Message-ID: <YymkSpsiv/JZ73s1@elver.google.com>
Date:   Tue, 20 Sep 2022 13:30:18 +0200
From:   Marco Elver <elver@...gle.com>
To:     syzbot <syzbot+870ae3a4c7a251c996bd@...kaller.appspotmail.com>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        syzkaller-bugs@...glegroups.com, viro@...iv.linux.org.uk,
        Konstantin Komarov <almaz.alexandrovich@...agon-software.com>,
        ntfs3@...ts.linux.dev
Subject: Re: [syzbot] KASAN: stack-out-of-bounds Read in iput

+Cc ntfs3 maintainers

On Tue, Sep 20, 2022 at 03:35AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    521a547ced64 Linux 6.0-rc6
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=12c41580880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c221af36f6d1d811
> dashboard link: https://syzkaller.appspot.com/bug?extid=870ae3a4c7a251c996bd
> compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=110f0654880000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1625e737080000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/7daadf43221d/disk-521a547c.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/7e776edd0f78/vmlinux-521a547c.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+870ae3a4c7a251c996bd@...kaller.appspotmail.com
> 
> ntfs3: loop2: RAW NTFS volume: Filesystem size 0.00 Gb > volume size 0.00 Gb. Mount in read-only
> ==================================================================
> BUG: KASAN: stack-out-of-bounds in native_save_fl arch/x86/include/asm/irqflags.h:35 [inline]
> BUG: KASAN: stack-out-of-bounds in arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
> BUG: KASAN: stack-out-of-bounds in arch_irqs_disabled arch/x86/include/asm/irqflags.h:130 [inline]
> BUG: KASAN: stack-out-of-bounds in lock_acquire+0x1c3/0x3c0 kernel/locking/lockdep.c:5669
> Read of size 8 at addr ffffc9000b7df95f by task syz-executor383/13922
> 
> CPU: 0 PID: 13922 Comm: syz-executor383 Not tainted 6.0.0-rc6-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
> 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
>  native_save_fl arch/x86/include/asm/irqflags.h:35 [inline]
>  arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
>  arch_irqs_disabled arch/x86/include/asm/irqflags.h:130 [inline]
>  lock_acquire+0x1c3/0x3c0 kernel/locking/lockdep.c:5669
>  __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
>  _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
>  spin_lock include/linux/spinlock.h:349 [inline]
>  iput_final fs/inode.c:1737 [inline]
>  iput+0x3ee/0x760 fs/inode.c:1774
>  ntfs_fill_super+0x2352/0x42a0 fs/ntfs3/super.c:1278
>  get_tree_bdev+0x400/0x620 fs/super.c:1323
>  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
> RIP: 0033:0x7f203d446d7a
> Code: 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 d8 00 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 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:00007f203d3f1078 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
> RAX: ffffffffffffffda RBX: 00007f203d3f10d0 RCX: 00007f203d446d7a
> RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f203d3f1090
> RBP: 000000000000000e R08: 00007f203d3f10d0 R09: 00007f203d3f16b8
> R10: 0000000000000000 R11: 0000000000000286 R12: 00007f203d3f1090
> R13: 0000000020000350 R14: 0000000000000003 R15: 0000000000000004
>  </TASK>
> 
> The buggy address belongs to stack of task syz-executor383/13922
>  and is located at offset 31 in frame:
>  lock_acquire+0x0/0x3c0 kernel/locking/lockdep.c:5621
> 
> This frame has 3 objects:
>  [32, 40) 'flags.i.i.i87'
>  [64, 72) 'flags.i.i.i'
>  [96, 136) 'hlock'
> 
> The buggy address belongs to the virtual mapping at
>  [ffffc9000b7d8000, ffffc9000b7e1000) created by:
>  dup_task_struct+0x8b/0x490 kernel/fork.c:977
> 
> The buggy address belongs to the physical page:
> page:ffffea0001bcb8c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6f2e3
> flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
> raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
> raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_ZERO), pid 3629, tgid 3629 (syz-executor383), ts 473162860658, free_ts 11190855215
>  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:5515
>  vm_area_alloc_pages mm/vmalloc.c:2958 [inline]
>  __vmalloc_area_node mm/vmalloc.c:3026 [inline]
>  __vmalloc_node_range+0x8f4/0x1290 mm/vmalloc.c:3196
>  alloc_thread_stack_node+0x307/0x500 kernel/fork.c:312
>  dup_task_struct+0x8b/0x490 kernel/fork.c:977
>  copy_process+0x65b/0x3fd0 kernel/fork.c:2088
>  kernel_clone+0x21f/0x790 kernel/fork.c:2674
>  __do_sys_clone kernel/fork.c:2808 [inline]
>  __se_sys_clone kernel/fork.c:2792 [inline]
>  __x64_sys_clone+0x228/0x290 kernel/fork.c:2792
>  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
> 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_contig_range+0xa3/0x160 mm/page_alloc.c:9408
>  destroy_args+0xfe/0x91d mm/debug_vm_pgtable.c:1031
>  debug_vm_pgtable+0x43e/0x497 mm/debug_vm_pgtable.c:1354
>  do_one_initcall+0x1b9/0x3e0 init/main.c:1296
>  do_initcall_level+0x168/0x218 init/main.c:1369
>  do_initcalls+0x4b/0x8c init/main.c:1385
>  kernel_init_freeable+0x3f1/0x57b init/main.c:1623
>  kernel_init+0x19/0x2b0 init/main.c:1512
>  ret_from_fork+0x1f/0x30
> 
> Memory state around the buggy address:
>  ffffc9000b7df800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>  ffffc9000b7df880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >ffffc9000b7df900: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f2 f2 f2
>                                                     ^
>  ffffc9000b7df980: 00 f2 f2 f2 00 00 00 00 00 f3 f3 f3 f3 f3 f3 f3
>  ffffc9000b7dfa00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ==================================================================
> 
> 
> ---
> 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.
> syzbot can test patches for this issue, for details see:
> https://goo.gl/tpsmEJ#testing-patches

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