CVE-2025-39813In the Linux kernel, the following vulnerability has been resolved: ftrace: Fix potential warning in trace_printk_seq during ftrace_dump When calling ftrace_dump_one() concurrently with reading trace…
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In the Linux kernel, the following vulnerability has been resolved: ftrace: Fix potential warning in trace_printk_seq during ftrace_dump When calling ftrace_dump_one() concurrently with reading trace_pipe, a WARN_ON_ONCE() in trace_printk_seq() can be triggered due to a race condition. 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_pipe trace_find_next_entry_inc(&iter) __find_next_entry ring_buffer_empty_cpu <- all empty return NULL trace_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 populate `iter.seq`. At this point, due to the prior trace_iterator_reset, both `iter.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 the return value of trace_find_next_entry_inc() is non-NULL in ftrace_dump_one(), ensuring the 'iter.seq' is properly populated before subsequent operations.
- CVSS
- 4.7 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-362
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Modified
- Record last updated
- Oct 19, 2026
- First seen by InfoSec Signals
- Oct 19, 2026
Affected products
linux linux_kernel linux:linux_kernel | from 2.6.28 before 5.4.298; from 5.5 before 5.10.242; from 5.11 before 5.15.191; from 5.16 before 6.1.150; from 6.2 before 6.6.104; from 6.7 before 6.12.45; from 6.13 before 6.16.5; 6.17; and 1 more ranges | NVD |
debian debian_linux debian:debian_linux | 11.0 | NVD |
References
- https://git.kernel.org/stable/c/28c8fb7ae2ad27d81c8de3c4fe608c509f6a18aapatch
- https://git.kernel.org/stable/c/4013aef2ced9b756a410f50d12df9ebe6a883e4apatch
- https://git.kernel.org/stable/c/5ab0ec206deb99eb3baf8f1d7602aeaa91dbcc85patch
- https://git.kernel.org/stable/c/a6f0f8873cc30fd4543b09adf03f7f51d293f0e6patch
- https://git.kernel.org/stable/c/ced94e137e6cd5e79c65564841d3b7695d0f5fa3patch
- https://git.kernel.org/stable/c/e80ff23ba8bdb0f41a1afe2657078e4097d13a9apatch
- https://git.kernel.org/stable/c/f299353e7ccbcc5c2ed8993c48fbe7609cbe729apatch
- https://git.kernel.org/stable/c/fbd4cf7ee4db65ef36796769fe978e9eba6f0de4patch
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.htmlthird-party-advisory
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlthird-party-advisory
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.