{"id":"CVE-2024-40998","title":"ext4: fix uninitialized ratelimit_state->lock access in __ext4_fill_super()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix uninitialized ratelimit_state->lock access in __ext4_fill_super()\n\nIn the following concurrency we will access the uninitialized rs->lock:\n\next4_fill_super\n  …","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= efbed4dc5857f845d787e406ce85097d1ccc5c4f < 1e2df0ee0afd6d4b436a740f04f7a759e6531005","Linux >= efbed4dc5857f845d787e406ce85097d1ccc5c4f < 23afcd52af06880c6c913a0ad99022b8937b575c","Linux >= efbed4dc5857f845d787e406ce85097d1ccc5c4f < 645267906944a9aeec9d5c56ee24a9096a288798","Linux >= efbed4dc5857f845d787e406ce85097d1ccc5c4f < b4b4fda34e535756f9e774fb2d09c4537b7dfd1c","Linux 3.13"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2024-09-10T17:01:25.647023Z"},"published":"2024-07-12","updated":"2026-10-30","sourceUpdated":"2026-10-30T12:18:38.884Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2024-40998","references":[{"url":"https://git.kernel.org/stable/c/1e2df0ee0afd6d4b436a740f04f7a759e6531005"},{"url":"https://git.kernel.org/stable/c/23afcd52af06880c6c913a0ad99022b8937b575c"},{"url":"https://git.kernel.org/stable/c/645267906944a9aeec9d5c56ee24a9096a288798"},{"url":"https://git.kernel.org/stable/c/b4b4fda34e535756f9e774fb2d09c4537b7dfd1c"}],"tags":["cve.org"],"epss":0.00271,"epssPercentile":0.19611,"ingestedAt":"2026-11-03T12:44:28.823Z","slug":"CVE-2024-40998","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\next4: fix uninitialized ratelimit_state->lock access in __ext4_fill_super()\n\nIn the following concurrency we will access the uninitialized rs->lock:\n\next4_fill_super\n  ext4_register_sysfs\n   // sysfs registered msg_ratelimit_interval_ms\n                             // Other processes modify rs->interval to\n                             // non-zero via msg_ratelimit_interval_ms\n  ext4_orphan_cleanup\n    ext4_msg(sb, KERN_INFO, \"Errors on filesystem, \"\n      __ext4_msg\n        ___ratelimit(&(EXT4_SB(sb)->s_msg_ratelimit_state)\n          if (!rs->interval)  // do nothing if interval is 0\n            return 1;\n          raw_spin_trylock_irqsave(&rs->lock, flags)\n            raw_spin_trylock(lock)\n              _raw_spin_trylock\n                __raw_spin_trylock\n                  spin_acquire(&lock->dep_map, 0, 1, _RET_IP_)\n                    lock_acquire\n                      __lock_acquire\n                        register_lock_class\n                          assign_lock_key\n                            dump_stack();\n  ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);\n    raw_spin_lock_init(&rs->lock);\n    // init rs->lock here\n\nand get the following dump_stack:\n\n=========================================================\nINFO: trying to register non-static key.\nThe code is fine but needs lockdep annotation, or maybe\nyou didn't initialize this object before use?\nturning off the locking correctness validator.\nCPU: 12 PID: 753 Comm: mount Tainted: G E 6.7.0-rc6-next-20231222 #504\n[...]\nCall Trace:\n dump_stack_lvl+0xc5/0x170\n dump_stack+0x18/0x30\n register_lock_class+0x740/0x7c0\n __lock_acquire+0x69/0x13a0\n lock_acquire+0x120/0x450\n _raw_spin_trylock+0x98/0xd0\n ___ratelimit+0xf6/0x220\n __ext4_msg+0x7f/0x160 [ext4]\n ext4_orphan_cleanup+0x665/0x740 [ext4]\n __ext4_fill_super+0x21ea/0x2b10 [ext4]\n ext4_fill_super+0x14d/0x360 [ext4]\n[...]\n=========================================================\n\nNormally interval is 0 until s_msg_ratelimit_state is initialized, so\n___ratelimit() does nothing. But registering sysfs precedes initializing\nrs->lock, so it is possible to change rs->interval to a non-zero value\nvia the msg_ratelimit_interval_ms interface of sysfs while rs->lock is\nuninitialized, and then a call to ext4_msg triggers the problem by\naccessing an uninitialized rs->lock. Therefore register sysfs after all\ninitializations are complete to avoid such problems.\n\n## Affected\n\n- `Linux >= efbed4dc5857f845d787e406ce85097d1ccc5c4f < 1e2df0ee0afd6d4b436a740f04f7a759e6531005`\n- `Linux >= efbed4dc5857f845d787e406ce85097d1ccc5c4f < 23afcd52af06880c6c913a0ad99022b8937b575c`\n- `Linux >= efbed4dc5857f845d787e406ce85097d1ccc5c4f < 645267906944a9aeec9d5c56ee24a9096a288798`\n- `Linux >= efbed4dc5857f845d787e406ce85097d1ccc5c4f < b4b4fda34e535756f9e774fb2d09c4537b7dfd1c`\n- `Linux 3.13`\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":0.1,"exploitation":0,"ransomware":0},"changes":[]}