In the Linux kernel, the following vulnerability has been resolved:
s390: fix double free of GS and RI CBs on fork() failure
The pointers for guarded storage and runtime instrumentation control blocks are stored in the thread_struct of the associated task. These pointers are initially copied on fork() via arch_dup_task_struct() and then cleared via copy_thread() before fork() returns. If fork() happens to fail after the initial task dup and before copy_thread(), the newly allocated task and associated thread_struct memory are freed via free_task() -> arch_release_task_struct(). This results in a double free of the guarded storage and runtime info structs because the fields in the failed task still refer to memory associated with the source task.
This problem can manifest as a BUG_ON() in set_freepointer() (with CONFIG_SLAB_FREELIST_HARDENED enabled) or KASAN splat (if enabled) when running trinity syscall fuzz tests on s390x. To avoid this problem, clear the associated pointer fields in arch_dup_task_struct() immediately after the new task is copied. Note that the RI flag is still cleared in copy_thread() because it resides in thread stack memory and that is where stack info is copied.
CVSS Details
- CVSS 3.1 Base Score: 7.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | Upgrade linux | Jun 20, 2025 | Jun 20, 2025 |
| Dell Powerstore Dsa2025429 | — | Upgrade Dell PowerStoreOS to the latest version | Dec 3, 2025 | Dec 2, 2025 |
| Dell Powerstore Dsa2026039 | — | Upgrade Dell PowerStoreOS to the latest version | Jan 13, 2026 | Jan 6, 2026 |
| Redhat_linux | — | No solution exists | Jul 9, 2025 | Jun 18, 2025 |
| Ubuntu | — | Upgrade linux-gcp-fipsUpgrade linux-bluefieldUpgrade linux-hweUpgrade linux-raspi-5.4Upgrade linux-azure-4.15Upgrade linux-gcp-4.15Upgrade linux-realtimeUpgrade linux-gcpUpgrade linux-iotUpgrade linux-lowlatency-hwe-5.15Upgrade linux-azure-5.4Upgrade linux-awsUpgrade linux-aws-hweUpgrade linux-gcp-5.15Upgrade linuxUpgrade linux-nvidiaUpgrade linux-lowlatencyUpgrade linux-oracleUpgrade linux-ibm-5.4Upgrade linux-riscv-5.15Upgrade linux-ibmUpgrade linux-oracle-5.4Upgrade linux-aws-5.15Upgrade linux-intel-iotgUpgrade linux-intel-iotg-5.15Upgrade linux-hwe-5.4Upgrade linux-aws-fipsUpgrade linux-azureUpgrade linux-azure-5.15Upgrade linux-hwe-5.15Upgrade linux-oracle-5.15Upgrade linux-fipsUpgrade linux-gkeUpgrade linux-gkeopUpgrade linux-kvmUpgrade linux-aws-5.4Upgrade linux-azure-fipsUpgrade linux-raspiUpgrade linux-gcp-5.4 | Jun 26, 2025 | Jun 18, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | May 27, 2026 | Jun 18, 2025 |
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