{"id":"CVE-2026-98079","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: zstd: fix lost wakeup when waiting for a workspace\n\nA writer can sleep forever in zstd_get_workspace() even though a workspace\nis free","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: zstd: fix lost wakeup when waiting for a workspace\n\nA writer can sleep forever in zstd_get_workspace() even though a workspace\nis free.  When zstd_alloc_workspac…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 3f93aef535c8ea03e40cd8acf0753b3e6ed33e96 < d8f57049521948df5f50797141472fbbed3b0723","Linux >= 3f93aef535c8ea03e40cd8acf0753b3e6ed33e96 < 0de9f31d447ae71ab08c7850a321682f8d2907c3","Linux >= 3f93aef535c8ea03e40cd8acf0753b3e6ed33e96 < 2acb9f3d1cc8f65dc81ed55e238cbf8e5b60bff7","Linux 5.1"],"published":"2026-09-25","updated":"2026-09-25","sourceUpdated":"2026-09-25T11:17:37.307","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98079","references":[{"url":"https://git.kernel.org/stable/c/0de9f31d447ae71ab08c7850a321682f8d2907c3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2acb9f3d1cc8f65dc81ed55e238cbf8e5b60bff7","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d8f57049521948df5f50797141472fbbed3b0723","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-25T11:06:38.836Z","slug":"CVE-2026-98079","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: zstd: fix lost wakeup when waiting for a workspace\n\nA writer can sleep forever in zstd_get_workspace() even though a workspace\nis free.  When zstd_alloc_workspace() fails, the task is queued on\nzwsm->wait and schedules unconditionally, never re-testing the pool.\nzstd_put_workspace() publishes the workspace and then calls cond_wake_up(),\nwhich only wakes when a sleeper is already visible, so a workspace returned\nbetween the failed allocation and prepare_to_wait() wakes nobody.  The\nwindow is wide: zstd_alloc_workspace() goes through kvmalloc() and may\nenter reclaim.\n\nOnly a max level workspace triggers the wakeup and one is deliberately kept\nallocated as the fallback every waiter waits for, so once its wakeup is\nlost the writer stays in TASK_UNINTERRUPTIBLE until some other task happens\nto return one.  Re-check the pool after prepare_to_wait() has published the\nwaiter, and use the workspace if one turned up.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}