CVE-2026-98079

CVE CVE-2026-98079EUVD EUVD-2026-86909Published 2026-09-25T10:24:16.000Z

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: btrfs: zstd: fix lost wakeup when waiting for a workspace A writer can sleep forever in zstd_get_workspace() even though a workspace is free. When zstd_alloc_workspace() fails, the task is queued on zwsm->wait and schedules unconditionally, never re-testing the pool. zstd_put_workspace() publishes the workspace and then calls cond_wake_up(), which only wakes when a sleeper is already visible, so a workspace returned between the failed allocation and prepare_to_wait() wakes nobody. The window is wide: zstd_alloc_workspace() goes through kvmalloc() and may enter reclaim. Only a max level workspace triggers the wakeup and one is deliberately kept allocated as the fallback every waiter waits for, so once its wakeup is lost the writer stays in TASK_UNINTERRUPTIBLE until some other task happens to return one. Re-check the pool after prepare_to_wait() has published the waiter, and use the workspace if one turned up.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

Linux — Linux 5.1; 3f93aef535c8ea03e40cd8acf0753b3e6ed33e96 <0de9f31d447ae71ab08c7850a321682f8d2907c3; patch: 7.2.7; 3f93aef535c8ea03e40cd8acf0753b3e6ed33e96 <2acb9f3d1cc8f65dc81ed55e238cbf8e5b60bff7; patch: 6.18.53; patch: 7.3-rc2; 3f93aef535c8ea03e40cd8acf0753b3e6ed33e96 <d8f57049521948df5f50797141472fbbed3b0723; patch: 0

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

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Linux — Linux

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