namespace.c:167 [inline]
>  cleanup_net+0x80c/0xc50 net/core/net_namespace.c:594
>  process_one_work+0x877/0xdb0 kernel/workqueue.c:2289
>  worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
>  kthread+0x266/0x300 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
>
> The buggy address belongs to the object at ffff888079155000
>  which belongs to the cache kmalloc-256 of size 256
> The buggy address is located 0 bytes inside of
>  256-byte region [ffff888079155000, ffff888079155100)
>
> The buggy address belongs to the physical page:
> page:ffffea0001e45500 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x79154
> head:ffffea0001e45500 order:1 compound_mapcount:0 compound_pincount:0
> flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
> raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888012041b40
> raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3640, tgid 3640 (syz-executor.4), ts 195699870753, free_ts 192860739281
>  prep_new_page mm/page_alloc.c:2532 [inline]
>  get_page_from_freelist+0x742/0x7c0 mm/page_alloc.c:4283
>  __alloc_pages+0x259/0x560 mm/page_alloc.c:5549
>  alloc_slab_page+0x70/0xf0 mm/slub.c:1829
>  allocate_slab+0x5e/0x520 mm/slub.c:1974
>  new_slab mm/slub.c:2034 [inline]
>  ___slab_alloc+0x3ee/0xc40 mm/slub.c:3036
>  __slab_alloc mm/slub.c:3123 [inline]
>  slab_alloc_node mm/slub.c:3214 [inline]
>  slab_alloc mm/slub.c:3256 [inline]
>  __kmalloc+0x2bd/0x370 mm/slub.c:4425
>  kmalloc include/linux/slab.h:605 [inline]
>  kzalloc include/linux/slab.h:733 [inline]
>  fib_create_info+0xa5a/0x2410 net/ipv4/fib_semantics.c:1449
>  fib_table_insert+0x1e5/0x1f50 net/ipv4/fib_trie.c:1236
>  fib_magic+0x451/0x650 net/ipv4/fib_frontend.c:1098
>  fib_add_ifaddr+0x3ea/0x5c0 net/ipv4/fib_frontend.c:1142
>  fib_netdev_event+0x628/0x740 net/ipv4/fib_frontend.c:1480
>  notifier_call_chain kernel/notifier.c:87 [inline]
>  raw_notifier_call_chain+0xe7/0x170 kernel/notifier.c:455
>  __dev_notify_flags+0x2ef/0x5d0
>  dev_change_flags+0xe3/0x190 net/core/dev.c:8615
>  do_setlink+0xef5/0x3d40 net/core/rtnetlink.c:2788
>  __rtnl_newlink net/core/rtnetlink.c:3547 [inline]
>  rtnl_newlink+0x1748/0x1fa0 net/core/rtnetlink.c:3594
> page last free stack trace:
>  reset_page_owner include/linux/page_owner.h:24 [inline]
>  free_pages_prepare mm/page_alloc.c:1449 [inline]
>  free_pcp_prepare+0x812/0x900 mm/page_alloc.c:1499
>  free_unref_page_prepare mm/page_alloc.c:3380 [inline]
>  free_unref_page+0x7d/0x5f0 mm/page_alloc.c:3476
>  free_slab mm/slub.c:2073 [inline]
>  discard_slab mm/slub.c:2079 [inline]
>  __unfreeze_partials+0x1ab/0x200 mm/slub.c:2553
>  put_cpu_partial+0x106/0x170 mm/slub.c:2629
>  qlist_free_all+0x2b/0x70 mm/kasan/quarantine.c:187
>  kasan_quarantine_reduce+0x169/0x180 mm/kasan/quarantine.c:294
>  __kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:447
>  kasan_slab_alloc include/linux/kasan.h:224 [inline]
>  slab_post_alloc_hook mm/slab.h:727 [inline]
>  slab_alloc_node mm/slub.c:3248 [inline]
>  slab_alloc mm/slub.c:3256 [inline]
>  kmem_cache_alloc_trace+0x1de/0x310 mm/slub.c:3287
>  kmalloc include/linux/slab.h:600 [inline]
>  kzalloc include/linux/slab.h:733 [inline]
>  kobject_uevent_env+0x33a/0x8e0 lib/kobject_uevent.c:524
>  __kobject_del+0xcd/0x300 lib/kobject.c:585
>  kobject_cleanup+0x25d/0x470 lib/kobject.c:664
>  net_rx_queue_update_kobjects+0x455/0x4c0 net/core/net-sysfs.c:1128
>  netif_set_real_num_rx_queues+0xf9/0x1d0 net/core/dev.c:2941
>  veth_init_queues drivers/net/veth.c:1692 [inline]
>  veth_newlink+0xa10/0xd10 drivers/net/veth.c:1807
>  rtnl_newlink_create net/core/rtnetlink.c:3364 [inline]
>  __rtnl_newlink net/core/rtnetlink.c:3581 [inline]
>  rtnl_newlink+0x147d/0x1fa0 net/core/rtnetlink.c:3594
>  rtnetlink_rcv_msg+0x772/0xe60 net/core/rtnetlink.c:6091
>
> Memory state around the buggy address:
>  ffff888079154f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>  ffff888079154f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> >ffff888079155000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                    ^
>  ffff888079155080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>  ffff888079155100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
>
>
> ---
> 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@...glegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

#syz dup: KASAN: use-after-free Read in nilfs_segctor_confirm

Looks like the same issue as above because nilfs_evict_inode() is
called as the result of a failure of nilfs_new_inode() and
nilfs_permssion() hits use-after-free read for struct nilfs_root
according to the log.

Ryusuke Konishi

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