In the Linux kernel, the following vulnerability has been resolved:
tracing: Restructure trace_clock_global() to never block
It was reported that a fix to the ring buffer recursion detection would cause a hung machine when performing suspend / resume testing. The following backtrace was extracted from debugging that case:
Call Trace: trace_clock_global+0x91/0xa0 __rb_reserve_next+0x237/0x460 ring_buffer_lock_reserve+0x12a/0x3f0 trace_buffer_lock_reserve+0x10/0x50 __trace_graph_return+0x1f/0x80 trace_graph_return+0xb7/0xf0 ? trace_clock_global+0x91/0xa0 ftrace_return_to_handler+0x8b/0xf0 ? pv_hash+0xa0/0xa0 return_to_handler+0x15/0x30 ? ftrace_graph_caller+0xa0/0xa0 ? trace_clock_global+0x91/0xa0 ? __rb_reserve_next+0x237/0x460 ? ring_buffer_lock_reserve+0x12a/0x3f0 ? trace_event_buffer_lock_reserve+0x3c/0x120 ? trace_event_buffer_reserve+0x6b/0xc0 ? trace_event_raw_event_device_pm_callback_start+0x125/0x2d0 ? dpm_run_callback+0x3b/0xc0 ? pm_ops_is_empty+0x50/0x50 ? platform_get_irq_byname_optional+0x90/0x90 ? trace_device_pm_callback_start+0x82/0xd0 ? dpm_run_callback+0x49/0xc0
With the following RIP:
RIP: 0010:native_queued_spin_lock_slowpath+0x69/0x200
Since the fix to the recursion detection would allow a single recursion to happen while tracing, this lead to the trace_clock_global() taking a spin lock and then trying to take it again:
ring_buffer_lock_reserve() { trace_clock_global() { arch_spin_lock() { queued_spin_lock_slowpath() { /* lock taken */ (something else gets traced by function graph tracer) ring_buffer_lock_reserve() { trace_clock_global() { arch_spin_lock() { queued_spin_lock_slowpath() { /* DEAD LOCK! */
Tracing should *never* block, as it can lead to strange lockups like the above.
Restructure the trace_clock_global() code to instead of simply taking a lock to update the recorded "prev_time" simply use it, as two events happening on two different CPUs that calls this at the same time, really doesn't matter which one goes first. Use a trylock to grab the lock for updating the prev_time, and if it fails, simply try again the next time. If it failed to be taken, that means something else is already updating it.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=212761
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade kernel-develUpgrade bpftoolUpgrade kernel-cross-headersUpgrade kernel-rt-coreUpgrade kernelUpgrade kernel-debugUpgrade kernel-zfcpdump-develUpgrade kernel-tools-libs-develUpgrade kernel-rt-kvmUpgrade kernel-rt-debugUpgrade kernel-rt-modules-extraUpgrade kernel-rt-debug-coreUpgrade kernel-rt-develUpgrade kernel-headersUpgrade kernel-rt-debug-kvmUpgrade kernel-debug-develUpgrade python3-perfUpgrade kernel-zfcpdump-modulesUpgrade kernel-zfcpdumpUpgrade kernel-modulesUpgrade kernel-rtUpgrade kernel-abi-stablelistsUpgrade kernel-coreUpgrade kernel-rt-modulesUpgrade kernel-modules-extraUpgrade kernel-rt-debug-modules-extraUpgrade kernel-tools-libsUpgrade kernel-debug-modules-extraUpgrade kernel-debug-coreUpgrade kernel-rt-debug-modulesUpgrade kernel-docUpgrade kernel-zfcpdump-coreUpgrade kernel-zfcpdump-modules-extraUpgrade kernel-debug-modulesUpgrade kernel-rt-debug-develUpgrade perfUpgrade kernel-tools | Aug 12, 2024 | Feb 27, 2024 |
| Amazon Linux Ami 2 | — | Upgrade kernel-debuginfo-common-x86_64Upgrade kernel-tools-debuginfoUpgrade kernel-develUpgrade bpftoolUpgrade kernel-toolsUpgrade bpftool-debuginfoUpgrade kernelUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-debuginfoUpgrade kernel-headersUpgrade python-perf-debuginfoUpgrade perfUpgrade python-perfUpgrade kernel-livepatch-4.14.238-182.421Upgrade perf-debuginfoUpgrade kernel-tools-devel | Apr 25, 2024 | Feb 27, 2024 |
| Debian | — | Upgrade linux | Jul 30, 2024 | Feb 27, 2024 |
| Huawei Euleros 2_0_sp8 | — | Upgrade python-perfUpgrade kernel-develUpgrade kernel-tools-libsUpgrade kernel-headersUpgrade kernelUpgrade python3-perfUpgrade perfUpgrade bpftoolUpgrade kernel-tools | Jul 23, 2024 | Feb 27, 2024 |
| Huawei Euleros 2_0_sp9 | — | Upgrade kernelUpgrade python3-perfUpgrade kernel-toolsUpgrade kernel-tools-libs | Jul 17, 2024 | Feb 27, 2024 |
| Oracle_linux | — | Upgrade kernel-uekUpgrade kernel | Aug 16, 2024 | Feb 27, 2024 |
| Redhat_linux | — | No solution existsUpgrade kernel-rtUpgrade kernel | Aug 12, 2024 | Feb 27, 2024 |
| Rocky_linux | — | Upgrade kernel-rt-debug-kvmUpgrade kernel-modulesUpgrade kernel-rt-debug-modulesUpgrade kernel-rt-coreUpgrade kernelUpgrade kernel-coreUpgrade kernel-develUpgrade kernel-rt-debug-develUpgrade python3-perfUpgrade kernel-cross-headersUpgrade kernel-rt-debug-coreUpgrade kernel-headersUpgrade kernel-debugUpgrade kernel-debuginfoUpgrade kernel-modules-extraUpgrade kernel-tools-debuginfoUpgrade kernel-rt-debugUpgrade kernel-tools-libsUpgrade kernel-debug-modulesUpgrade kernel-rt-modules-extraUpgrade kernel-debug-coreUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-rt-debug-debuginfoUpgrade kernel-debug-develUpgrade kernel-rt-debuginfo-common-x86_64Upgrade perfUpgrade kernel-rt-debuginfoUpgrade kernel-debug-modules-extraUpgrade kernel-tools-libs-develUpgrade kernel-debug-debuginfoUpgrade kernel-rt-modulesUpgrade python3-perf-debuginfoUpgrade perf-debuginfoUpgrade kernel-rt-develUpgrade bpftoolUpgrade kernel-toolsUpgrade bpftool-debuginfoUpgrade kernel-rt-kvmUpgrade kernel-rt-debug-modules-extraUpgrade kernel-rt | Aug 22, 2024 | Feb 27, 2024 |
| Suse | — | Upgrade kernel-default-develUpgrade kernel-azureUpgrade kernel-default-baseUpgrade kernel-develUpgrade kernel-source-azureUpgrade kernel-obs-buildUpgrade reiserfs-kmp-defaultUpgrade kernel-64kb-develUpgrade kernel-preemptUpgrade kernel-sourceUpgrade kernel-64kbUpgrade kernel-preempt-develUpgrade kernel-azure-baseUpgrade kernel-default-extraUpgrade kernel-azure-develUpgrade kernel-zfcpdumpUpgrade kernel-docsUpgrade kernel-default-manUpgrade kernel-syms-azureUpgrade kernel-macrosUpgrade kernel-defaultUpgrade kernel-devel-azureUpgrade kernel-syms | Aug 9, 2024 | Feb 27, 2024 |
| Ubuntu | — | Upgrade linux-image-generic-lts-xenialUpgrade linux-image-genericUpgrade linux-image-lowlatencyUpgrade linux-image-4.4.0-1131-awsUpgrade linux-image-4.4.0-1169-awsUpgrade linux-image-4.4.0-254-genericUpgrade linux-image-kvmUpgrade linux-image-virtualUpgrade linux-image-4.4.0-254-lowlatencyUpgrade linux-image-lowlatency-lts-xenialUpgrade linux-image-awsUpgrade linux-image-4.4.0-1132-kvmUpgrade linux-image-virtual-lts-xenial | May 20, 2024 | Feb 27, 2024 |
Prioritise with Active Threat Intelligence
With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.
Explore Intelligence Hub