Description
In the Linux kernel, the following vulnerability has been resolved:
tty: serial: sh-sci: fix RSCI FIFO overrun handling
The receive error handling code is shared between RSCI and all other
SCIF port types, but the RSCI overrun_reg is specified as a memory
offset, while for other SCIF types it is an enum value used to index
into the sci_port_params->regs array, as mentioned above the
sci_serial_in() function.
For RSCI, the overrun_reg is CSR (0x48), causing the sci_getreg() call
inside the sci_handle_fifo_overrun() function to index outside the
bounds of the regs array, which currently has a size of 20, as specified
by SCI_NR_REGS.
Because of this, we end up accessing memory outside of RSCI's
rsci_port_params structure, which, when interpreted as a plat_sci_reg,
happens to have a non-zero size, causing the following WARN when
sci_serial_in() is called, as the accidental size does not match the
supported register sizes.
The existence of the overrun_reg needs to be checked because
SCIx_SH3_SCIF_REGTYPE has overrun_reg set to SCLSR, but SCLSR is not
present in the regs array.
Avoid calling sci_getreg() for port types which don't use standard
register handling.
Use the ops->read_reg() and ops->write_reg() functions to properly read
and write registers for RSCI, and change the type of the status variable
to accommodate the 32-bit CSR register.
sci_getreg() and sci_serial_in() are also called with overrun_reg in the
sci_mpxed_interrupt() interrupt handler, but that code path is not used
for RSCI, as it does not have a muxed interrupt.
------------[ cut here ]------------
Invalid register access
WARNING: CPU: 0 PID: 0 at drivers/tty/serial/sh-sci.c:522 sci_serial_in+0x38/0xac
Modules linked in: renesas_usbhs at24 rzt2h_adc industrialio_adc sha256 cfg80211 bluetooth ecdh_generic ecc rfkill fuse drm backlight ipv6
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.17.0-rc1+ #30 PREEMPT
Hardware name: Renesas RZ/T2H EVK Board based on r9a09g077m44 (DT)
pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : sci_serial_in+0x38/0xac
lr : sci_serial_in+0x38/0xac
sp : ffff800080003e80
x29: ffff800080003e80 x28: ffff800082195b80 x27: 000000000000000d
x26: ffff8000821956d0 x25: 0000000000000000 x24: ffff800082195b80
x23: ffff000180e0d800 x22: 0000000000000010 x21: 0000000000000000
x20: 0000000000000010 x19: ffff000180e72000 x18: 000000000000000a
x17: ffff8002bcee7000 x16: ffff800080000000 x15: 0720072007200720
x14: 0720072007200720 x13: 0720072007200720 x12: 0720072007200720
x11: 0000000000000058 x10: 0000000000000018 x9 : ffff8000821a6a48
x8 : 0000000000057fa8 x7 : 0000000000000406 x6 : ffff8000821fea48
x5 : ffff00033ef88408 x4 : ffff8002bcee7000 x3 : ffff800082195b80
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff800082195b80
Call trace:
sci_serial_in+0x38/0xac (P)
sci_handle_fifo_overrun.isra.0+0x70/0x134
sci_er_interrupt+0x50/0x39c
__handle_irq_event_percpu+0x48/0x140
handle_irq_event+0x44/0xb0
handle_fasteoi_irq+0xf4/0x1a0
handle_irq_desc+0x34/0x58
generic_handle_domain_irq+0x1c/0x28
gic_handle_irq+0x4c/0x140
call_on_irq_stack+0x30/0x48
do_interrupt_handler+0x80/0x84
el1_interrupt+0x34/0x68
el1h_64_irq_handler+0x18/0x24
el1h_64_irq+0x6c/0x70
default_idle_call+0x28/0x58 (P)
do_idle+0x1f8/0x250
cpu_startup_entry+0x34/0x3c
rest_init+0xd8/0xe0
console_on_rootfs+0x0/0x6c
__primary_switched+0x88/0x90
---[ end trace 0000000000000000 ]---
tty: serial: sh-sci: fix RSCI FIFO overrun handling
The receive error handling code is shared between RSCI and all other
SCIF port types, but the RSCI overrun_reg is specified as a memory
offset, while for other SCIF types it is an enum value used to index
into the sci_port_params->regs array, as mentioned above the
sci_serial_in() function.
For RSCI, the overrun_reg is CSR (0x48), causing the sci_getreg() call
inside the sci_handle_fifo_overrun() function to index outside the
bounds of the regs array, which currently has a size of 20, as specified
by SCI_NR_REGS.
Because of this, we end up accessing memory outside of RSCI's
rsci_port_params structure, which, when interpreted as a plat_sci_reg,
happens to have a non-zero size, causing the following WARN when
sci_serial_in() is called, as the accidental size does not match the
supported register sizes.
The existence of the overrun_reg needs to be checked because
SCIx_SH3_SCIF_REGTYPE has overrun_reg set to SCLSR, but SCLSR is not
present in the regs array.
Avoid calling sci_getreg() for port types which don't use standard
register handling.
Use the ops->read_reg() and ops->write_reg() functions to properly read
and write registers for RSCI, and change the type of the status variable
to accommodate the 32-bit CSR register.
sci_getreg() and sci_serial_in() are also called with overrun_reg in the
sci_mpxed_interrupt() interrupt handler, but that code path is not used
for RSCI, as it does not have a muxed interrupt.
------------[ cut here ]------------
Invalid register access
WARNING: CPU: 0 PID: 0 at drivers/tty/serial/sh-sci.c:522 sci_serial_in+0x38/0xac
Modules linked in: renesas_usbhs at24 rzt2h_adc industrialio_adc sha256 cfg80211 bluetooth ecdh_generic ecc rfkill fuse drm backlight ipv6
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.17.0-rc1+ #30 PREEMPT
Hardware name: Renesas RZ/T2H EVK Board based on r9a09g077m44 (DT)
pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : sci_serial_in+0x38/0xac
lr : sci_serial_in+0x38/0xac
sp : ffff800080003e80
x29: ffff800080003e80 x28: ffff800082195b80 x27: 000000000000000d
x26: ffff8000821956d0 x25: 0000000000000000 x24: ffff800082195b80
x23: ffff000180e0d800 x22: 0000000000000010 x21: 0000000000000000
x20: 0000000000000010 x19: ffff000180e72000 x18: 000000000000000a
x17: ffff8002bcee7000 x16: ffff800080000000 x15: 0720072007200720
x14: 0720072007200720 x13: 0720072007200720 x12: 0720072007200720
x11: 0000000000000058 x10: 0000000000000018 x9 : ffff8000821a6a48
x8 : 0000000000057fa8 x7 : 0000000000000406 x6 : ffff8000821fea48
x5 : ffff00033ef88408 x4 : ffff8002bcee7000 x3 : ffff800082195b80
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff800082195b80
Call trace:
sci_serial_in+0x38/0xac (P)
sci_handle_fifo_overrun.isra.0+0x70/0x134
sci_er_interrupt+0x50/0x39c
__handle_irq_event_percpu+0x48/0x140
handle_irq_event+0x44/0xb0
handle_fasteoi_irq+0xf4/0x1a0
handle_irq_desc+0x34/0x58
generic_handle_domain_irq+0x1c/0x28
gic_handle_irq+0x4c/0x140
call_on_irq_stack+0x30/0x48
do_interrupt_handler+0x80/0x84
el1_interrupt+0x34/0x68
el1h_64_irq_handler+0x18/0x24
el1h_64_irq+0x6c/0x70
default_idle_call+0x28/0x58 (P)
do_idle+0x1f8/0x250
cpu_startup_entry+0x34/0x3c
rest_init+0xd8/0xe0
console_on_rootfs+0x0/0x6c
__primary_switched+0x88/0x90
---[ end trace 0000000000000000 ]---
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
Advisories
| Source | ID | Title |
|---|---|---|
 Ubuntu USN |
USN-8029-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-8030-1 | Linux kernel (GCP) vulnerabilities |
| Ubuntu USN |
USN-8029-2 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-8048-1 | Linux kernel (OEM) vulnerabilities |
| Ubuntu USN |
USN-8029-3 | Linux kernel (Azure) vulnerabilities |
References
History
Sat, 06 Dec 2025 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Thu, 04 Dec 2025 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: tty: serial: sh-sci: fix RSCI FIFO overrun handling The receive error handling code is shared between RSCI and all other SCIF port types, but the RSCI overrun_reg is specified as a memory offset, while for other SCIF types it is an enum value used to index into the sci_port_params->regs array, as mentioned above the sci_serial_in() function. For RSCI, the overrun_reg is CSR (0x48), causing the sci_getreg() call inside the sci_handle_fifo_overrun() function to index outside the bounds of the regs array, which currently has a size of 20, as specified by SCI_NR_REGS. Because of this, we end up accessing memory outside of RSCI's rsci_port_params structure, which, when interpreted as a plat_sci_reg, happens to have a non-zero size, causing the following WARN when sci_serial_in() is called, as the accidental size does not match the supported register sizes. The existence of the overrun_reg needs to be checked because SCIx_SH3_SCIF_REGTYPE has overrun_reg set to SCLSR, but SCLSR is not present in the regs array. Avoid calling sci_getreg() for port types which don't use standard register handling. Use the ops->read_reg() and ops->write_reg() functions to properly read and write registers for RSCI, and change the type of the status variable to accommodate the 32-bit CSR register. sci_getreg() and sci_serial_in() are also called with overrun_reg in the sci_mpxed_interrupt() interrupt handler, but that code path is not used for RSCI, as it does not have a muxed interrupt. ------------[ cut here ]------------ Invalid register access WARNING: CPU: 0 PID: 0 at drivers/tty/serial/sh-sci.c:522 sci_serial_in+0x38/0xac Modules linked in: renesas_usbhs at24 rzt2h_adc industrialio_adc sha256 cfg80211 bluetooth ecdh_generic ecc rfkill fuse drm backlight ipv6 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.17.0-rc1+ #30 PREEMPT Hardware name: Renesas RZ/T2H EVK Board based on r9a09g077m44 (DT) pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : sci_serial_in+0x38/0xac lr : sci_serial_in+0x38/0xac sp : ffff800080003e80 x29: ffff800080003e80 x28: ffff800082195b80 x27: 000000000000000d x26: ffff8000821956d0 x25: 0000000000000000 x24: ffff800082195b80 x23: ffff000180e0d800 x22: 0000000000000010 x21: 0000000000000000 x20: 0000000000000010 x19: ffff000180e72000 x18: 000000000000000a x17: ffff8002bcee7000 x16: ffff800080000000 x15: 0720072007200720 x14: 0720072007200720 x13: 0720072007200720 x12: 0720072007200720 x11: 0000000000000058 x10: 0000000000000018 x9 : ffff8000821a6a48 x8 : 0000000000057fa8 x7 : 0000000000000406 x6 : ffff8000821fea48 x5 : ffff00033ef88408 x4 : ffff8002bcee7000 x3 : ffff800082195b80 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff800082195b80 Call trace: sci_serial_in+0x38/0xac (P) sci_handle_fifo_overrun.isra.0+0x70/0x134 sci_er_interrupt+0x50/0x39c __handle_irq_event_percpu+0x48/0x140 handle_irq_event+0x44/0xb0 handle_fasteoi_irq+0xf4/0x1a0 handle_irq_desc+0x34/0x58 generic_handle_domain_irq+0x1c/0x28 gic_handle_irq+0x4c/0x140 call_on_irq_stack+0x30/0x48 do_interrupt_handler+0x80/0x84 el1_interrupt+0x34/0x68 el1h_64_irq_handler+0x18/0x24 el1h_64_irq+0x6c/0x70 default_idle_call+0x28/0x58 (P) do_idle+0x1f8/0x250 cpu_startup_entry+0x34/0x3c rest_init+0xd8/0xe0 console_on_rootfs+0x0/0x6c __primary_switched+0x88/0x90 ---[ end trace 0000000000000000 ]--- | |
| Title | tty: serial: sh-sci: fix RSCI FIFO overrun handling | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T21:45:09.287Z
Reserved: 2025-04-16T07:20:57.180Z
Link: CVE-2025-40222
Vulnrichment
No data.
NVD
Status : Deferred
Published: 2025-12-04T16:16:14.627
Modified: 2026-04-15T00:35:42.020
Link: CVE-2025-40222
Redhat
OpenCVE Enrichment
No data.
Weaknesses
No weakness.