CVE-2026-53284
Received Received - Intake
Buffer Overflow in Linux Kernel Btrfs

Publication date: 2026-06-26

Last updated on: 2026-06-26

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: btrfs: only release the dirty pages io tree after successful writes [WARNING] With extra warning on dirty extent buffers at umount (aka, the next patch in the series), test case generic/388 can trigger the following warning about dirty extent buffers at unmount time: BTRFS critical (device dm-2 state E): emergency shutdown BTRFS error (device dm-2 state E): error while writing out transaction: -30 BTRFS warning (device dm-2 state E): Skipping commit of aborted transaction. BTRFS error (device dm-2 state EA): Transaction 9 aborted (error -30) BTRFS: error (device dm-2 state EA) in cleanup_transaction:2068: errno=-30 Readonly filesystem BTRFS info (device dm-2 state EA): forced readonly BTRFS info (device dm-2 state EA): last unmount of filesystem 4fbf2e15-f941-49a0-bc7c-716315d2777c ------------[ cut here ]------------ WARNING: disk-io.c:3311 at invalidate_and_check_btree_folios+0xfd/0x1ca [btrfs], CPU#8: umount/914368 CPU: 8 UID: 0 PID: 914368 Comm: umount Tainted: G OE 7.1.0-rc1-custom+ #372 PREEMPT(full) 2de38db8d1deae71fde295430a0ff3ab98ccf596 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022 RIP: 0010:invalidate_and_check_btree_folios+0xfd/0x1ca [btrfs] Call Trace: <TASK> close_ctree+0x52e/0x574 [btrfs d2f0b1cd330d1287e7a9919d112eadfc0e914efd] generic_shutdown_super+0x89/0x1a0 kill_anon_super+0x16/0x40 btrfs_kill_super+0x16/0x20 [btrfs d2f0b1cd330d1287e7a9919d112eadfc0e914efd] deactivate_locked_super+0x2d/0xb0 cleanup_mnt+0xdc/0x140 task_work_run+0x5a/0xa0 exit_to_user_mode_loop+0x123/0x4b0 do_syscall_64+0x243/0x7c0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 </TASK> ---[ end trace 0000000000000000 ]--- BTRFS warning (device dm-2 state EA): unable to release extent buffer 30539776 owner 9 gen 9 refs 2 flags 0x7 BTRFS warning (device dm-2 state EA): unable to release extent buffer 30621696 owner 257 gen 9 refs 2 flags 0x7 BTRFS warning (device dm-2 state EA): unable to release extent buffer 30638080 owner 258 gen 9 refs 2 flags 0x7 BTRFS warning (device dm-2 state EA): unable to release extent buffer 30654464 owner 7 gen 9 refs 2 flags 0x7 BTRFS warning (device dm-2 state EA): unable to release extent buffer 30703616 owner 2 gen 9 refs 2 flags 0x7 BTRFS warning (device dm-2 state EA): unable to release extent buffer 30720000 owner 10 gen 9 refs 2 flags 0x7 BTRFS warning (device dm-2 state EA): unable to release extent buffer 30736384 owner 4 gen 9 refs 2 flags 0x7 BTRFS warning (device dm-2 state EA): unable to release extent buffer 30752768 owner 11 gen 9 refs 2 flags 0x7 I'm using a stripped down version, which seems to trigger the warning more reliably: _fsstress_pid="" workload() { dmesg -C mkfs.btrfs -f -K $dev > /dev/null echo 1 > /sys/kernel/debug/clear_warn_once mount $dev $mnt $fsstress -w -n 1024 -p 4 -d $mnt & _fsstress_pid=$! sleep 0 $godown $mnt pkill --echo -PIPE fsstress > /dev/null wait $_fsstress_pid unset _fsstress_pid umount $mnt if dmesg | grep -q "WARNING"; then fail fi } for (( i = 0; i < $runtime; i++ )); do echo "=== $i/$runtime ===" workload done [CAUSE] Inside btrfs_write_and_wait_transaction(), we first try to write all dirty ebs, then wait for them to finish. After that we call btrfs_extent_io_tree_release() to free all extent states from dirty_pages io tree. However if we hit an error from btrfs_write_marked_extent(), then we still call btrfs_extent_io_tree_release() to clear that dirty_pages io tree, which may contain dirty records that we haven't yet submitted. Furthermore, the later transaction cleanup path will utilize that dirty_pages io tree to properly cleanup those dirty ebs, but since it's already empty, no dirty ebs are properly cleaned up, thus will later trigger the warnings inside invalidate_btree_folios(). ---truncated---
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Meta Information
Published
2026-06-26
Last Modified
2026-06-26
Generated
2026-06-27
AI Q&A
2026-06-26
EPSS Evaluated
N/A
NVD
CVE-2026-53284
EUVD
EUVD-2026-39889
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel 7.1.0-rc1-custom
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Exploitability
CWE
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's btrfs filesystem. It occurs because the system releases the dirty pages io tree even after a failed write operation. Specifically, when writing dirty extent buffers, if an error happens during the write, the code still clears the dirty pages io tree, which may still contain dirty records that were not successfully written. Later, when the system tries to clean up these dirty extent buffers, it finds the tree empty and cannot properly clean them up, leading to warnings and errors during unmount operations.

This issue can trigger critical warnings and errors such as emergency shutdowns, aborted transactions, and forced readonly states of the filesystem, as indicated by kernel messages during unmount.

Impact Analysis

The vulnerability can cause the btrfs filesystem to enter an emergency shutdown state and become readonly unexpectedly. This can lead to aborted transactions and errors when writing data, potentially resulting in data loss or corruption.

Users may experience system instability or failure to properly unmount the filesystem, which can disrupt normal operations and require manual intervention to recover the filesystem.

Detection Guidance

This vulnerability can be detected by monitoring system logs for specific BTRFS warnings and errors related to dirty extent buffers and transaction aborts during unmount operations.

  • Check the kernel message buffer for BTRFS warnings using the command: dmesg | grep -i btrfs
  • Look specifically for warnings such as 'dirty extent buffers at unmount time', 'emergency shutdown', 'error while writing out transaction', 'Transaction aborted', and 'forced readonly' states.
  • Use the provided test workload script approach to reproduce the issue by running filesystem stress tests and monitoring dmesg for warnings.
Mitigation Strategies

Immediate mitigation involves applying the patch that fixes the issue by ensuring that dirty pages io tree is only released after successful writes.

Until the patch is applied, avoid unmounting BTRFS filesystems under heavy write stress or during ongoing transactions to reduce the chance of triggering the warnings and errors.

Monitor system logs for the described warnings and errors to detect if the issue is occurring and plan for kernel updates accordingly.

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