CVE-2025-39813

Description

In the Linux kernel, the following vulnerability has been resolved:ftrace: Fix potential warning in trace_printk_seq during ftrace_dumpWhen calling ftrace_dump_one() concurrently with reading trace_pipe,a WARN_ON_ONCE() in trace_printk_seq() can be triggered due to a racecondition.The issue occurs because:CPU0 (ftrace_dump) CPU1 (reader)echo z > /proc/sysrq-trigger!trace_empty(&iter)trace_iterator_reset(&iter) <- len = size = 0 cat /sys/kernel/tracing/trace_pipetrace_find_next_entry_inc(&iter) __find_next_entry ring_buffer_empty_cpu <- all empty return nulltrace_printk_seq(&iter.seq) WARN_ON_ONCE(s->seq.len >= s->seq.size)In the context between trace_empty() and trace_find_next_entry_inc()during ftrace_dump, the ring buffer data was consumed by other readers.This caused trace_find_next_entry_inc to return null, failing to populateiter.seq. At this point, due to the prior trace_iterator_reset, bothiter.seq.len and iter.seq.size were set to 0. Since they are equal,the WARN_ON_ONCE condition is triggered.Move the trace_printk_seq() into the if block that checks to make sure thereturn value of trace_find_next_entry_inc() is non-null inftrace_dump_one(), ensuring the iter.seq is properly populated beforesubsequent operations.

Risk Information

Associated Vulnerability

Patch Details

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234