Linux RISCV Kernel: Trace Deadlock via __sbi_ecall Snapshot Loop
CVE-2026-23217 Published on February 18, 2026
riscv: trace: fix snapshot deadlock with sbi ecall
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.
Products Associated with CVE-2026-23217
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Affected Versions
Linux:- Version 1ff95eb2bebda50c4c5406caaf201e0fcb24cc8f and below b1f8285bc8e3508c1fde23b5205f1270215d4984 is affected.
- Version 1ff95eb2bebda50c4c5406caaf201e0fcb24cc8f and below b0d7f5f0c9f05f1b6d4ee7110f15bef9c11f9df0 is affected.
- Version 82f134ddd4f5da11c277bd1aa02e2a733179725a is affected.
- Version 6.11 is affected.
- Before 6.11 is unaffected.
- Version 6.18.10, <= 6.18.* is unaffected.
- Version 6.19, <= * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.