{"cve":"CVE-2024-39476","nvd":{"published":"2024-07-05T07:15:10.340","modified":"2026-06-17T07:41:59.833","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmd/raid5: fix deadlock that raid5d() wait for itself to clear MD_SB_CHANGE_PENDING\n\nXiao reported that lvm2 test lvconvert-raid-takeover.sh can hang with\nsmall possibility, the root cause is exactly the same as commit\nbed9e27baf52 (\"Revert \"md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d\"\")\n\nHowever, Dan reported another hang after that, and junxiao investigated\nthe problem and found out that this is caused by plugged bio can't issue\nfrom raid5d().\n\nCurrent implementation in raid5d() has a weird dependence:\n\n1) md_check_recovery() from raid5d() must hold 'reconfig_mutex' to clear\n   MD_SB_CHANGE_PENDING;\n2) raid5d() handles IO in a deadloop, until all IO are issued;\n3) IO from raid5d() must wait for MD_SB_CHANGE_PENDING to be cleared;\n\nThis behaviour is introduce before v2.6, and for consequence, if other\ncontext hold 'reconfig_mutex', and md_check_recovery() can't update\nsuper_block, then raid5d() will waste one cpu 100% by the deadloop, until\n'reconfig_mutex' is released.\n\nRefer to the implementation from raid1 and raid10, fix this problem by\nskipping issue IO if MD_SB_CHANGE_PENDING is still set after\nmd_check_recovery(), daemon thread will be woken up when 'reconfig_mutex'\nis released. Meanwhile, the hang problem will be fixed as well.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-667"],"references":["https://git.kernel.org/stable/c/098d54934814dd876963abfe751c3b1cf7fbe56a","https://git.kernel.org/stable/c/151f66bb618d1fd0eeb84acb61b4a9fa5d8bb0fa","https://git.kernel.org/stable/c/3f8d5e802d4cedd445f9a89be8c3fd2d0e99024b","https://git.kernel.org/stable/c/634ba3c97ec413cb10681c7b196db43ee461ecf4","https://git.kernel.org/stable/c/aa64464c8f4d2ab92f6d0b959a1e0767b829d787"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:52:00.836172422+00:00"},"epss":{"cve":"CVE-2024-39476","score":0.00178,"percentile":0.07408,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}