Re: [syzbot] [btrfs?] memory leak in add_tree_block

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
memory leak in add_tree_block

BUG: memory leak
unreferenced object 0xffff88811b83f780 (size 64):
  comm "syz-executor.0", pid 5490, jiffies 4294945002 (age 8.100s)
  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:
    [<ffffffff81578015>] kmalloc_trace+0x25/0x90 mm/slab_common.c:1098
    [<ffffffff821ae7a9>] kmalloc include/linux/slab.h:600 [inline]
    [<ffffffff821ae7a9>] add_tree_block+0x39/0x240 fs/btrfs/ref-verify.c:319
    [<ffffffff821afdb6>] process_extent_item fs/btrfs/ref-verify.c:474 [inline]
    [<ffffffff821afdb6>] process_leaf fs/btrfs/ref-verify.c:524 [inline]
    [<ffffffff821afdb6>] walk_down_tree fs/btrfs/ref-verify.c:576 [inline]
    [<ffffffff821afdb6>] btrfs_build_ref_tree+0x566/0x8c0 fs/btrfs/ref-verify.c:1009
    [<ffffffff82095365>] open_ctree+0x18c5/0x2370 fs/btrfs/disk-io.c:3523
    [<ffffffff8205ab21>] btrfs_fill_super fs/btrfs/super.c:1117 [inline]
    [<ffffffff8205ab21>] btrfs_mount_root+0x5a1/0x750 fs/btrfs/super.c:1478
    [<ffffffff816fd5a9>] legacy_get_tree+0x29/0x80 fs/fs_context.c:662
    [<ffffffff81692d2a>] vfs_get_tree+0x2a/0x130 fs/super.c:1768
    [<ffffffff816d06db>] fc_mount fs/namespace.c:1114 [inline]
    [<ffffffff816d06db>] vfs_kern_mount.part.0+0xcb/0x110 fs/namespace.c:1144
    [<ffffffff816d075f>] vfs_kern_mount+0x3f/0x60 fs/namespace.c:1131
    [<ffffffff8205eb82>] btrfs_mount+0x1e2/0x660 fs/btrfs/super.c:1538
    [<ffffffff816fd5a9>] legacy_get_tree+0x29/0x80 fs/fs_context.c:662
    [<ffffffff81692d2a>] vfs_get_tree+0x2a/0x130 fs/super.c:1768
    [<ffffffff816d882f>] do_new_mount fs/namespace.c:3337 [inline]
    [<ffffffff816d882f>] path_mount+0xc8f/0x10d0 fs/namespace.c:3664
    [<ffffffff816d9421>] do_mount fs/namespace.c:3677 [inline]
    [<ffffffff816d9421>] __do_sys_mount fs/namespace.c:3886 [inline]
    [<ffffffff816d9421>] __se_sys_mount fs/namespace.c:3863 [inline]
    [<ffffffff816d9421>] __x64_sys_mount+0x1a1/0x1f0 fs/namespace.c:3863
    [<ffffffff84b4945f>] do_syscall_x64 arch/x86/entry/common.c:51 [inline]
    [<ffffffff84b4945f>] do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:82
    [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0x6b

BUG: memory leak
unreferenced object 0xffff88811b83fe40 (size 64):
  comm "syz-executor.0", pid 5490, jiffies 4294945002 (age 8.100s)
  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:
    [<ffffffff81578015>] kmalloc_trace+0x25/0x90 mm/slab_common.c:1098
    [<ffffffff821ae165>] kmalloc include/linux/slab.h:600 [inline]
    [<ffffffff821ae165>] kzalloc include/linux/slab.h:721 [inline]
    [<ffffffff821ae165>] add_block_entry+0x35/0x320 fs/btrfs/ref-verify.c:270
    [<ffffffff821ae806>] add_tree_block+0x96/0x240 fs/btrfs/ref-verify.c:332
    [<ffffffff821afdb6>] process_extent_item fs/btrfs/ref-verify.c:474 [inline]
    [<ffffffff821afdb6>] process_leaf fs/btrfs/ref-verify.c:524 [inline]
    [<ffffffff821afdb6>] walk_down_tree fs/btrfs/ref-verify.c:576 [inline]
    [<ffffffff821afdb6>] btrfs_build_ref_tree+0x566/0x8c0 fs/btrfs/ref-verify.c:1009
    [<ffffffff82095365>] open_ctree+0x18c5/0x2370 fs/btrfs/disk-io.c:3523
    [<ffffffff8205ab21>] btrfs_fill_super fs/btrfs/super.c:1117 [inline]
    [<ffffffff8205ab21>] btrfs_mount_root+0x5a1/0x750 fs/btrfs/super.c:1478
    [<ffffffff816fd5a9>] legacy_get_tree+0x29/0x80 fs/fs_context.c:662
    [<ffffffff81692d2a>] vfs_get_tree+0x2a/0x130 fs/super.c:1768
    [<ffffffff816d06db>] fc_mount fs/namespace.c:1114 [inline]
    [<ffffffff816d06db>] vfs_kern_mount.part.0+0xcb/0x110 fs/namespace.c:1144
    [<ffffffff816d075f>] vfs_kern_mount+0x3f/0x60 fs/namespace.c:1131
    [<ffffffff8205eb82>] btrfs_mount+0x1e2/0x660 fs/btrfs/super.c:1538
    [<ffffffff816fd5a9>] legacy_get_tree+0x29/0x80 fs/fs_context.c:662
    [<ffffffff81692d2a>] vfs_get_tree+0x2a/0x130 fs/super.c:1768
    [<ffffffff816d882f>] do_new_mount fs/namespace.c:3337 [inline]
    [<ffffffff816d882f>] path_mount+0xc8f/0x10d0 fs/namespace.c:3664
    [<ffffffff816d9421>] do_mount fs/namespace.c:3677 [inline]
    [<ffffffff816d9421>] __do_sys_mount fs/namespace.c:3886 [inline]
    [<ffffffff816d9421>] __se_sys_mount fs/namespace.c:3863 [inline]
    [<ffffffff816d9421>] __x64_sys_mount+0x1a1/0x1f0 fs/namespace.c:3863
    [<ffffffff84b4945f>] do_syscall_x64 arch/x86/entry/common.c:51 [inline]
    [<ffffffff84b4945f>] do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:82

BUG: memory leak
unreferenced object 0xffff88811acefb40 (size 96):
  comm "syz-executor.0", pid 5490, jiffies 4294945002 (age 8.100s)
  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:
    [<ffffffff81578015>] kmalloc_trace+0x25/0x90 mm/slab_common.c:1098
    [<ffffffff821ae17e>] kmalloc include/linux/slab.h:600 [inline]
    [<ffffffff821ae17e>] kzalloc include/linux/slab.h:721 [inline]
    [<ffffffff821ae17e>] add_block_entry+0x4e/0x320 fs/btrfs/ref-verify.c:271
    [<ffffffff821ae806>] add_tree_block+0x96/0x240 fs/btrfs/ref-verify.c:332
    [<ffffffff821afdb6>] process_extent_item fs/btrfs/ref-verify.c:474 [inline]
    [<ffffffff821afdb6>] process_leaf fs/btrfs/ref-verify.c:524 [inline]
    [<ffffffff821afdb6>] walk_down_tree fs/btrfs/ref-verify.c:576 [inline]
    [<ffffffff821afdb6>] btrfs_build_ref_tree+0x566/0x8c0 fs/btrfs/ref-verify.c:1009
    [<ffffffff82095365>] open_ctree+0x18c5/0x2370 fs/btrfs/disk-io.c:3523
    [<ffffffff8205ab21>] btrfs_fill_super fs/btrfs/super.c:1117 [inline]
    [<ffffffff8205ab21>] btrfs_mount_root+0x5a1/0x750 fs/btrfs/super.c:1478
    [<ffffffff816fd5a9>] legacy_get_tree+0x29/0x80 fs/fs_context.c:662
    [<ffffffff81692d2a>] vfs_get_tree+0x2a/0x130 fs/super.c:1768
    [<ffffffff816d06db>] fc_mount fs/namespace.c:1114 [inline]
    [<ffffffff816d06db>] vfs_kern_mount.part.0+0xcb/0x110 fs/namespace.c:1144
    [<ffffffff816d075f>] vfs_kern_mount+0x3f/0x60 fs/namespace.c:1131
    [<ffffffff8205eb82>] btrfs_mount+0x1e2/0x660 fs/btrfs/super.c:1538
    [<ffffffff816fd5a9>] legacy_get_tree+0x29/0x80 fs/fs_context.c:662
    [<ffffffff81692d2a>] vfs_get_tree+0x2a/0x130 fs/super.c:1768
    [<ffffffff816d882f>] do_new_mount fs/namespace.c:3337 [inline]
    [<ffffffff816d882f>] path_mount+0xc8f/0x10d0 fs/namespace.c:3664
    [<ffffffff816d9421>] do_mount fs/namespace.c:3677 [inline]
    [<ffffffff816d9421>] __do_sys_mount fs/namespace.c:3886 [inline]
    [<ffffffff816d9421>] __se_sys_mount fs/namespace.c:3863 [inline]
    [<ffffffff816d9421>] __x64_sys_mount+0x1a1/0x1f0 fs/namespace.c:3863
    [<ffffffff84b4945f>] do_syscall_x64 arch/x86/entry/common.c:51 [inline]
    [<ffffffff84b4945f>] do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:82



Tested on:

commit:         5a6a09e9 Merge tag 'cgroup-for-6.7' of git://git.kerne..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=161484b8e80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=492c9379bc08e464
dashboard link: https://syzkaller.appspot.com/bug?extid=be14ed7728594dc8bd42
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.