CVE-2026-23217

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 "_sbiecall:snapshot" > /sys/kernel/tracing/setftracefilter

may get the kernel into a deadlock.

(Functions in sbiecall.c are excluded from tracing if CONFIGRISCVALTERNATIVEEARLY is set.)

__sbi_ecall triggers a snapshot of the ringbuffer. The snapshot code raises an IPI interrupt, which results in another call to _sbiecall and another snapshot...

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