CVE - CVE-2024-53054

CVE-ID
CVE-2024-53054	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
In the Linux kernel, the following vulnerability has been resolved: cgroup/bpf: use a dedicated workqueue for cgroup bpf destruction A hung_task problem shown below was found: INFO: task kworker/0:0:8 blocked for more than 327 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Workqueue: events cgroup_bpf_release Call Trace: <TASK> __schedule+0x5a2/0x2050 ? find_held_lock+0x33/0x100 ? wq_worker_sleeping+0x9e/0xe0 schedule+0x9f/0x180 schedule_preempt_disabled+0x25/0x50 __mutex_lock+0x512/0x740 ? cgroup_bpf_release+0x1e/0x4d0 ? cgroup_bpf_release+0xcf/0x4d0 ? process_scheduled_works+0x161/0x8a0 ? cgroup_bpf_release+0x1e/0x4d0 ? mutex_lock_nested+0x2b/0x40 ? __pfx_delay_tsc+0x10/0x10 mutex_lock_nested+0x2b/0x40 cgroup_bpf_release+0xcf/0x4d0 ? process_scheduled_works+0x161/0x8a0 ? trace_event_raw_event_workqueue_execute_start+0x64/0xd0 ? process_scheduled_works+0x161/0x8a0 process_scheduled_works+0x23a/0x8a0 worker_thread+0x231/0x5b0 ? __pfx_worker_thread+0x10/0x10 kthread+0x14d/0x1c0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x59/0x70 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1b/0x30 </TASK> This issue can be reproduced by the following pressuse test: 1. A large number of cpuset cgroups are deleted. 2. Set cpu on and off repeatly. 3. Set watchdog_thresh repeatly. The scripts can be obtained at LINK mentioned above the signature. The reason for this issue is cgroup_mutex and cpu_hotplug_lock are acquired in different tasks, which may lead to deadlock. It can lead to a deadlock through the following steps: 1. A large number of cpusets are deleted asynchronously, which puts a large number of cgroup_bpf_release works into system_wq. The max_active of system_wq is WQ_DFL_ACTIVE(256). Consequently, all active works are cgroup_bpf_release works, and many cgroup_bpf_release works will be put into inactive queue. As illustrated in the diagram, there are 256 (in the acvtive queue) + n (in the inactive queue) works. 2. Setting watchdog_thresh will hold cpu_hotplug_lock.read and put smp_call_on_cpu work into system_wq. However step 1 has already filled system_wq, 'sscs.work' is put into inactive queue. 'sscs.work' has to wait until the works that were put into the inacvtive queue earlier have executed (n cgroup_bpf_release), so it will be blocked for a while. 3. Cpu offline requires cpu_hotplug_lock.write, which is blocked by step 2. 4. Cpusets that were deleted at step 1 put cgroup_release works into cgroup_destroy_wq. They are competing to get cgroup_mutex all the time. When cgroup_metux is acqured by work at css_killed_work_fn, it will call cpuset_css_offline, which needs to acqure cpu_hotplug_lock.read. However, cpuset_css_offline will be blocked for step 3. 5. At this moment, there are 256 works in active queue that are cgroup_bpf_release, they are attempting to acquire cgroup_mutex, and as a result, all of them are blocked. Consequently, sscs.work can not be executed. Ultimately, this situation leads to four processes being blocked, forming a deadlock. system_wq(step1) WatchDog(step2) cpu offline(step3) cgroup_destroy_wq(step4) ... 2000+ cgroups deleted asyn 256 actives + n inactives __lockup_detector_reconfigure P(cpu_hotplug_lock.read) put sscs.work into system_wq 256 + n + 1(sscs.work) sscs.work wait to be executed warting sscs.work finish percpu_down_write P(cpu_hotplug_lock.write) ...blocking... css_killed_work_fn P(cgroup_mutex) cpuset_css_offline P(cpu_hotplug_lock.read) ...blocking... 256 cgroup_bpf_release mutex_lock(&cgroup_mutex); ..blocking... To fix the problem, place cgroup_bpf_release works on a dedicated workqueue which can break the loop and solve the problem. System wqs are for misc things which shouldn't create a large number of concurrent work items. If something is going to generate > ---truncated---
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/0d86cd70fc6a7ba18becb52ad8334d5ad3eca530 URL:https://git.kernel.org/stable/c/0d86cd70fc6a7ba18becb52ad8334d5ad3eca530 MISC:https://git.kernel.org/stable/c/117932eea99b729ee5d12783601a4f7f5fd58a23 URL:https://git.kernel.org/stable/c/117932eea99b729ee5d12783601a4f7f5fd58a23 MISC:https://git.kernel.org/stable/c/6dab3331523ba73db1345d19e6f586dcd5f6efb4 URL:https://git.kernel.org/stable/c/6dab3331523ba73db1345d19e6f586dcd5f6efb4 MISC:https://git.kernel.org/stable/c/71f14a9f5c7db72fdbc56e667d4ed42a1a760494 URL:https://git.kernel.org/stable/c/71f14a9f5c7db72fdbc56e667d4ed42a1a760494
Assigning CNA
kernel.org
Date Record Created
20241119	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20241119)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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