CVE-2023-53865
Description
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix warning when putting transaction with qgroups enabled after abort
If we have a transaction abort with qgroups enabled we get a warning triggered when doing the final put on the transaction, like this:
[552.6789] ------------[ cut here ]------------ [552.6815] WARNING: CPU: 4 PID: 81745 at fs/btrfs/transaction.c:144 btrfs_put_transaction+0x123/0x130 [btrfs] [552.6817] Modules linked in: btrfs blake2b_generic xor (...) [552.6819] CPU: 4 PID: 81745 Comm: btrfs-transacti Tainted: G W 6.4.0-rc6-btrfs-next-134+ #1 [552.6819] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014 [552.6819] RIP: 0010:btrfs_put_transaction+0x123/0x130 [btrfs] [552.6821] Code: bd a0 01 00 (...) [552.6821] RSP: 0018:ffffa168c0527e28 EFLAGS: 00010286 [552.6821] RAX: ffff936042caed00 RBX: ffff93604a3eb448 RCX: 0000000000000000 [552.6821] RDX: ffff93606421b028 RSI: ffffffff92ff0878 RDI: ffff93606421b010 [552.6821] RBP: ffff93606421b000 R08: 0000000000000000 R09: ffffa168c0d07c20 [552.6821] R10: 0000000000000000 R11: ffff93608dc52950 R12: ffffa168c0527e70 [552.6821] R13: ffff93606421b000 R14: ffff93604a3eb420 R15: ffff93606421b028 [552.6821] FS: 0000000000000000(0000) GS:ffff93675fb00000(0000) knlGS:0000000000000000 [552.6821] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [552.6821] CR2: 0000558ad262b000 CR3: 000000014feda005 CR4: 0000000000370ee0 [552.6822] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [552.6822] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [552.6822] Call Trace: [552.6822] [552.6822] ? __warn+0x80/0x130 [552.6822] ? btrfs_put_transaction+0x123/0x130 [btrfs] [552.6824] ? report_bug+0x1f4/0x200 [552.6824] ? handle_bug+0x42/0x70 [552.6824] ? exc_invalid_op+0x14/0x70 [552.6824] ? asm_exc_invalid_op+0x16/0x20 [552.6824] ? btrfs_put_transaction+0x123/0x130 [btrfs] [552.6826] btrfs_cleanup_transaction+0xe7/0x5e0 [btrfs] [552.6828] ? _raw_spin_unlock_irqrestore+0x23/0x40 [552.6828] ? try_to_wake_up+0x94/0x5e0 [552.6828] ? __pfx_process_timeout+0x10/0x10 [552.6828] transaction_kthread+0x103/0x1d0 [btrfs] [552.6830] ? __pfx_transaction_kthread+0x10/0x10 [btrfs] [552.6832] kthread+0xee/0x120 [552.6832] ? __pfx_kthread+0x10/0x10 [552.6832] ret_from_fork+0x29/0x50 [552.6832] [552.6832] ---[ end trace 0000000000000000 ]---
This corresponds to this line of code:
void btrfs_put_transaction(struct btrfs_transaction *transaction) { (...) WARN_ON(!RB_EMPTY_ROOT( &transaction->delayed_refs.dirty_extent_root)); (...) }
The warning happens because btrfs_qgroup_destroy_extent_records(), called in the transaction abort path, we free all entries from the rbtree "dirty_extent_root" with rbtree_postorder_for_each_entry_safe(), but we don't actually empty the rbtree - it's still pointing to nodes that were freed.
So set the rbtree's root node to NULL to avoid this warning (assign RB_ROOT).
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
In the Linux kernel, a warning occurs in btrfs when putting a transaction with qgroups enabled after an abort, potentially causing system instability.
Vulnerability
Description
CVE-2023-53865 is a bug in the Linux kernel's btrfs filesystem that triggers a warning when a transaction is finalized after an abort if quota groups (qgroups) are enabled. The warning is issued in the btrfs_put_transaction function when certain conditions are not met during transaction cleanup [1].
Attack
Vector
An attacker with local access and the ability to trigger a btrfs transaction abort (e.g., via deliberate filesystem operations or triggering errors) can cause this warning to fire. No special privileges beyond normal filesystem access are required, but the attacker must be able to influence the filesystem state to cause an abort while qgroups are active [2].
Impact
The warning itself is not directly exploitable for data corruption or privilege escalation, but it indicates a kernel bug that can lead to system instability, lockups, or denial of service. Repeated warnings could flood system logs and degrade performance [3].
Mitigation
The issue is fixed by kernel patches that ensure proper handling of the transaction state when qgroups are enabled. Users should apply the latest stable kernel updates containing commits [1], [2], [3], and [4] to eliminate the warning. No workaround is available for unpatched systems.
AI Insight generated on May 19, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected products
2Patches
6ae91ab710d8ed2c667cc1831c9060caab41389e994688e9662dd82bc7a90aa84ce8a78a1Vulnerability mechanics
Generated on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.
References
6- git.kernel.org/stable/c/62dd82bc7a90b5052c062a0ad5be6d8a479a3cfbnvd
- git.kernel.org/stable/c/89e994688e965813ec0a09fb30b87fb8cee06474nvd
- git.kernel.org/stable/c/aa84ce8a78a1a5c10cdf9c7a5fb0c999fbc2c8d6nvd
- git.kernel.org/stable/c/ae91ab710d8e309f6c9eba07ce0d9d0b5d9040f0nvd
- git.kernel.org/stable/c/c9060caab4135dd660c4676d1ea33a6e0d3fc09dnvd
- git.kernel.org/stable/c/d2c667cc18314c9bad3ec86ae071c0342132aa09nvd
News mentions
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