CVE-2025-21754 — btrfs: fix assertion failure when splitting ordered extent after transaction abort

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix assertion failure when splitting ordered extent after transaction abort

If while we are doing a direct IO write a transaction abort happens, we mark all existing ordered extents with the BTRFS_ORDERED_IOERR flag (done at btrfs_destroy_ordered_extents()), and then after that if we enter btrfs_split_ordered_extent() and the ordered extent has bytes left (meaning we have a bio that doesn't cover the whole ordered extent, see details at btrfs_extract_ordered_extent()), we will fail on the following assertion at btrfs_split_ordered_extent():

ASSERT(!(flags & ~BTRFS_ORDERED_TYPE_FLAGS));

because the BTRFS_ORDERED_IOERR flag is set and the definition of BTRFS_ORDERED_TYPE_FLAGS is just the union of all flags that identify the type of write (regular, nocow, prealloc, compressed, direct IO, encoded).

Fix this by returning an error from btrfs_extract_ordered_extent() if we find the BTRFS_ORDERED_IOERR flag in the ordered extent. The error will be the error that resulted in the transaction abort or -EIO if no transaction abort happened.

This was recently reported by syzbot with the following trace:

FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 1 CPU: 0 UID: 0 PID: 5321 Comm: syz.0.0 Not tainted 6.13.0-rc5-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: <TASK>…

USN-7521-1 — linux, linux-azure, linux-azure-6.11, linux-gcp, linux-gcp-6.11, linux-hwe-6.11, linux-oem-6.11, linux-raspi, linux-rea…

Affected: Ubuntu:24.04:LTS: linux-azure-6.11, Ubuntu:24.04:LTS: linux-gcp-6.11, Ubuntu:24.04:LTS: linux-hwe-6.11, Ubuntu:24.04:LTS: linux-oem-6.11

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - ARM64 architecture; - PowerPC architecture; - x86 architecture; - Block layer subsystem; - Serial ATA and Parallel ATA drivers; - Drivers core; - Network block device driver; - Bluetooth drivers; - Character device driver; - TPM device driver; - Clock framework and drivers; - Hardware crypto device drivers; - FireWire subsystem; - EFI core; - Qualcomm firmware drivers; - GPIO subsystem; - GPU drivers; - HID subsystem; - I2C subsystem; - I3C subsystem; - InfiniBand drivers; - Input Device (Mouse) drivers; - IOMMU subsystem; - Multiple devices driver; - Media drivers; - NVIDIA Tegra memory controller driver; - Fastrpc Driver; - Network drivers; - Operating Performance Points (OPP) driver; - PCI subsystem; - x86 platform drivers; - PPS (Pulse Per Second) driver; - PTP clock framework; - Remote Processor subsystem; - Real Time Clock drivers; - S/390 drivers; - SCSI subsystem; - QCOM SoC drivers; - SPI subsystem; - Media staging drivers; - Trusted Execution Environment drivers; - TTY drivers; - UFS subsystem; - USB Device Class drivers; - USB core drivers; - USB Gadget drivers; - USB Host Controller drivers; - Framebuffer layer; - File systems infrastructure; - BTRFS file system; - Ceph distributed fi…

Most recent entries from all

CVE-2025-21754 — btrfs: fix assertion failure when splitting ordered extent after transaction abort

USN-7521-1 — linux, linux-azure, linux-azure-6.11, linux-gcp, linux-gcp-6.11, linux-hwe-6.11, linux-oem-6.11, linux-raspi, linux-rea…