CVE-2024-50095: RDMA/mad: Improve handling of timed out WRs of mad agent
First published: Tue Nov 05 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: RDMA/mad: Improve handling of timed out WRs of mad agent Current timeout handler of mad agent acquires/releases mad_agent_priv lock for every timed out WRs. This causes heavy locking contention when higher no. of WRs are to be handled inside timeout handler. This leads to softlockup with below trace in some use cases where rdma-cm path is used to establish connection between peer nodes Trace: ----- BUG: soft lockup - CPU#4 stuck for 26s! [kworker/u128:3:19767] CPU: 4 PID: 19767 Comm: kworker/u128:3 Kdump: loaded Tainted: G OE ------- --- 5.14.0-427.13.1.el9_4.x86_64 #1 Hardware name: Dell Inc. PowerEdge R740/01YM03, BIOS 2.4.8 11/26/2019 Workqueue: ib_mad1 timeout_sends [ib_core] RIP: 0010:__do_softirq+0x78/0x2ac RSP: 0018:ffffb253449e4f98 EFLAGS: 00000246 RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 000000000000001f RDX: 000000000000001d RSI: 000000003d1879ab RDI: fff363b66fd3a86b RBP: ffffb253604cbcd8 R08: 0000009065635f3b R09: 0000000000000000 R10: 0000000000000040 R11: ffffb253449e4ff8 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000040 FS: 0000000000000000(0000) GS:ffff8caa1fc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd9ec9db900 CR3: 0000000891934006 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <IRQ> ? show_trace_log_lvl+0x1c4/0x2df ? show_trace_log_lvl+0x1c4/0x2df ? __irq_exit_rcu+0xa1/0xc0 ? watchdog_timer_fn+0x1b2/0x210 ? __pfx_watchdog_timer_fn+0x10/0x10 ? __hrtimer_run_queues+0x127/0x2c0 ? hrtimer_interrupt+0xfc/0x210 ? __sysvec_apic_timer_interrupt+0x5c/0x110 ? sysvec_apic_timer_interrupt+0x37/0x90 ? asm_sysvec_apic_timer_interrupt+0x16/0x20 ? __do_softirq+0x78/0x2ac ? __do_softirq+0x60/0x2ac __irq_exit_rcu+0xa1/0xc0 sysvec_call_function_single+0x72/0x90 </IRQ> <TASK> asm_sysvec_call_function_single+0x16/0x20 RIP: 0010:_raw_spin_unlock_irq+0x14/0x30 RSP: 0018:ffffb253604cbd88 EFLAGS: 00000247 RAX: 000000000001960d RBX: 0000000000000002 RCX: ffff8cad2a064800 RDX: 000000008020001b RSI: 0000000000000001 RDI: ffff8cad5d39f66c RBP: ffff8cad5d39f600 R08: 0000000000000001 R09: 0000000000000000 R10: ffff8caa443e0c00 R11: ffffb253604cbcd8 R12: ffff8cacb8682538 R13: 0000000000000005 R14: ffffb253604cbd90 R15: ffff8cad5d39f66c cm_process_send_error+0x122/0x1d0 [ib_cm] timeout_sends+0x1dd/0x270 [ib_core] process_one_work+0x1e2/0x3b0 ? __pfx_worker_thread+0x10/0x10 worker_thread+0x50/0x3a0 ? __pfx_worker_thread+0x10/0x10 kthread+0xdd/0x100 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x29/0x50 </TASK> Simplified timeout handler by creating local list of timed out WRs and invoke send handler post creating the list. The new method acquires/ releases lock once to fetch the list and hence helps to reduce locking contetiong when processing higher no. of WRs
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | <5.10.227 | |
| Linux Kernel | >=5.11<5.15.168 | |
| Linux Kernel | >=5.16<6.1.113 | |
| Linux Kernel | >=6.2<6.6.57 | |
| Linux Kernel | >=6.7<6.11.4 | |
| debian/linux | <=5.10.223-1<=5.10.226-1 | 6.1.123-1 6.1.128-1 6.12.12-1 6.12.15-1 |
| debian/linux-6.1 | 6.1.119-1~deb11u1 |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
- https://git.kernel.org/stable/c/2a777679b8ccd09a9a65ea0716ef10365179caac
- https://git.kernel.org/stable/c/3e799fa463508abe7a738ce5d0f62a8dfd05262a
- https://git.kernel.org/stable/c/7022a517bf1ca37ef5a474365bcc5eafd345a13a
- https://git.kernel.org/stable/c/713adaf0ecfc49405f6e5d9e409d984f628de818
- https://git.kernel.org/stable/c/a195a42dd25ca4f12489687065d00be64939409f
- https://git.kernel.org/stable/c/e80eadb3604a92d2d086e956b8b2692b699d4d0a
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-50095
- https://nvd.nist.gov/vuln/detail/CVE-2024-50095
- https://launchpad.net/bugs/cve/CVE-2024-50095
- https://security-tracker.debian.org/tracker/CVE-2024-50095
- https://ubuntu.com/security/CVE-2024-50095
- https://git.kernel.org/linus/2a777679b8ccd09a9a65ea0716ef10365179caac
Frequently Asked Questions
What is the severity of CVE-2024-50095?
CVE-2024-50095 has a medium severity rating due to potential locking contention affecting performance.
How do I fix CVE-2024-50095?
To fix CVE-2024-50095, upgrade to the recommended kernel versions 6.1.123-1, 6.1.119-1, 6.12.10-1, or 6.12.11-1 from Debian.
Which systems are affected by CVE-2024-50095?
CVE-2024-50095 affects multiple versions of the Linux kernel, particularly those prior to 5.10.227 and between 5.11 and 5.15.168.
What components of the Linux kernel are impacted by CVE-2024-50095?
CVE-2024-50095 specifically impacts the RDMA/mad component of the Linux kernel.
Is CVE-2024-50095 exploitable remotely?
CVE-2024-50095 does not appear to be remotely exploitable, but it may degrade performance under heavy load.
- agent/title
- agent/first-publish-date
- agent/type
- agent/remedy
- agent/severity
- agent/author
- collector/mitre-cve
- source/MITRE
- agent/last-modified-date
- agent/trending
- agent/references
- collector/usn-cve
- source/Ubuntu
- collector/nvd-cve
- source/NVD
- agent/software-canonical-lookup
- agent/software-canonical-lookup-request
- collector/nvd-api
- collector/launchpad-cve
- source/Launchpad
- collector/security-tracker-debian
- source/Debian
- agent/source
- agent/softwarecombine
- agent/tags
- agent/description
- agent/event
- vendor/linux
- canonical/linux kernel
- version/linux kernel/5.11
- version/linux kernel/5.16
- version/linux kernel/6.2
- version/linux kernel/6.7
- package-manager/debian