CVE-2026-97919tracing: Take the reference before publishing the named histogram trigger

Official description

In the Linux kernel, the following vulnerability has been resolved: tracing: Take the reference before publishing the named histogram trigger event_hist_trigger_named_init() puts the trigger on the global named_triggers list and only then takes the reference on the trigger it shares its histogram with: data->ref++; save_named_trigger(data->named_data->name, data); ret = event_hist_trigger_init(data->named_data); if (ret < 0) { kfree(data->cmd_ops); data->cmd_ops = &trigger_hist_cmd; } return ret; event_hist_trigger_init() fails when alloc_hist_pad() cannot allocate, and nothing takes the trigger back off the list on the way out. event_hist_trigger_parse() frees it, and the next lookup by name reads the freed object: BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0 Read of size 8 at addr ffff888009346860 by task init/1 find_named_trigger+0xac/0xc0 hist_register_trigger+0xc1/0xa00 event_hist_trigger_parse+0x3146/0x6af0 event_trigger_write+0xce/0x160 Freed by task 67: kfree+0x154/0x420 trigger_kthread_fn+0xfd/0x160 Do the reference first and publish once it has succeeded, so that nothing which can fail runs after the trigger becomes findable.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/e5c5dad169fb569161d3eed6c3f6a59e65db1830
• https://git.kernel.org/stable/c/b6fb2f5370a9a6aec325ab2db1ca3d1a881499b8
• https://git.kernel.org/stable/c/2ffaade3611bd9501bc0b9d5d19fc75bfee7a16b
• https://git.kernel.org/stable/c/91c15cdda6033e2439f5975b938754152f3d6e38
• https://git.kernel.org/stable/c/0fe23b8eaba0d3372c66b7b31204408da0715edc