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

ext4: fix circular lock dependency in ext4_ext_migrate

Move iput(tmp_inode) after ext4_writepages_up_write() to avoid a
circular lock dependency between s_writepages_rwsem and sb_internal
(freeze protection).

The deadlock scenario:

CPU0 (EXT4_IOC_MIGRATE) CPU1 (orphan cleanup during mount)
---- ----
ext4_ext_migrate()
ext4_writepages_down_write()
s_writepages_rwsem (write)
ext4_evict_inode()
sb_start_intwrite() [sb_internal]
...
ext4_writepages()
s_writepages_rwsem (read) [BLOCKED]
iput(tmp_inode)
ext4_evict_inode()
sb_start_intwrite() [BLOCKED]

The tmp_inode is a temporary inode with nlink=0 created solely for
building the extent tree. Its eviction does not require
s_writepages_rwsem protection, so deferring iput() until after
releasing the rwsem is safe.

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History

Thu, 24 Sep 2026 16:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ext4: fix circular lock dependency in ext4_ext_migrate Move iput(tmp_inode) after ext4_writepages_up_write() to avoid a circular lock dependency between s_writepages_rwsem and sb_internal (freeze protection). The deadlock scenario: CPU0 (EXT4_IOC_MIGRATE) CPU1 (orphan cleanup during mount) ---- ---- ext4_ext_migrate() ext4_writepages_down_write() s_writepages_rwsem (write) ext4_evict_inode() sb_start_intwrite() [sb_internal] ... ext4_writepages() s_writepages_rwsem (read) [BLOCKED] iput(tmp_inode) ext4_evict_inode() sb_start_intwrite() [BLOCKED] The tmp_inode is a temporary inode with nlink=0 created solely for building the extent tree. Its eviction does not require s_writepages_rwsem protection, so deferring iput() until after releasing the rwsem is safe.
Title ext4: fix circular lock dependency in ext4_ext_migrate
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-24T15:52:09.047Z

Reserved: 2026-09-17T16:02:15.097Z

Link: CVE-2026-93269

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-24T16:17:23.873

Modified: 2026-09-24T16:17:23.873

Link: CVE-2026-93269

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

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