CVE-2025-40164
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-11-12

Last updated on: 2026-02-26

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: usbnet: Fix using smp_processor_id() in preemptible code warnings Syzbot reported the following warning: BUG: using smp_processor_id() in preemptible [00000000] code: dhcpcd/2879 caller is usbnet_skb_return+0x74/0x490 drivers/net/usb/usbnet.c:331 CPU: 1 UID: 0 PID: 2879 Comm: dhcpcd Not tainted 6.15.0-rc4-syzkaller-00098-g615dca38c2ea #0 PREEMPT(voluntary) Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:120 check_preemption_disabled+0xd0/0xe0 lib/smp_processor_id.c:49 usbnet_skb_return+0x74/0x490 drivers/net/usb/usbnet.c:331 usbnet_resume_rx+0x4b/0x170 drivers/net/usb/usbnet.c:708 usbnet_change_mtu+0x1be/0x220 drivers/net/usb/usbnet.c:417 __dev_set_mtu net/core/dev.c:9443 [inline] netif_set_mtu_ext+0x369/0x5c0 net/core/dev.c:9496 netif_set_mtu+0xb0/0x160 net/core/dev.c:9520 dev_set_mtu+0xae/0x170 net/core/dev_api.c:247 dev_ifsioc+0xa31/0x18d0 net/core/dev_ioctl.c:572 dev_ioctl+0x223/0x10e0 net/core/dev_ioctl.c:821 sock_do_ioctl+0x19d/0x280 net/socket.c:1204 sock_ioctl+0x42f/0x6a0 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f For historical and portability reasons, the netif_rx() is usually run in the softirq or interrupt context, this commit therefore add local_bh_disable/enable() protection in the usbnet_resume_rx().
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Meta Information
Published
2025-11-12
Last Modified
2026-02-26
Generated
2026-06-16
AI Q&A
2025-11-13
EPSS Evaluated
2026-06-15
NVD
CVE-2025-40164
Affected Vendors & Products
Showing 8 associated CPEs
Vendor Product Version / Range
linux linux_kernel 4.7
linux linux_kernel 4.7
linux linux_kernel From 5.16 (inc) to 6.1.162 (exc)
linux linux_kernel From 6.2 (inc) to 6.6.122 (exc)
linux linux_kernel From 6.7 (inc) to 6.12.64 (exc)
linux linux_kernel 6.18
linux linux_kernel From 4.7.1 (inc) to 5.15.199 (exc)
linux linux_kernel From 6.13 (inc) to 6.17.5 (exc)
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability involves the Linux kernel's usbnet driver using the function smp_processor_id() in preemptible code, which is unsafe and causes warnings. The issue occurs because smp_processor_id() should not be called in code that can be preempted, as it may lead to incorrect CPU identification. The fix involved adding local_bh_disable/enable() protection in the usbnet_resume_rx() function to ensure proper context and prevent these warnings.

Impact Analysis

The vulnerability can cause instability or unexpected behavior in the Linux kernel's USB network driver due to improper use of smp_processor_id() in preemptible code. This could potentially lead to kernel warnings or bugs affecting network functionality over USB devices, possibly impacting system reliability.

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