# CVE-2025-39831: linux: In the Linux kernel, the following vulnerability has been resolved: fbnic: Move phylink resume out of service_task a... CVE-2025-39831 is fixed in 13 products on 1 platform, first by DEBIAN-CVE-2025-39831, released September 16, 2025. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2025-39831 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0015 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 16, 2025 ## Description In the Linux kernel, the following vulnerability has been resolved: fbnic: Move phylink resume out of service_task and into open/close The fbnic driver was presenting with the following locking assert coming out of a PM resume: [ 42.208116][ T164] RTNL: assertion failed at drivers/net/phy/phylink.c (2611) [ 42.208492][ T164] WARNING: CPU: 1 PID: 164 at drivers/net/phy/phylink.c:2611 phylink_resume+0x190/0x1e0 [ 42.208872][ T164] Modules linked in: [ 42.209140][ T164] CPU: 1 UID: 0 PID: 164 Comm: bash Not tainted 6.17.0-rc2-virtme #134 PREEMPT(full) [ 42.209496][ T164] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-5.fc42 04/01/2014 [ 42.209861][ T164] RIP: 0010:phylink_resume+0x190/0x1e0 [ 42.210057][ T164] Code: 83 e5 01 0f 85 b0 fe ff ff c6 05 1c cd 3e 02 01 90 ba 33 0a 00 00 48 c7 c6 20 3a 1d a5 48 c7 c7 e0 3e 1d a5 e8 21 b8 90 fe 90 <0f> 0b 90 90 e9 86 fe ff ff e8 42 ea 1f ff e9 e2 fe ff ff 48 89 ef [ 42.210708][ T164] RSP: 0018:ffffc90000affbd8 EFLAGS: 00010296 [ 42.210983][ T164] RAX: 0000000000000000 RBX: ffff8880078d8400 RCX: 0000000000000000 [ 42.211235][ T164] RDX: 0000000000000000 RSI: 1ffffffff4f10938 RDI: 0000000000000001 [ 42.211466][ T164] RBP: 0000000000000000 R08: ffffffffa2ae79ea R09: fffffbfff4b3eb84 [ 42.211707][ T164] R10: 0000000000000003 R11: 0000000000000000 R12: ffff888007ad8000 [ 42.211997][ T164] R13: 0000000000000002 R14: ffff888006a18800 R15: ffffffffa34c59e0 [ 42.212234][ T164] FS: 00007f0dc8e39740(0000) GS:ffff88808f51f000(0000) knlGS:0000000000000000 [ 42.212505][ T164] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 42.212704][ T164] CR2: 00007f0dc8e9fe10 CR3: 000000000b56d003 CR4: 0000000000772ef0 [ 42.213227][ T164] PKRU: 55555554 [ 42.213366][ T164] Call Trace: [ 42.213483][ T164] [ 42.213565][ T164] __fbnic_pm_attach.isra.0+0x8e/0xa0 [ 42.213725][ T164] pci_reset_function+0x116/0x1d0 [ 42.213895][ T164] reset_store+0xa0/0x100 [ 42.214025][ T164] ? pci_dev_reset_attr_is_visible+0x50/0x50 [ 42.214221][ T164] ? sysfs_file_kobj+0xc1/0x1e0 [ 42.214374][ T164] ? sysfs_kf_write+0x65/0x160 [ 42.214526][ T164] kernfs_fop_write_iter+0x2f8/0x4c0 [ 42.214677][ T164] ? kernfs_vma_page_mkwrite+0x1f0/0x1f0 [ 42.214836][ T164] new_sync_write+0x308/0x6f0 [ 42.214987][ T164] ? __lock_acquire+0x34c/0x740 [ 42.215135][ T164] ? new_sync_read+0x6f0/0x6f0 [ 42.215288][ T164] ? lock_acquire.part.0+0xbc/0x260 [ 42.215440][ T164] ? ksys_write+0xff/0x200 [ 42.215590][ T164] ? perf_trace_sched_switch+0x6d0/0x6d0 [ 42.215742][ T164] vfs_write+0x65e/0xbb0 [ 42.215876][ T164] ksys_write+0xff/0x200 [ 42.215994][ T164] ? __ia32_sys_read+0xc0/0xc0 [ 42.216141][ T164] ? do_user_addr_fault+0x269/0x9f0 [ 42.216292][ T164] ? rcu_is_watching+0x15/0xd0 [ 42.216442][ T164] do_syscall_64+0xbb/0x360 [ 42.216591][ T164] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 42.216784][ T164] RIP: 0033:0x7f0dc8ea9986 A bit of digging showed that we were invoking the phylink_resume as a part of the fbnic_up path when we were enabling the service task while not holding the RTNL lock. We should be enabling this sooner as a part of the ndo_open path and then just letting the service task come online later. This will help to enforce the correct locking and brings the phylink interface online at the same time as the network interface, instead of at a later time. I tested this on QEMU to verify this was working by putting the system to sleep using "echo mem > /sys/power/state" to put the system to sleep in the guest and then using the command "system_wakeup" in the QEMU monitor. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.8.1.160000.2.5 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.8.1.160000.2.5 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.8.1 | [OPENSUSE-SU-2025:20172-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2025-20172-1.md) | Dec 19, 2025 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.8.1 | [SUSE-SU-2026:20015-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20015-1.md) | Dec 19, 2025 | | Linux | linux Debian 13.5 (trixie) | 6.12.48-1 | [DEBIAN-CVE-2025-39831](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39831.md) | Sep 16, 2025 | | Linux | linux Debian 14 | 6.16.5-1 | [DEBIAN-CVE-2025-39831](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39831.md) | Sep 16, 2025 | --- Data as of 2026-11-09T01:18:40Z UTC. 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