# CVE-2023-52982: linux: In the Linux kernel, the following vulnerability has been resolved: fscache: Use wait_on_bit() to wait for the freei... CVE-2023-52982 is fixed in 20 products on 1 platform, first by ALAS2023-2023-132, released March 11, 2023. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2023-52982 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0023 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Mar 11, 2023 ## Description In the Linux kernel, the following vulnerability has been resolved: fscache: Use wait_on_bit() to wait for the freeing of relinquished volume The freeing of relinquished volume will wake up the pending volume acquisition by using wake_up_bit(), however it is mismatched with wait_var_event() used in fscache_wait_on_volume_collision() and it will never wake up the waiter in the wait-queue because these two functions operate on different wait-queues. According to the implementation in fscache_wait_on_volume_collision(), if the wake-up of pending acquisition is delayed longer than 20 seconds (e.g., due to the delay of on-demand fd closing), the first wait_var_event_timeout() will timeout and the following wait_var_event() will hang forever as shown below: FS-Cache: Potential volume collision new=00000024 old=00000022 ...... INFO: task mount:1148 blocked for more than 122 seconds. Not tainted 6.1.0-rc6+ #1 task:mount state:D stack:0 pid:1148 ppid:1 Call Trace: __schedule+0x2f6/0xb80 schedule+0x67/0xe0 fscache_wait_on_volume_collision.cold+0x80/0x82 __fscache_acquire_volume+0x40d/0x4e0 erofs_fscache_register_volume+0x51/0xe0 [erofs] erofs_fscache_register_fs+0x19c/0x240 [erofs] erofs_fc_fill_super+0x746/0xaf0 [erofs] vfs_get_super+0x7d/0x100 get_tree_nodev+0x16/0x20 erofs_fc_get_tree+0x20/0x30 [erofs] vfs_get_tree+0x24/0xb0 path_mount+0x2fa/0xa90 do_mount+0x7c/0xa0 __x64_sys_mount+0x8b/0xe0 do_syscall_64+0x30/0x60 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Considering that wake_up_bit() is more selective, so fix it by using wait_on_bit() instead of wait_var_event() to wait for the freeing of relinquished volume. In addition because waitqueue_active() is used in wake_up_bit() and clear_bit() doesn't imply any memory barrier, use clear_and_wake_up_bit() to add the missing memory barrier between cursor->flags and waitqueue_active(). ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | bpftool-debuginfo amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel-debuginfo amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel-debuginfo-common-aarch64 amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel-debuginfo-common-x86_64 amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel-devel amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel-headers amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel-libbpf amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel-libbpf-devel amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel-libbpf-static amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel-livepatch-6.1.12-17.42 amzn 2023 | 1.0-0.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel-tools amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel-tools-debuginfo amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | kernel-tools-devel amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | linux Debian 12.15 (bookworm) | 6.1.11-1 | [DEBIAN-CVE-2023-52982](https://patchblox.com/security/data/fix/linux/debian-cve-2023-52982.md) | Mar 27, 2025 | | Linux | linux Debian 13.5 (trixie) | 6.1.11-1 | [DEBIAN-CVE-2023-52982](https://patchblox.com/security/data/fix/linux/debian-cve-2023-52982.md) | Mar 27, 2025 | | Linux | linux Debian 14 | 6.1.11-1 | [DEBIAN-CVE-2023-52982](https://patchblox.com/security/data/fix/linux/debian-cve-2023-52982.md) | Mar 27, 2025 | | Linux | perf amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | perf-debuginfo amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | python3-perf amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | | Linux | python3-perf-debuginfo amzn 2023 | 6.1.12-17.42.amzn2023 | [ALAS2023-2023-132](https://patchblox.com/security/data/fix/linux/alas2023-2023-132.md) | Mar 11, 2023 | --- Data as of 2026-11-09T01:18:40Z UTC. 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