CVE-2026-23217: riscv: trace: fix snapshot deadlock with sbi ecall

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-02-18 · updated 2026-10-21
Weakness: CWE-667

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.

Affected products

Linux kernel: from 6.10.10 before 6.11; from 6.11.1 before 6.18.10; 6.11, 6.11-rc7, 6.19-rc1, 6.19-rc2, 6.19-rc3, 6.19-rc4 — fixed in 6.11, 6.18.10

How to fix

Upgrade to a fixed version: Linux kernel 6.11, 6.18.10. Check the vendor advisory for mitigations.

References

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