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Vulnerability · Published May 21, 2024 · Assigned by Linux

CVE-2021-47254gfs2: Fix use-after-free in gfs2_glock_shrink_scan

High 7.8

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.2%top 84.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix use-after-free in gfs2_glock_shrink_scan The GLF_LRU flag is checked under lru_lock in gfs2_glock_remove_from_lru() to remove the glock from the lru list in __gfs2_glock_put(). On the shrink scan path, the same flag is cleared under lru_lock but because of cond_resched_lock(&lru_lock) in gfs2_dispose_glock_lru(), progress on the put side can be made without deleting the glock from the lru list. Keep GLF_LRU across the race window opened by cond_resched_lock(&lru_lock) to ensure correct behavior on both sides - clear GLF_LRU after list_del under lru_lock.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.10.46-1DEBIAN-CVE-2021-47254
Debian:13linux5.10.46-1DEBIAN-CVE-2021-47254
Debian:14linux5.10.46-1DEBIAN-CVE-2021-47254
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2021-47254
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2021-47254
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2021-47254

Affected products (as reported)

VendorProductVersions
Linux Linux 6948c6bc17d666663a84c124b3176039e64a58f4 – before 38ce329534500bf4ae71f81df6a37a406cf187b4b568ed385a18c0ddbe41862b69088b636550a04f – before 92869945cc5b78ee8a1ef90336fe070893e3458a762bb3528249604bc680a9df635e8995740176de – before 0364742decb0f02bc183404868b82896f7992595bac8520892812dada1ac93f27d96317470d24b1f – before 094bf5670e762afa243d2c41a5c4ab71c7447bf47881ef3f33bb80f459ea6020d1e021fc524a6348 – before 86fd5b27db743a0ce0cc245e3a34813b2aa6ec1d7881ef3f33bb80f459ea6020d1e021fc524a6348 – before a61156314b66456ab6a291ed5deba1ebd002ab3c7881ef3f33bb80f459ea6020d1e021fc524a6348 – before e87ef30fe73e7e10d2c85bdcc778dcec24dca5537881ef3f33bb80f459ea6020d1e021fc524a6348 – before 1ab19c5de4c537ec0d9b21020395a5b5a6c059b2
Linux Linux 5.2

References