CVE-2025-21832: block: don't revert iter for -EIOCBQUEUED

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-03-06 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: block: don't revert iter for -EIOCBQUEUED blkdev_read_iter() has a few odd checks, like gating the position and count adjustment on whether or not the result is bigger-than-or-equal to zero (where bigger than makes more sense), and not checking the return value of blkdev_direct_IO() before doing an iov_iter_revert(). The latter can lead to attempting to revert with a negative value, which when passed to iov_iter_revert() as an unsigned value will lead to throwing a WARN_ON() because unroll is bigger than MAX_RW_COUNT. Be sane and don't revert for -EIOCBQUEUED, like what is done in other spots.

Affected products

Linux kernel: from 5.17.1 before 6.1.129; from 6.2 before 6.6.78; from 6.7 before 6.12.14; from 6.13 before 6.13.3; 5.17, 5.17-rc3, 5.17-rc4, 5.17-rc5, 5.17-rc6, 5.17-rc7 (+1) — fixed in 6.1.129, 6.12.14, 6.13.3, 6.6.78

How to fix

Upgrade to a fixed version: Linux kernel 6.1.129, 6.12.14, 6.13.3, 6.6.78. Check the vendor advisory for mitigations.

References

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