GHSA-4JX3-FH7F-PXHW
Vulnerability from github – Published: 2026-09-04 18:31 – Updated: 2026-09-04 18:31In the Linux kernel, the following vulnerability has been resolved:
fuse: fix invalidate lock leak on setattr writeback failure
fuse_do_setattr() takes filemap_invalidate_lock() for a DAX truncate (fault_blocked = true) and releases it at the out:/error: labels. But when a writeback flush is also needed, a write_inode_now() failure returns directly and leaks the lock, so any later fault or truncate on the file stalls on the stale rwsem.
For example, truncate(2) on a setuid file reaches fuse_do_setattr() with both ATTR_SIZE and ATTR_MODE set:
truncate(2) └─ do_truncate() ├─ dentry_needs_remove_privs() # S_ISUID └─ notify_change() # KILL_SUID -> ATTR_MODE └─ fuse_setattr() # no killpriv: │ # ia_valid |= ATTR_MODE └─ fuse_do_setattr() ├─ filemap_invalidate_lock() # IS_DAX && is_truncate └─ write_inode_now() # is_wb && ATTR_MODE └─ if (err) # e.g. daemon -> -EIO return err # <- lock leaked
Fix this by adding an unlock label that releases the lock before returning the error, and use it for the fuse_dax_break_layouts() failure path as well.
{
"affected": [],
"aliases": [
"CVE-2026-80856"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-04T16:18:14Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfuse: fix invalidate lock leak on setattr writeback failure\n\nfuse_do_setattr() takes filemap_invalidate_lock() for a DAX truncate\n(fault_blocked = true) and releases it at the out:/error: labels. But\nwhen a writeback flush is also needed, a write_inode_now() failure\nreturns directly and leaks the lock, so any later fault or truncate on\nthe file stalls on the stale rwsem.\n\nFor example, truncate(2) on a setuid file reaches fuse_do_setattr()\nwith both ATTR_SIZE and ATTR_MODE set:\n\n truncate(2)\n \u2514\u2500 do_truncate()\n \u251c\u2500 dentry_needs_remove_privs() # S_ISUID\n \u2514\u2500 notify_change() # KILL_SUID -\u003e ATTR_MODE\n \u2514\u2500 fuse_setattr() # no killpriv:\n \u2502 # ia_valid |= ATTR_MODE\n \u2514\u2500 fuse_do_setattr()\n \u251c\u2500 filemap_invalidate_lock() # IS_DAX \u0026\u0026 is_truncate\n \u2514\u2500 write_inode_now() # is_wb \u0026\u0026 ATTR_MODE\n \u2514\u2500 if (err) # e.g. daemon -\u003e -EIO\n return err # \u003c- lock leaked\n\nFix this by adding an unlock label that releases the lock before\nreturning the error, and use it for the fuse_dax_break_layouts()\nfailure path as well.",
"id": "GHSA-4jx3-fh7f-pxhw",
"modified": "2026-09-04T18:31:29Z",
"published": "2026-09-04T18:31:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80856"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/03cfeeb135428fa83f0791d3f8f94d9298cae695"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1758730d9eaa3c06cf415c3446d9f6eed9ed3eed"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8f14906ce9103ab8f2f1ebda45935a0d61b9d763"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/92588d187ba4697a322e7aefe5d9e538a87d1cd2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9afeca0d569c9fc89d758fe7a9339d1e8afb1546"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dd278d954c0e96a9cbd3cc491e07b8267d25f8d5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e8457ebfd77a46e8d1210e8888ea914ad064558e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ea9fea370b8de4ffd72e0ef89550415c15637787"
}
],
"schema_version": "1.4.0",
"severity": []
}
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