[syzbot] [btrfs?] memory leak in btrfs_ref_tree_mod

From: syzbot
Date: Tue Aug 15 2023 - 05:16:14 EST


Hello,

syzbot found the following issue on:

HEAD commit: 25aa0bebba72 Merge tag 'net-6.5-rc6' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=169577fda80000
kernel config: https://syzkaller.appspot.com/x/.config?x=2bf8962e4f7984f4
dashboard link: https://syzkaller.appspot.com/bug?extid=d66de4cbf532749df35f
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=148191c3a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/76b0857d2814/disk-25aa0beb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a01574755257/vmlinux-25aa0beb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/262002db770e/bzImage-25aa0beb.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/b93cffaa6717/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d66de4cbf532749df35f@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: memory leak
unreferenced object 0xffff888129851240 (size 64):
comm "syz-executor.0", pid 5069, jiffies 4294977377 (age 16.480s)
hex dump (first 32 bytes):
01 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:
[<ffffffff815545e5>] kmalloc_trace+0x25/0x90 mm/slab_common.c:1076
[<ffffffff821731b1>] kmalloc include/linux/slab.h:582 [inline]
[<ffffffff821731b1>] btrfs_ref_tree_mod+0x211/0xb80 fs/btrfs/ref-verify.c:768
[<ffffffff820444f6>] btrfs_free_tree_block+0x116/0x450 fs/btrfs/extent-tree.c:3250
[<ffffffff8202d775>] __btrfs_cow_block+0x6a5/0xa30 fs/btrfs/ctree.c:601
[<ffffffff8202dc54>] btrfs_cow_block+0x154/0x2b0 fs/btrfs/ctree.c:712
[<ffffffff8206013c>] commit_cowonly_roots+0x8c/0x3f0 fs/btrfs/transaction.c:1276
[<ffffffff820647c9>] btrfs_commit_transaction+0x999/0x15c0 fs/btrfs/transaction.c:2410
[<ffffffff8205a516>] btrfs_commit_super+0x86/0xb0 fs/btrfs/disk-io.c:4195
[<ffffffff8205c743>] close_ctree+0x543/0x730 fs/btrfs/disk-io.c:4349
[<ffffffff8166b44e>] generic_shutdown_super+0x9e/0x1c0 fs/super.c:499
[<ffffffff8166b769>] kill_anon_super+0x19/0x30 fs/super.c:1110
[<ffffffff8202357d>] btrfs_kill_super+0x1d/0x30 fs/btrfs/super.c:2138
[<ffffffff8166ca46>] deactivate_locked_super+0x46/0xd0 fs/super.c:330
[<ffffffff8166cb6c>] deactivate_super fs/super.c:361 [inline]
[<ffffffff8166cb6c>] deactivate_super+0x9c/0xb0 fs/super.c:357
[<ffffffff816a8931>] cleanup_mnt+0x121/0x210 fs/namespace.c:1254
[<ffffffff812becaf>] task_work_run+0x8f/0xe0 kernel/task_work.c:179



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