CVE-2026-23217

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

riscv: trace: fix snapshot deadlock with sbi ecall

If sbi_ecall.c's functions are traceable,

echo "__sbi_ecall:snapshot" > /sys/kernel/tracing/set_ftrace_filter

may get the kernel into a deadlock.

(Functions in sbi_ecall.c are excluded from tracing if

CONFIG_RISCV_ALTERNATIVE_EARLY is set.)

__sbi_ecall triggers a snapshot of the ringbuffer. The snapshot code

raises an IPI interrupt, which results in another call to __sbi_ecall

and another snapshot...

All it takes to get into this endless loop is one initial __sbi_ecall.

On RISC-V systems without SSTC extension, the clock events in

timer-riscv.c issue periodic sbi ecalls, making the problem easy to

trigger.

Always exclude the sbi_ecall.c functions from tracing to fix the

potential deadlock.

sbi ecalls can easiliy be logged via trace events, excluding ecall

functions from function tracing is not a big limitation.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References