CVE-2025-37993: can: m_can: m_can_class_allocate_dev(): initialize spin lock on device probe

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-05-29 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: can: m_can: m_can_class_allocate_dev(): initialize spin lock on device probe The spin lock tx_handling_spinlock in struct m_can_classdev is not being initialized. This leads the following spinlock bad magic complaint from the kernel, eg. when trying to send CAN frames with cansend from can-utils: | BUG: spinlock bad magic on CPU#0, cansend/95 | lock: 0xff60000002ec1010, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0 | CPU: 0 UID: 0 PID: 95 Comm: cansend Not tainted 6.15.0-rc3-00032-ga79be02bba5c #5 NONE | Hardware name: MachineWare SIM-V (DT) | Call Trace: | [<ffffffff800133e0>] dump_backtrace+0x1c/0x24 | [<ffffffff800022f2>] show_stack+0x28/0x34 | [<ffffffff8000de3e>] dump_stack_lvl+0x4a/0x68 | [<ffffffff8000de70>] dump_stack+0x14/0x1c | [<ffffffff80003134>] spin_dump+0x62/0x6e | [<ffffffff800883ba>] do_raw_spin_lock+0xd0/0x142 | [<ffffffff807a6fcc>] _raw_spin_lock_irqsave+0x20/0x2c | [<ffffffff80536dba>] m_can_start_xmit+0x90/0x34a | [<ffffffff806148b0>] dev_hard_start_xmit+0xa6/0xee | [<ffffffff8065b730>] sch_direct_xmit+0x114/0x292 | [<ffffffff80614e2a>] __dev_queue_xmit+0x3b0/0xaa8 | [<ffffffff8073b8fa>] can_send+0xc6/0x242 | [<ffffffff8073d1c0>] raw_sendmsg+0x1a8/0x36c | [<ffffffff805ebf06>] sock_write_iter+0x9a/0xee | [<ffffffff801d06ea>] vfs_write+0x184/0x3a6 | [<ffffffff801d0a88>] ksys_write+0xa0/0xc0 | [<ffffffff801d0abc>] __riscv_sys_write+0x14/0x1c | [<ffffffff8079ebf8>] do_trap_ecall_u+0x168/0x212 | [<ffffffff807a830a>] handle_exception+0x146/0x152 Initializing the spin lock in m_can_class_allocate_dev solves that problem.

Affected products

Linux kernel: from 6.9 before 6.12.29; from 6.13 before 6.14.7; 6.15-rc1, 6.15-rc2, 6.15-rc3, 6.15-rc4, 6.15-rc5 — fixed in 6.12.29, 6.14.7

How to fix

Upgrade to a fixed version: Linux kernel 6.12.29, 6.14.7. Check the vendor advisory for mitigations.

References

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