CVE-2022-50177
Vulnerability Scoring
Status: Awaiting Analysis
Published on: 18 Jun 2025, 11:15 UTC
CVSS Release:
CVE-2022-50177: In the Linux kernel, the following vulnerability has been resolved: rcutorture: Fix ksoftirqd boosting timing and iteration The RCU priority boosting can fail in two situations: 1) If (nr_cpus= > maxcpus=), which means if the total number of CPUs is higher than those brought online at boot, then torture_onoff() may later bring up CPUs that weren't online on boot. Now since rcutorture initialization only boosts the ksoftirqds of the CPUs that have been set online on boot, the CPUs later set online by torture_onoff won't benefit from the boost, making RCU priority boosting fail. 2) The ksoftirqd kthreads are boosted after the creation of rcu_torture_boost() kthreads, which opens a window large enough for these rcu_torture_boost() kthreads to wait (despite running at FIFO priority) for ksoftirqds that are still running at SCHED_NORMAL priority. The issues can trigger for example with: ./kvm.sh --configs TREE01 --kconfig "CONFIG_RCU_BOOST=y" [ 34.968561] rcu-torture: !!! [ 34.968627] ------------[ cut here ]------------ [ 35.014054] WARNING: CPU: 4 PID: 114 at kernel/rcu/rcutorture.c:1979 rcu_torture_stats_print+0x5ad/0x610 [ 35.052043] Modules linked in: [ 35.069138] CPU: 4 PID: 114 Comm: rcu_torture_sta Not tainted 5.18.0-rc1 #1 [ 35.096424] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014 [ 35.154570] RIP: 0010:rcu_torture_stats_print+0x5ad/0x610 [ 35.198527] Code: 63 1b 02 00 74 02 0f 0b 48 83 3d 35 63 1b 02 00 74 02 0f 0b 48 83 3d 21 63 1b 02 00 74 02 0f 0b 48 83 3d 0d 63 1b 02 00 74 02 <0f> 0b 83 eb 01 0f 8e ba fc ff ff 0f 0b e9 b3 fc ff f82 [ 37.251049] RSP: 0000:ffffa92a0050bdf8 EFLAGS: 00010202 [ 37.277320] rcu: De-offloading 8 [ 37.290367] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000001 [ 37.290387] RDX: 0000000000000000 RSI: 00000000ffffbfff RDI: 00000000ffffffff [ 37.290398] RBP: 000000000000007b R08: 0000000000000000 R09: c0000000ffffbfff [ 37.290407] R10: 000000000000002a R11: ffffa92a0050bc18 R12: ffffa92a0050be20 [ 37.290417] R13: ffffa92a0050be78 R14: 0000000000000000 R15: 000000000001bea0 [ 37.290427] FS: 0000000000000000(0000) GS:ffff96045eb00000(0000) knlGS:0000000000000000 [ 37.290448] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 37.290460] CR2: 0000000000000000 CR3: 000000001dc0c000 CR4: 00000000000006e0 [ 37.290470] Call Trace: [ 37.295049] <TASK> [ 37.295065] ? preempt_count_add+0x63/0x90 [ 37.295095] ? _raw_spin_lock_irqsave+0x12/0x40 [ 37.295125] ? rcu_torture_stats_print+0x610/0x610 [ 37.295143] rcu_torture_stats+0x29/0x70 [ 37.295160] kthread+0xe3/0x110 [ 37.295176] ? kthread_complete_and_exit+0x20/0x20 [ 37.295193] ret_from_fork+0x22/0x30 [ 37.295218] </TASK> Fix this with boosting the ksoftirqds kthreads from the boosting hotplug callback itself and before the boosting kthreads are created.
The exploitability of CVE-2022-50177 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
No exploitability data is available for CVE-2022-50177.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2022-50177, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2022-50177, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
Unknown
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