CVE-2025-38136
Analyzed Analyzed - Analysis Complete
BaseFortify

Publication date: 2025-07-03

Last updated on: 2025-12-17

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: usb: renesas_usbhs: Reorder clock handling and power management in probe Reorder the initialization sequence in `usbhs_probe()` to enable runtime PM before accessing registers, preventing potential crashes due to uninitialized clocks. Currently, in the probe path, registers are accessed before enabling the clocks, leading to a synchronous external abort on the RZ/V2H SoC. The problematic call flow is as follows: usbhs_probe() usbhs_sys_clock_ctrl() usbhs_bset() usbhs_write() iowrite16() <-- Register access before enabling clocks Since `iowrite16()` is performed without ensuring the required clocks are enabled, this can lead to access errors. To fix this, enable PM runtime early in the probe function and ensure clocks are acquired before register access, preventing crashes like the following on RZ/V2H: [13.272640] Internal error: synchronous external abort: 0000000096000010 [#1] PREEMPT SMP [13.280814] Modules linked in: cec renesas_usbhs(+) drm_kms_helper fuse drm backlight ipv6 [13.289088] CPU: 1 UID: 0 PID: 195 Comm: (udev-worker) Not tainted 6.14.0-rc7+ #98 [13.296640] Hardware name: Renesas RZ/V2H EVK Board based on r9a09g057h44 (DT) [13.303834] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [13.310770] pc : usbhs_bset+0x14/0x4c [renesas_usbhs] [13.315831] lr : usbhs_probe+0x2e4/0x5ac [renesas_usbhs] [13.321138] sp : ffff8000827e3850 [13.324438] x29: ffff8000827e3860 x28: 0000000000000000 x27: ffff8000827e3ca0 [13.331554] x26: ffff8000827e3ba0 x25: ffff800081729668 x24: 0000000000000025 [13.338670] x23: ffff0000c0f08000 x22: 0000000000000000 x21: ffff0000c0f08010 [13.345783] x20: 0000000000000000 x19: ffff0000c3b52080 x18: 00000000ffffffff [13.352895] x17: 0000000000000000 x16: 0000000000000000 x15: ffff8000827e36ce [13.360009] x14: 00000000000003d7 x13: 00000000000003d7 x12: 0000000000000000 [13.367122] x11: 0000000000000000 x10: 0000000000000aa0 x9 : ffff8000827e3750 [13.374235] x8 : ffff0000c1850b00 x7 : 0000000003826060 x6 : 000000000000001c [13.381347] x5 : 000000030d5fcc00 x4 : ffff8000825c0000 x3 : 0000000000000000 [13.388459] x2 : 0000000000000400 x1 : 0000000000000000 x0 : ffff0000c3b52080 [13.395574] Call trace: [13.398013] usbhs_bset+0x14/0x4c [renesas_usbhs] (P) [13.403076] platform_probe+0x68/0xdc [13.406738] really_probe+0xbc/0x2c0 [13.410306] __driver_probe_device+0x78/0x120 [13.414653] driver_probe_device+0x3c/0x154 [13.418825] __driver_attach+0x90/0x1a0 [13.422647] bus_for_each_dev+0x7c/0xe0 [13.426470] driver_attach+0x24/0x30 [13.430032] bus_add_driver+0xe4/0x208 [13.433766] driver_register+0x68/0x130 [13.437587] __platform_driver_register+0x24/0x30 [13.442273] renesas_usbhs_driver_init+0x20/0x1000 [renesas_usbhs] [13.448450] do_one_initcall+0x60/0x1d4 [13.452276] do_init_module+0x54/0x1f8 [13.456014] load_module+0x1754/0x1c98 [13.459750] init_module_from_file+0x88/0xcc [13.464004] __arm64_sys_finit_module+0x1c4/0x328 [13.468689] invoke_syscall+0x48/0x104 [13.472426] el0_svc_common.constprop.0+0xc0/0xe0 [13.477113] do_el0_svc+0x1c/0x28 [13.480415] el0_svc+0x30/0xcc [13.483460] el0t_64_sync_handler+0x10c/0x138 [13.487800] el0t_64_sync+0x198/0x19c [13.491453] Code: 2a0103e1 12003c42 12003c63 8b010084 (79400084) [13.497522] ---[ end trace 0000000000000000 ]---
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Meta Information
Published
2025-07-03
Last Modified
2025-12-17
Generated
2026-05-06
AI Q&A
2025-07-03
EPSS Evaluated
2026-05-05
NVD
CVE-2025-38136
Affected Vendors & Products
Showing 8 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 3.0 (inc) to 5.4.295 (exc)
linux linux_kernel From 5.5 (inc) to 5.10.239 (exc)
linux linux_kernel From 5.11 (inc) to 5.15.186 (exc)
linux linux_kernel From 5.16 (inc) to 6.1.142 (exc)
linux linux_kernel From 6.2 (inc) to 6.6.94 (exc)
linux linux_kernel From 6.7 (inc) to 6.12.34 (exc)
linux linux_kernel From 6.13 (inc) to 6.15.3 (exc)
debian debian_linux 11.0
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-908 The product uses or accesses a resource that has not been initialized.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability occurs in the Linux kernel's Renesas USBHS driver where the initialization sequence in the usbhs_probe() function accesses hardware registers before enabling the necessary clocks. This improper sequence can cause a synchronous external abort (crash) on certain hardware like the Renesas RZ/V2H SoC because the registers are accessed without the required clocks being active. The fix involves reordering the initialization to enable runtime power management and clocks before any register access, preventing these crashes.


How can this vulnerability impact me? :

If your system uses the affected Renesas USBHS driver on hardware like the RZ/V2H SoC, this vulnerability can cause system crashes due to improper register access before clocks are enabled. This can lead to instability, unexpected reboots, or failures in USB functionality, potentially disrupting normal operations.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by monitoring the system logs for kernel error messages related to the renesas_usbhs driver, specifically looking for synchronous external abort errors during usbhs_probe execution. You can check the kernel log using commands like 'dmesg | grep renesas_usbhs' or 'journalctl -k | grep renesas_usbhs' to identify crash traces similar to those described in the vulnerability report.


What immediate steps should I take to mitigate this vulnerability?

The immediate mitigation step is to update the Linux kernel to a version where the usb: renesas_usbhs driver has been fixed by reordering clock handling and power management in the usbhs_probe function. This ensures runtime power management is enabled before register access, preventing crashes. Until the update is applied, avoid using affected hardware or modules that trigger the renesas_usbhs driver to reduce the risk of system crashes.


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