{"id":"CVE-2026-74572","revision":"9ff990db2a0d4d5882aa918eb6ee9891","records":[{"revision":"9ff990db2a0d4d5882aa918eb6ee9891","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-74572","aliases":[],"title":"btrfs: zoned: fix deadlock between metadata writeback and transaction commit","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: zoned: fix deadlock between metadata writeback and transaction commit\n\nWhen writing out metadata extent buffers in a zoned filesystem,\nbtree_writepages() holds fs_info->zoned_meta_io_lock across the whole\nwriteback loop, including the call to btrfs_check_meta_write_pointer() ->\ncheck_bg_is_active().\n\nFor the tree-log block group, check_bg_is_active() may fail to activate\nthe zone and fall back to btrfs_zone_finish_one_bg() to free an active\nzone. That path waits for the running transaction to commit while still\nholding zoned_meta_io_lock, but the committer needs that same lock to\nwrite out the tree extents, so the two tasks deadlock:\n\n  Task A (kworker, metadata writeback)      Task B (fsstress, transaction commit)\n  ------------------------------------      -------------------------------------\n  wb_workfn()                               btrfs_commit_transaction(T)\n   btree_writepages()                        btrfs_write_and_wait_transaction()\n    btrfs_zoned_meta_io_lock()                btrfs_write_marked_extents()\n    btrfs_check_meta_write_pointer()           btree_writepages()\n     check_bg_is_active() [treelog_bg]          btrfs_zoned_meta_io_lock()\n      btrfs_zone_finish_one_bg()               <blocks on zoned_meta_io_lock,\n       btrfs_zone_finish()                      held by Task A>\n        do_zone_finish()\n         btrfs_inc_block_group_ro()\n          btrfs_wait_for_commit()\n           <blocks waiting for commit\n            of transaction T, done by\n            Task B>\n\nThe sibling branch in check_bg_is_active() already drops zoned_meta_io_lock\naround do_zone_finish() for this exact reason. Do the same in the tree-log\nbranch: release the lock around btrfs_zone_finish_one_bg() and re-acquire\nit afterwards. The lock only protects fs_info->active_{meta,system}_bg,\nwhich this branch does not touch, and ctx->zoned_bg keeps a reference to\nthe block group across the unlock, so nothing is lost while the lock\nis dropped.\n\nThis hang occasionally reproduces with fstests generic/475 on a zoned\nbtrfs filesystem.","state":0,"publishedAt":"2026-08-15T12:28:11.328+00:00","modifiedAt":"2026-10-16T19:05:56.826+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/btrfs/zoned.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"13bb483d32abb6f8ebd40141d87eb68f11cc2dd2\",\n                            \"lessThan\": \"18577e77c2c8adaadf1f7c6e9bcd1c0b14e5dcdd\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"13bb483d32abb6f8ebd40141d87eb68f11cc2dd2\",\n                            \"lessThan\": \"c3320873e0c04ce7b746fc8fe948f07bbbbdec33\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"13bb483d32abb6f8ebd40141d87eb68f11cc2dd2\",\n                            \"lessThan\": \"deddd28fd83c264ee2ff5cd6b34449a9f1be6112\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"13bb483d32abb6f8ebd40141d87eb68f11cc2dd2\",\n                            \"lessThan\": \"75859a7cd77cd2ddaddbcb963e3fcd34738953af\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"13bb483d32abb6f8ebd40141d87eb68f11cc2dd2\",\n                            \"lessThan\": \"1ebe51c29fa9755d5b2fea28727c051117907cf8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"fca3a1cd3ba47f1815e0c0fcdc9aafaf02ee0a75\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"6.5.5\",\n                            \"lessThan\": \"6.6\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/btrfs/zoned.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.6\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.6\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.151\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.103\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.44\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1.8\",\n                            \"lessThanOrEqual\": \"7.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/18577e77c2c8adaadf1f7c6e9bcd1c0b14e5dcdd","https://git.kernel.org/stable/c/c3320873e0c04ce7b746fc8fe948f07bbbbdec33","https://git.kernel.org/stable/c/deddd28fd83c264ee2ff5cd6b34449a9f1be6112","https://git.kernel.org/stable/c/75859a7cd77cd2ddaddbcb963e3fcd34738953af","https://git.kernel.org/stable/c/1ebe51c29fa9755d5b2fea28727c051117907cf8"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74572","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-74572","identifiers":["CVE-2026-74572"]},"retained":false,"historicalAffected":[]}],"coverage":[]}