Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: io_uring/poll: fix signed comparison in io_poll_get_ownership() io_poll_get_ownership() uses a signed comparison to check whether poll_refs has reached the threshold for the slowpath: if (unlikely(atomic_read(&req->poll_refs) >= IO_POLL_REF_BIAS)) atomic_read() returns int (signed). When IO_POLL_CANCEL_FLAG (BIT(31)) is set in poll_refs, the value becomes negative in signed arithmetic, so the >= 128 comparison always evaluates to false and the slowpath is never taken. Fix this by casting the atomic_read() result to unsigned int before the comparison, so that the cancel flag is treated as a large positive value and correctly triggers the slowpath.

Affected versions

Linux: a26a35e9019fd70bf3cf647dcfdae87abc7bacea through before 81bf96b0abbfa4cd47ea32e12596aed3855fb2f3 (git); a26a35e9019fd70bf3cf647dcfdae87abc7bacea through before cf522703d4f194991615763697ae25a3f9539763 (git); a26a35e9019fd70bf3cf647dcfdae87abc7bacea through before fc47043f3d9af3efa407665b47f8378ec691ba18 (git); a26a35e9019fd70bf3cf647dcfdae87abc7bacea through before ea0697129807d718037f618221037aa0660ee3c5 (git); a26a35e9019fd70bf3cf647dcfdae87abc7bacea through before c6d191164dc81838d8dbf452a6000f68c558d1ae (git); a26a35e9019fd70bf3cf647dcfdae87abc7bacea through before 326941b22806cbf2df1fbfe902b7908b368cce42 (git); 4b702b7d11ce1b9d26fc6d7c5a7ef4ac1d455048 (git); bc4e6ee16778149811333a969a7a893d4cc110c5 (git); 5.15.82 through before 5.16 (semver); 6.0.11 through before 6.1 (semver); 6.1; V3.1.6 through before * (custom) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.