net/mlx5e: Fix race between DIM disable and net_dim()
There's a race between disabling DIM and NAPI callbacks using the dim
pointer on the RQ or SQ.
If NAPI checks the DIM state bit and sees it still set, it assumes
`rq->dim` or `sq->dim` is valid. But if DIM gets disabled right after
that check, the pointer might already be set to NULL, leading to a NULL
pointer dereference in net_dim().
Fix this by calling `synchronize_net()` before freeing the DIM context.
This ensures all in-progress NAPI callbacks are finished before the
pointer is cleared.
Kernel log:
BUG: kernel NULL pointer dereference, address: 0000000000000000
...
RIP: 0010:net_dim+0x23/0x190
...
Call Trace:
<TASK>
? __die+0x20/0x60
? page_fault_oops+0x150/0x3e0
? common_interrupt+0xf/0xa0
? sysvec_call_function_single+0xb/0x90
? exc_page_fault+0x74/0x130
? asm_exc_page_fault+0x22/0x30
? net_dim+0x23/0x190
? mlx5e_poll_ico_cq+0x41/0x6f0 [mlx5_core]
? sysvec_apic_timer_interrupt+0xb/0x90
mlx5e_handle_rx_dim+0x92/0xd0 [mlx5_core]
mlx5e_napi_poll+0x2cd/0xac0 [mlx5_core]
? mlx5e_poll_ico_cq+0xe5/0x6f0 [mlx5_core]
busy_poll_stop+0xa2/0x200
? mlx5e_napi_poll+0x1d9/0xac0 [mlx5_core]
? mlx5e_trigger_irq+0x130/0x130 [mlx5_core]
__napi_busy_loop+0x345/0x3b0
? sysvec_call_function_single+0xb/0x90
? asm_sysvec_call_function_single+0x16/0x20
? sysvec_apic_timer_interrupt+0xb/0x90
? pcpu_free_area+0x1e4/0x2e0
napi_busy_loop+0x11/0x20
xsk_recvmsg+0x10c/0x130
sock_recvmsg+0x44/0x70
__sys_recvfrom+0xbc/0x130
? __schedule+0x398/0x890
__x64_sys_recvfrom+0x20/0x30
do_syscall_64+0x4c/0x100
entry_SYSCALL_64_after_hwframe+0x4b/0x53
...
---[ end trace 0000000000000000 ]---
...
---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
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Tracking
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| Source | ID | Title |
|---|---|---|
Debian DSA |
DSA-5975-1 | linux security update |
EUVD |
EUVD-2025-22701 | In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix race between DIM disable and net_dim() There's a race between disabling DIM and NAPI callbacks using the dim pointer on the RQ or SQ. If NAPI checks the DIM state bit and sees it still set, it assumes `rq->dim` or `sq->dim` is valid. But if DIM gets disabled right after that check, the pointer might already be set to NULL, leading to a NULL pointer dereference in net_dim(). Fix this by calling `synchronize_net()` before freeing the DIM context. This ensures all in-progress NAPI callbacks are finished before the pointer is cleared. Kernel log: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... RIP: 0010:net_dim+0x23/0x190 ... Call Trace: <TASK> ? __die+0x20/0x60 ? page_fault_oops+0x150/0x3e0 ? common_interrupt+0xf/0xa0 ? sysvec_call_function_single+0xb/0x90 ? exc_page_fault+0x74/0x130 ? asm_exc_page_fault+0x22/0x30 ? net_dim+0x23/0x190 ? mlx5e_poll_ico_cq+0x41/0x6f0 [mlx5_core] ? sysvec_apic_timer_interrupt+0xb/0x90 mlx5e_handle_rx_dim+0x92/0xd0 [mlx5_core] mlx5e_napi_poll+0x2cd/0xac0 [mlx5_core] ? mlx5e_poll_ico_cq+0xe5/0x6f0 [mlx5_core] busy_poll_stop+0xa2/0x200 ? mlx5e_napi_poll+0x1d9/0xac0 [mlx5_core] ? mlx5e_trigger_irq+0x130/0x130 [mlx5_core] __napi_busy_loop+0x345/0x3b0 ? sysvec_call_function_single+0xb/0x90 ? asm_sysvec_call_function_single+0x16/0x20 ? sysvec_apic_timer_interrupt+0xb/0x90 ? pcpu_free_area+0x1e4/0x2e0 napi_busy_loop+0x11/0x20 xsk_recvmsg+0x10c/0x130 sock_recvmsg+0x44/0x70 __sys_recvfrom+0xbc/0x130 ? __schedule+0x398/0x890 __x64_sys_recvfrom+0x20/0x30 do_syscall_64+0x4c/0x100 entry_SYSCALL_64_after_hwframe+0x4b/0x53 ... ---[ end trace 0000000000000000 ]--- ... ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]--- |
Ubuntu USN |
USN-7879-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7879-2 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-7880-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-7879-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7879-4 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7934-1 | Linux kernel (Azure) vulnerabilities |
Wed, 19 Nov 2025 18:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-362 | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.16:rc5:*:*:*:*:*:* |
|
| Metrics |
cvssV3_1
|
cvssV3_1
|
Tue, 29 Jul 2025 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Sat, 26 Jul 2025 11:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Fri, 25 Jul 2025 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix race between DIM disable and net_dim() There's a race between disabling DIM and NAPI callbacks using the dim pointer on the RQ or SQ. If NAPI checks the DIM state bit and sees it still set, it assumes `rq->dim` or `sq->dim` is valid. But if DIM gets disabled right after that check, the pointer might already be set to NULL, leading to a NULL pointer dereference in net_dim(). Fix this by calling `synchronize_net()` before freeing the DIM context. This ensures all in-progress NAPI callbacks are finished before the pointer is cleared. Kernel log: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... RIP: 0010:net_dim+0x23/0x190 ... Call Trace: <TASK> ? __die+0x20/0x60 ? page_fault_oops+0x150/0x3e0 ? common_interrupt+0xf/0xa0 ? sysvec_call_function_single+0xb/0x90 ? exc_page_fault+0x74/0x130 ? asm_exc_page_fault+0x22/0x30 ? net_dim+0x23/0x190 ? mlx5e_poll_ico_cq+0x41/0x6f0 [mlx5_core] ? sysvec_apic_timer_interrupt+0xb/0x90 mlx5e_handle_rx_dim+0x92/0xd0 [mlx5_core] mlx5e_napi_poll+0x2cd/0xac0 [mlx5_core] ? mlx5e_poll_ico_cq+0xe5/0x6f0 [mlx5_core] busy_poll_stop+0xa2/0x200 ? mlx5e_napi_poll+0x1d9/0xac0 [mlx5_core] ? mlx5e_trigger_irq+0x130/0x130 [mlx5_core] __napi_busy_loop+0x345/0x3b0 ? sysvec_call_function_single+0xb/0x90 ? asm_sysvec_call_function_single+0x16/0x20 ? sysvec_apic_timer_interrupt+0xb/0x90 ? pcpu_free_area+0x1e4/0x2e0 napi_busy_loop+0x11/0x20 xsk_recvmsg+0x10c/0x130 sock_recvmsg+0x44/0x70 __sys_recvfrom+0xbc/0x130 ? __schedule+0x398/0x890 __x64_sys_recvfrom+0x20/0x30 do_syscall_64+0x4c/0x100 entry_SYSCALL_64_after_hwframe+0x4b/0x53 ... ---[ end trace 0000000000000000 ]--- ... ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]--- | |
| Title | net/mlx5e: Fix race between DIM disable and net_dim() | |
| References |
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T21:28:02.590Z
Reserved: 2025-04-16T04:51:24.016Z
Link: CVE-2025-38440
No data.
Status : Analyzed
Published: 2025-07-25T16:15:29.390
Modified: 2025-11-19T18:09:59.133
Link: CVE-2025-38440
OpenCVE Enrichment
Updated: 2025-07-26T11:22:03Z
Debian DSA
EUVD
Ubuntu USN