{"id":"DEBIAN-CVE-2025-21876","details":"In the Linux kernel, the following vulnerability has been resolved:  iommu/vt-d: Fix suspicious RCU usage  Commit \u003cd74169ceb0d2\u003e (\"iommu/vt-d: Allocate DMAR fault interrupts locally\") moved the call to enable_drhd_fault_handling() to a code path that does not hold any lock while traversing the drhd list. Fix it by ensuring the dmar_global_lock lock is held when traversing the drhd list.  Without this fix, the following warning is triggered:  =============================  WARNING: suspicious RCU usage  6.14.0-rc3 #55 Not tainted  -----------------------------  drivers/iommu/intel/dmar.c:2046 RCU-list traversed in non-reader section!!                other info that might help us debug this:                rcu_scheduler_active = 1, debug_locks = 1  2 locks held by cpuhp/1/23:  #0: ffffffff84a67c50 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x87/0x2c0  #1: ffffffff84a6a380 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x87/0x2c0  stack backtrace:  CPU: 1 UID: 0 PID: 23 Comm: cpuhp/1 Not tainted 6.14.0-rc3 #55  Call Trace:   \u003cTASK\u003e   dump_stack_lvl+0xb7/0xd0   lockdep_rcu_suspicious+0x159/0x1f0   ? __pfx_enable_drhd_fault_handling+0x10/0x10   enable_drhd_fault_handling+0x151/0x180   cpuhp_invoke_callback+0x1df/0x990   cpuhp_thread_fun+0x1ea/0x2c0   smpboot_thread_fn+0x1f5/0x2e0   ? __pfx_smpboot_thread_fn+0x10/0x10   kthread+0x12a/0x2d0   ? __pfx_kthread+0x10/0x10   ret_from_fork+0x4a/0x60   ? __pfx_kthread+0x10/0x10   ret_from_fork_asm+0x1a/0x30   \u003c/TASK\u003e  Holding the lock in enable_drhd_fault_handling() triggers a lockdep splat about a possible deadlock between dmar_global_lock and cpu_hotplug_lock. This is avoided by not holding dmar_global_lock when calling iommu_device_register(), which initiates the device probe process.","modified":"2026-08-27T23:05:19.916682326Z","published":"2025-03-27T15:15:55.430Z","upstream":["CVE-2025-21876"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2025-21876"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.19-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2025-21876.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.19-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2025-21876.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}