{"id":"CVE-2024-36478","summary":"null_blk: fix null-ptr-dereference while configuring 'power' and 'submit_queues'","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnull_blk: fix null-ptr-dereference while configuring 'power' and 'submit_queues'\n\nWriting 'power' and 'submit_queues' concurrently will trigger kernel\npanic:\n\nTest script:\n\nmodprobe null_blk nr_devices=0\nmkdir -p /sys/kernel/config/nullb/nullb0\nwhile true; do echo 1 \u003e submit_queues; echo 4 \u003e submit_queues; done &\nwhile true; do echo 1 \u003e power; echo 0 \u003e power; done\n\nTest result:\n\nBUG: kernel NULL pointer dereference, address: 0000000000000148\nOops: 0000 [#1] PREEMPT SMP\nRIP: 0010:__lock_acquire+0x41d/0x28f0\nCall Trace:\n \u003cTASK\u003e\n lock_acquire+0x121/0x450\n down_write+0x5f/0x1d0\n simple_recursive_removal+0x12f/0x5c0\n blk_mq_debugfs_unregister_hctxs+0x7c/0x100\n blk_mq_update_nr_hw_queues+0x4a3/0x720\n nullb_update_nr_hw_queues+0x71/0xf0 [null_blk]\n nullb_device_submit_queues_store+0x79/0xf0 [null_blk]\n configfs_write_iter+0x119/0x1e0\n vfs_write+0x326/0x730\n ksys_write+0x74/0x150\n\nThis is because del_gendisk() can concurrent with\nblk_mq_update_nr_hw_queues():\n\nnullb_device_power_store\tnullb_apply_submit_queues\n null_del_dev\n del_gendisk\n\t\t\t\t nullb_update_nr_hw_queues\n\t\t\t\t  if (!dev-\u003enullb)\n\t\t\t\t  // still set while gendisk is deleted\n\t\t\t\t   return 0\n\t\t\t\t  blk_mq_update_nr_hw_queues\n dev-\u003enullb = NULL\n\nFix this problem by resuing the global mutex to protect\nnullb_device_power_store() and nullb_update_nr_hw_queues() from configfs.","modified":"2026-04-02T12:10:16.561648Z","published":"2024-06-21T10:18:09.027Z","related":["SUSE-SU-2024:2372-1","SUSE-SU-2024:2394-1","SUSE-SU-2024:2571-1","SUSE-SU-2024:2896-1","SUSE-SU-2024:2939-1","SUSE-SU-2024:2973-1","SUSE-SU-2025:20008-1","SUSE-SU-2025:20028-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/36xxx/CVE-2024-36478.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1d4c8baef435c98e8d5aa7027dc5a9f70834ba16"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5d0495473ee4c1d041b5a917f10446a22c047f47"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a2db328b0839312c169eb42746ec46fc1ab53ed2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/aaadb755f2d684f715a6eb85cb7243aa0c67dfa9"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/36xxx/CVE-2024-36478.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-36478"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"45919fbfe1c487c17ea1d198534339a5e8abeae3"},{"fixed":"1d4c8baef435c98e8d5aa7027dc5a9f70834ba16"},{"fixed":"aaadb755f2d684f715a6eb85cb7243aa0c67dfa9"},{"fixed":"5d0495473ee4c1d041b5a917f10446a22c047f47"},{"fixed":"a2db328b0839312c169eb42746ec46fc1ab53ed2"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-36478.json"}}],"schema_version":"1.7.5"}