Cloudanix VulnDB

CVE-2023-53655

Medium · 5.5

CVSS

5.5

EPSS

0.2%

Published

Oct 7, 2025

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Track

A bug in the Linux kernel can make the whole system crash when someone tries to use certain debugging tools on machines set up for low-power operation.

Exploitation
Local Privilege
Attacker needs
Low Privilege
Complexity
Low
Impact
Denial Of Service
Component
OS kernel
Class
Memory Corruption
Remediation
Patch
Effort
Low
Patch risk
Low

What it actually does

Kprobe registration on __rcu_irq_enter_check_tick() under CONFIG_NO_HZ_FULL triggers recursive entry/exit handling that exhausts the kernel stack, resulting in panic.

Why it matters to the business

Local debugging or tracing activity on affected Linux systems can cause immediate kernel crashes and loss of service availability.

How an attack unfolds

An attacker with shell access boots a kernel with nohz_full, registers a kprobe via tracefs on the target function, enables the probe, and triggers IRQ/NMI paths that recurse until stack overflow occurs.

How to fix it

Apply the upstream fix that marks __rcu_irq_enter_check_tick() with NOKPROBE_SYMBOL() and update to a kernel containing the blacklist change.

How to confirm the fix worked

Confirm the symbol is present in the kprobes blacklist after boot and verify that registering a probe on the function is rejected by the kernel.

Typical attack path

  1. Boot kernel with nohz_full= parameter
  2. Navigate to /sys/kernel/tracing/
  3. Register kprobe on __rcu_irq_enter_check_tick via kprobe_events
  4. Enable kprobe events
  5. Perform actions that invoke IRQ/NMI entry paths to trigger overflow

How to detect it

Review kernel crash logs for stack overflow during el1_dbg or __rcu_irq_enter_check_tick calls and inspect tracefs kprobe_events for probes on that function.

What your security team should do

  • Prioritize kernel updates containing the NOKPROBE_SYMBOL fix for systems using nohz_full
  • Restrict unprivileged access to tracefs and kprobe_events
  • Monitor for kernel panics referencing __rcu_irq_enter_check_tick in crash dumps

The record

In the Linux kernel, the following vulnerability has been resolved: rcu: Avoid stack overflow due to __rcu_irq_enter_check_tick() being kprobe-ed Registering a kprobe on __rcu_irq_enter_check_tick() can cause kernel stack overflow as shown below. This issue can be reproduced by enabling CONFIG_NO_HZ_FULL and booting the kernel with argument "nohz_full=", and then giving the following commands at the shell prompt: # cd /sys/kernel/tracing/ # echo 'p:mp1 __rcu_irq_enter_check_tick' >> kprobe_events # echo 1 > events/kprobes/enable This commit therefore adds __rcu_irq_enter_check_tick() to the kprobes blacklist using NOKPROBE_SYMBOL(). Insufficient stack space to handle exception! ESR: 0x00000000f2000004 -- BRK (AArch64) FAR: 0x0000ffffccf3e510 Task stack: [0xffff80000ad30000..0xffff80000ad38000] IRQ stack: [0xffff800008050000..0xffff800008058000] Overflow stack: [0xffff089c36f9f310..0xffff089c36fa0310] CPU: 5 PID: 190 Comm: bash Not tainted 6.2.0-rc2-00320-g1f5abbd77e2c #19 Hardware name: linux,dummy-virt (DT) pstate: 400003c5 (nZcv DAIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __rcu_irq_enter_check_tick+0x0/0x1b8 lr : ct_nmi_enter+0x11c/0x138 sp : ffff80000ad30080 x29: ffff80000ad30080 x28: ffff089c82e20000 x27: 0000000000000000 x26: 0000000000000000 x25: ffff089c02a8d100 x24: 0000000000000000 x23: 00000000400003c5 x22: 0000ffffccf3e510 x21: ffff089c36fae148 x20: ffff80000ad30120 x19: ffffa8da8fcce148 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: ffffa8da8e44ea6c x14: ffffa8da8e44e968 x13: ffffa8da8e03136c x12: 1fffe113804d6809 x11: ffff6113804d6809 x10: 0000000000000a60 x9 : dfff800000000000 x8 : ffff089c026b404f x7 : 00009eec7fb297f7 x6 : 0000000000000001 x5 : ffff80000ad30120 x4 : dfff800000000000 x3 : ffffa8da8e3016f4 x2 : 0000000000000003 x1 : 0000000000000000 x0 : 0000000000000000 Kernel panic - not syncing: kernel stack overflow CPU: 5 PID: 190 Comm: bash Not tainted 6.2.0-rc2-00320-g1f5abbd77e2c #19 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0xf8/0x108 show_stack+0x20/0x30 dump_stack_lvl+0x68/0x84 dump_stack+0x1c/0x38 panic+0x214/0x404 add_taint+0x0/0xf8 panic_bad_stack+0x144/0x160 handle_bad_stack+0x38/0x58 __bad_stack+0x78/0x7c __rcu_irq_enter_check_tick+0x0/0x1b8 arm64_enter_el1_dbg.isra.0+0x14/0x20 el1_dbg+0x2c/0x90 el1h_64_sync_handler+0xcc/0xe8 el1h_64_sync+0x64/0x68 __rcu_irq_enter_check_tick+0x0/0x1b8 arm64_enter_el1_dbg.isra.0+0x14/0x20 el1_dbg+0x2c/0x90 el1h_64_sync_handler+0xcc/0xe8 el1h_64_sync+0x64/0x68 __rcu_irq_enter_check_tick+0x0/0x1b8 arm64_enter_el1_dbg.isra.0+0x14/0x20 el1_dbg+0x2c/0x90 el1h_64_sync_handler+0xcc/0xe8 el1h_64_sync+0x64/0x68 __rcu_irq_enter_check_tick+0x0/0x1b8 [...] el1_dbg+0x2c/0x90 el1h_64_sync_handler+0xcc/0xe8 el1h_64_sync+0x64/0x68 __rcu_irq_enter_check_tick+0x0/0x1b8 arm64_enter_el1_dbg.isra.0+0x14/0x20 el1_dbg+0x2c/0x90 el1h_64_sync_handler+0xcc/0xe8 el1h_64_sync+0x64/0x68 __rcu_irq_enter_check_tick+0x0/0x1b8 arm64_enter_el1_dbg.isra.0+0x14/0x20 el1_dbg+0x2c/0x90 el1h_64_sync_handler+0xcc/0xe8 el1h_64_sync+0x64/0x68 __rcu_irq_enter_check_tick+0x0/0x1b8 el1_interrupt+0x28/0x60 el1h_64_irq_handler+0x18/0x28 el1h_64_irq+0x64/0x68 __ftrace_set_clr_event_nolock+0x98/0x198 __ftrace_set_clr_event+0x58/0x80 system_enable_write+0x144/0x178 vfs_write+0x174/0x738 ksys_write+0xd0/0x188 __arm64_sys_write+0x4c/0x60 invoke_syscall+0x64/0x180 el0_svc_common.constprop.0+0x84/0x160 do_el0_svc+0x48/0xe8 el0_svc+0x34/0xd0 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x190/0x194 SMP: stopping secondary CPUs Kernel Offset: 0x28da86000000 from 0xffff800008000000 PHYS_OFFSET: 0xfffff76600000000 CPU features: 0x00000,01a00100,0000421b Memory Limit: none

Affected packages

Ecosystem Package Introduced Fixed
Linux Kernel 5.8.0 5.10.180

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