{"id":"CVE-2024-56565","title":"f2fs: fix to drop all discards after creating snapshot on lvm device","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to drop all discards after creating snapshot on lvm device\n\nPiergiorgio reported a bug in bugzilla as below:\n\n------------[ cut here ]------------\nWARNING: CP…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 35ec7d5748849762008e8ae9f8ad2766229d5794 < 0f3b00763dae90e94eed94a39d32d252d8750e9d","Linux >= 35ec7d5748849762008e8ae9f8ad2766229d5794 < ed24ab98242f8d22b66fbe0452c97751b5ea4e22","Linux >= 35ec7d5748849762008e8ae9f8ad2766229d5794 < 15136c3861a3341db261ebdbb6ae4ae1765635e2","Linux >= 35ec7d5748849762008e8ae9f8ad2766229d5794 < bc8aeb04fd80cb8cfae3058445c84410fd0beb5e","Linux 4.19"],"published":"2024-12-27","updated":"2026-10-30","sourceUpdated":"2026-10-30T12:20:18.174Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2024-56565","references":[{"url":"https://git.kernel.org/stable/c/0f3b00763dae90e94eed94a39d32d252d8750e9d"},{"url":"https://git.kernel.org/stable/c/ed24ab98242f8d22b66fbe0452c97751b5ea4e22"},{"url":"https://git.kernel.org/stable/c/15136c3861a3341db261ebdbb6ae4ae1765635e2"},{"url":"https://git.kernel.org/stable/c/bc8aeb04fd80cb8cfae3058445c84410fd0beb5e"}],"tags":["cve.org"],"epss":0.0022,"epssPercentile":0.12576,"ingestedAt":"2026-11-03T14:47:02.525Z","slug":"CVE-2024-56565","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to drop all discards after creating snapshot on lvm device\n\nPiergiorgio reported a bug in bugzilla as below:\n\n------------[ cut here ]------------\nWARNING: CPU: 2 PID: 969 at fs/f2fs/segment.c:1330\nRIP: 0010:__submit_discard_cmd+0x27d/0x400 [f2fs]\nCall Trace:\n __issue_discard_cmd+0x1ca/0x350 [f2fs]\n issue_discard_thread+0x191/0x480 [f2fs]\n kthread+0xcf/0x100\n ret_from_fork+0x31/0x50\n ret_from_fork_asm+0x1a/0x30\n\nw/ below testcase, it can reproduce this bug quickly:\n- pvcreate /dev/vdb\n- vgcreate myvg1 /dev/vdb\n- lvcreate -L 1024m -n mylv1 myvg1\n- mount /dev/myvg1/mylv1 /mnt/f2fs\n- dd if=/dev/zero of=/mnt/f2fs/file bs=1M count=20\n- sync\n- rm /mnt/f2fs/file\n- sync\n- lvcreate -L 1024m -s -n mylv1-snapshot /dev/myvg1/mylv1\n- umount /mnt/f2fs\n\nThe root cause is: it will update discard_max_bytes of mounted lvm\ndevice to zero after creating snapshot on this lvm device, then,\n__submit_discard_cmd() will pass parameter @nr_sects w/ zero value\nto __blkdev_issue_discard(), it returns a NULL bio pointer, result\nin panic.\n\nThis patch changes as below for fixing:\n1. Let's drop all remained discards in f2fs_unfreeze() if snapshot\nof lvm device is created.\n2. Checking discard_max_bytes before submitting discard during\n__submit_discard_cmd().\n\n## Affected\n\n- `Linux >= 35ec7d5748849762008e8ae9f8ad2766229d5794 < 0f3b00763dae90e94eed94a39d32d252d8750e9d`\n- `Linux >= 35ec7d5748849762008e8ae9f8ad2766229d5794 < ed24ab98242f8d22b66fbe0452c97751b5ea4e22`\n- `Linux >= 35ec7d5748849762008e8ae9f8ad2766229d5794 < 15136c3861a3341db261ebdbb6ae4ae1765635e2`\n- `Linux >= 35ec7d5748849762008e8ae9f8ad2766229d5794 < bc8aeb04fd80cb8cfae3058445c84410fd0beb5e`\n- `Linux 4.19`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}