ghsa-cfrf-hx42-xr6f
Vulnerability from github
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.
{
"affected": [],
"aliases": [
"CVE-2025-39813"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-16T13:15:55Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nftrace: Fix potential warning in trace_printk_seq during ftrace_dump\n\nWhen calling ftrace_dump_one() concurrently with reading trace_pipe,\na WARN_ON_ONCE() in trace_printk_seq() can be triggered due to a race\ncondition.\n\nThe issue occurs because:\n\nCPU0 (ftrace_dump) CPU1 (reader)\necho z \u003e /proc/sysrq-trigger\n\n!trace_empty(\u0026iter)\ntrace_iterator_reset(\u0026iter) \u003c- len = size = 0\n cat /sys/kernel/tracing/trace_pipe\ntrace_find_next_entry_inc(\u0026iter)\n __find_next_entry\n ring_buffer_empty_cpu \u003c- all empty\n return NULL\n\ntrace_printk_seq(\u0026iter.seq)\n WARN_ON_ONCE(s-\u003eseq.len \u003e= s-\u003eseq.size)\n\nIn the context between trace_empty() and trace_find_next_entry_inc()\nduring ftrace_dump, the ring buffer data was consumed by other readers.\nThis caused trace_find_next_entry_inc to return NULL, failing to populate\n`iter.seq`. At this point, due to the prior trace_iterator_reset, both\n`iter.seq.len` and `iter.seq.size` were set to 0. Since they are equal,\nthe WARN_ON_ONCE condition is triggered.\n\nMove the trace_printk_seq() into the if block that checks to make sure the\nreturn value of trace_find_next_entry_inc() is non-NULL in\nftrace_dump_one(), ensuring the \u0027iter.seq\u0027 is properly populated before\nsubsequent operations.",
"id": "GHSA-cfrf-hx42-xr6f",
"modified": "2025-09-16T15:32:35Z",
"published": "2025-09-16T15:32:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39813"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/28c8fb7ae2ad27d81c8de3c4fe608c509f6a18aa"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4013aef2ced9b756a410f50d12df9ebe6a883e4a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5ab0ec206deb99eb3baf8f1d7602aeaa91dbcc85"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a6f0f8873cc30fd4543b09adf03f7f51d293f0e6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ced94e137e6cd5e79c65564841d3b7695d0f5fa3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e80ff23ba8bdb0f41a1afe2657078e4097d13a9a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f299353e7ccbcc5c2ed8993c48fbe7609cbe729a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fbd4cf7ee4db65ef36796769fe978e9eba6f0de4"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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