[syzbot] memory leak in add_tree_block

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    4312098baf37 Merge tag 'spi-fix-v6.1-rc6' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1642d68d880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=522dbc1ab43c9303
dashboard link: https://syzkaller.appspot.com/bug?extid=be14ed7728594dc8bd42
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15bfbac3880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=120cff21880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/76a03ca3d4a9/disk-4312098b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5de00a38b596/vmlinux-4312098b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9499f7779db5/bzImage-4312098b.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/42f50e809c7e/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+be14ed7728594dc8bd42@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: memory leak
unreferenced object 0xffff88810f8ea480 (size 64):
  comm "syz-executor193", pid 3787, jiffies 4294971495 (age 12.820s)
  hex dump (first 32 bytes):
    03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff814ed790>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1045
    [<ffffffff820869aa>] kmalloc include/linux/slab.h:553 [inline]
    [<ffffffff820869aa>] add_tree_block+0x3a/0x210 fs/btrfs/ref-verify.c:316
    [<ffffffff82087e7c>] btrfs_build_ref_tree+0x50c/0x750 fs/btrfs/ref-verify.c:471
    [<ffffffff846b818d>] open_ctree+0x19af/0x1fcb fs/btrfs/disk-io.c:3767
    [<ffffffff846b17d6>] btrfs_fill_super fs/btrfs/super.c:1461 [inline]
    [<ffffffff846b17d6>] btrfs_mount_root.cold+0x13/0xf5 fs/btrfs/super.c:1829
    [<ffffffff81662b0b>] legacy_get_tree+0x2b/0x90 fs/fs_context.c:610
    [<ffffffff815fc948>] vfs_get_tree+0x28/0x100 fs/super.c:1531
    [<ffffffff81638b61>] fc_mount fs/namespace.c:1043 [inline]
    [<ffffffff81638b61>] vfs_kern_mount.part.0+0xd1/0x120 fs/namespace.c:1073
    [<ffffffff81638bec>] vfs_kern_mount+0x3c/0x60 fs/namespace.c:1060
    [<ffffffff81f54029>] btrfs_mount+0x199/0x590 fs/btrfs/super.c:1889
    [<ffffffff81662b0b>] legacy_get_tree+0x2b/0x90 fs/fs_context.c:610
    [<ffffffff815fc948>] vfs_get_tree+0x28/0x100 fs/super.c:1531
    [<ffffffff81640487>] do_new_mount fs/namespace.c:3040 [inline]
    [<ffffffff81640487>] path_mount+0xc37/0x10d0 fs/namespace.c:3370
    [<ffffffff8164106e>] do_mount fs/namespace.c:3383 [inline]
    [<ffffffff8164106e>] __do_sys_mount fs/namespace.c:3591 [inline]
    [<ffffffff8164106e>] __se_sys_mount fs/namespace.c:3568 [inline]
    [<ffffffff8164106e>] __x64_sys_mount+0x18e/0x1d0 fs/namespace.c:3568
    [<ffffffff8485b285>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff8485b285>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff84a00087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

BUG: memory leak
unreferenced object 0xffff88810c91f040 (size 64):
  comm "syz-executor193", pid 3787, jiffies 4294971495 (age 12.820s)
  hex dump (first 32 bytes):
    03 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
    01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff814ed790>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1045
    [<ffffffff82086355>] kmalloc include/linux/slab.h:553 [inline]
    [<ffffffff82086355>] kzalloc include/linux/slab.h:689 [inline]
    [<ffffffff82086355>] add_block_entry+0x35/0x320 fs/btrfs/ref-verify.c:267
    [<ffffffff82086a0e>] add_tree_block+0x9e/0x210 fs/btrfs/ref-verify.c:329
    [<ffffffff82087e7c>] btrfs_build_ref_tree+0x50c/0x750 fs/btrfs/ref-verify.c:471
    [<ffffffff846b818d>] open_ctree+0x19af/0x1fcb fs/btrfs/disk-io.c:3767
    [<ffffffff846b17d6>] btrfs_fill_super fs/btrfs/super.c:1461 [inline]
    [<ffffffff846b17d6>] btrfs_mount_root.cold+0x13/0xf5 fs/btrfs/super.c:1829
    [<ffffffff81662b0b>] legacy_get_tree+0x2b/0x90 fs/fs_context.c:610
    [<ffffffff815fc948>] vfs_get_tree+0x28/0x100 fs/super.c:1531
    [<ffffffff81638b61>] fc_mount fs/namespace.c:1043 [inline]
    [<ffffffff81638b61>] vfs_kern_mount.part.0+0xd1/0x120 fs/namespace.c:1073
    [<ffffffff81638bec>] vfs_kern_mount+0x3c/0x60 fs/namespace.c:1060
    [<ffffffff81f54029>] btrfs_mount+0x199/0x590 fs/btrfs/super.c:1889
    [<ffffffff81662b0b>] legacy_get_tree+0x2b/0x90 fs/fs_context.c:610
    [<ffffffff815fc948>] vfs_get_tree+0x28/0x100 fs/super.c:1531
    [<ffffffff81640487>] do_new_mount fs/namespace.c:3040 [inline]
    [<ffffffff81640487>] path_mount+0xc37/0x10d0 fs/namespace.c:3370
    [<ffffffff8164106e>] do_mount fs/namespace.c:3383 [inline]
    [<ffffffff8164106e>] __do_sys_mount fs/namespace.c:3591 [inline]
    [<ffffffff8164106e>] __se_sys_mount fs/namespace.c:3568 [inline]
    [<ffffffff8164106e>] __x64_sys_mount+0x18e/0x1d0 fs/namespace.c:3568
    [<ffffffff8485b285>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff8485b285>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80

BUG: memory leak
unreferenced object 0xffff88810caab580 (size 96):
  comm "syz-executor193", pid 3787, jiffies 4294971495 (age 12.820s)
  hex dump (first 32 bytes):
    00 10 10 00 00 00 00 00 00 10 00 00 00 00 00 00  ................
    01 00 00 00 00 00 00 00 01 00 00 00 01 00 00 00  ................
  backtrace:
    [<ffffffff814ed790>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1045
    [<ffffffff8208636e>] kmalloc include/linux/slab.h:553 [inline]
    [<ffffffff8208636e>] kzalloc include/linux/slab.h:689 [inline]
    [<ffffffff8208636e>] add_block_entry+0x4e/0x320 fs/btrfs/ref-verify.c:268
    [<ffffffff82086a0e>] add_tree_block+0x9e/0x210 fs/btrfs/ref-verify.c:329
    [<ffffffff82087e7c>] btrfs_build_ref_tree+0x50c/0x750 fs/btrfs/ref-verify.c:471
    [<ffffffff846b818d>] open_ctree+0x19af/0x1fcb fs/btrfs/disk-io.c:3767
    [<ffffffff846b17d6>] btrfs_fill_super fs/btrfs/super.c:1461 [inline]
    [<ffffffff846b17d6>] btrfs_mount_root.cold+0x13/0xf5 fs/btrfs/super.c:1829
    [<ffffffff81662b0b>] legacy_get_tree+0x2b/0x90 fs/fs_context.c:610
    [<ffffffff815fc948>] vfs_get_tree+0x28/0x100 fs/super.c:1531
    [<ffffffff81638b61>] fc_mount fs/namespace.c:1043 [inline]
    [<ffffffff81638b61>] vfs_kern_mount.part.0+0xd1/0x120 fs/namespace.c:1073
    [<ffffffff81638bec>] vfs_kern_mount+0x3c/0x60 fs/namespace.c:1060
    [<ffffffff81f54029>] btrfs_mount+0x199/0x590 fs/btrfs/super.c:1889
    [<ffffffff81662b0b>] legacy_get_tree+0x2b/0x90 fs/fs_context.c:610
    [<ffffffff815fc948>] vfs_get_tree+0x28/0x100 fs/super.c:1531
    [<ffffffff81640487>] do_new_mount fs/namespace.c:3040 [inline]
    [<ffffffff81640487>] path_mount+0xc37/0x10d0 fs/namespace.c:3370
    [<ffffffff8164106e>] do_mount fs/namespace.c:3383 [inline]
    [<ffffffff8164106e>] __do_sys_mount fs/namespace.c:3591 [inline]
    [<ffffffff8164106e>] __se_sys_mount fs/namespace.c:3568 [inline]
    [<ffffffff8164106e>] __x64_sys_mount+0x18e/0x1d0 fs/namespace.c:3568
    [<ffffffff8485b285>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff8485b285>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80



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