CVE-2025-40042— tracing: Fix race condition in kprobe initialization causing NULL pointer dereference
Quick assessment
Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于kprobe初始化过程中存在竞争条件，可能导致空指针取消引用。
Possible ATT&CK Techniques 1 AI
T1058Affected Version Matrix 18
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Linux | Linux | 50d780560785b068c358675c5f0bf6c83b5c373e< 07926ce598a95de6fd874a74fb510e2ebdfd0aae |
affected |
50d780560785b068c358675c5f0bf6c83b5c373e< 9c4951b691bb8d7a004acd010f45144391f85ea6 |
affected | ||
50d780560785b068c358675c5f0bf6c83b5c373e< 95dd33361061f808d1f68616d69ada639e737cfa |
affected | ||
50d780560785b068c358675c5f0bf6c83b5c373e< a6e89ada1ff6b70df73f579071ffa6ade8ae7f98 |
affected | ||
50d780560785b068c358675c5f0bf6c83b5c373e< 1a301228c0a8aedc3154fb1a274456f487416b96 |
affected | ||
50d780560785b068c358675c5f0bf6c83b5c373e< 0fa388ab2c290ef1115ff88ae88e881d0fb2db02 |
affected | ||
50d780560785b068c358675c5f0bf6c83b5c373e< 5ebea6561649d30ec7a18fea23d7f76738dae916 |
affected | ||
50d780560785b068c358675c5f0bf6c83b5c373e< 9cf9aa7b0acfde7545c1a1d912576e9bab28dc6f |
affected | ||
| … +10 more rows | |||
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I. Basic Information for CVE-2025-40042
Vulnerability Information
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Vulnerability Title
tracing: Fix race condition in kprobe initialization causing NULL pointer dereference
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix race condition in kprobe initialization causing NULL pointer dereference
There is a critical race condition in kprobe initialization that can lead to
NULL pointer dereference and kernel crash.
[1135630.084782] Unable to handle kernel paging request at virtual address 0000710a04630000
...
[1135630.260314] pstate: 404003c9 (nZcv DAIF +PAN -UAO)
[1135630.269239] pc : kprobe_perf_func+0x30/0x260
[1135630.277643] lr : kprobe_dispatcher+0x44/0x60
[1135630.286041] sp : ffffaeff4977fa40
[1135630.293441] x29: ffffaeff4977fa40 x28: ffffaf015340e400
[1135630.302837] x27: 0000000000000000 x26: 0000000000000000
[1135630.312257] x25: ffffaf029ed108a8 x24: ffffaf015340e528
[1135630.321705] x23: ffffaeff4977fc50 x22: ffffaeff4977fc50
[1135630.331154] x21: 0000000000000000 x20: ffffaeff4977fc50
[1135630.340586] x19: ffffaf015340e400 x18: 0000000000000000
[1135630.349985] x17: 0000000000000000 x16: 0000000000000000
[1135630.359285] x15: 0000000000000000 x14: 0000000000000000
[1135630.368445] x13: 0000000000000000 x12: 0000000000000000
[1135630.377473] x11: 0000000000000000 x10: 0000000000000000
[1135630.386411] x9 : 0000000000000000 x8 : 0000000000000000
[1135630.395252] x7 : 0000000000000000 x6 : 0000000000000000
[1135630.403963] x5 : 0000000000000000 x4 : 0000000000000000
[1135630.412545] x3 : 0000710a04630000 x2 : 0000000000000006
[1135630.421021] x1 : ffffaeff4977fc50 x0 : 0000710a04630000
[1135630.429410] Call trace:
[1135630.434828] kprobe_perf_func+0x30/0x260
[1135630.441661] kprobe_dispatcher+0x44/0x60
[1135630.448396] aggr_pre_handler+0x70/0xc8
[1135630.454959] kprobe_breakpoint_handler+0x140/0x1e0
[1135630.462435] brk_handler+0xbc/0xd8
[1135630.468437] do_debug_exception+0x84/0x138
[1135630.475074] el1_dbg+0x18/0x8c
[1135630.480582] security_file_permission+0x0/0xd0
[1135630.487426] vfs_write+0x70/0x1c0
[1135630.493059] ksys_write+0x5c/0xc8
[1135630.498638] __arm64_sys_write+0x24/0x30
[1135630.504821] el0_svc_common+0x78/0x130
[1135630.510838] el0_svc_handler+0x38/0x78
[1135630.516834] el0_svc+0x8/0x1b0
kernel/trace/trace_kprobe.c: 1308
0xffff3df8995039ec <kprobe_perf_func+0x2c>: ldr x21, [x24,#120]
include/linux/compiler.h: 294
0xffff3df8995039f0 <kprobe_perf_func+0x30>: ldr x1, [x21,x0]
kernel/trace/trace_kprobe.c
1308: head = this_cpu_ptr(call->perf_events);
1309: if (hlist_empty(head))
1310: return 0;
crash> struct trace_event_call -o
struct trace_event_call {
...
[120] struct hlist_head *perf_events; //(call->perf_event)
...
}
crash> struct trace_event_call ffffaf015340e528
struct trace_event_call {
...
perf_events = 0xffff0ad5fa89f088, //this value is correct, but x21 = 0
...
}
Race Condition Analysis:
The race occurs between kprobe activation and perf_events initialization:
CPU0 CPU1
==== ====
perf_kprobe_init
perf_trace_event_init
tp_event->perf_events = list;(1)
tp_event->class->reg (2)← KPROBE ACTIVE
Debug exception triggers
...
kprobe_dispatcher
kprobe_perf_func (tk->tp.flags & TP_FLAG_PROFILE)
head = this_cpu_ptr(call->perf_events)(3)
(perf_events is still NULL)
Problem:
1. CPU0 executes (1) assigning tp_event->perf_events = list
2. CPU0 executes (2) enabling kprobe functionality via class->reg()
3. CPU1 triggers and reaches kprobe_dispatcher
4. CPU1 checks TP_FLAG_PROFILE - condition passes (step 2 completed)
5. CPU1 calls kprobe_perf_func() and crashes at (3) because
call->perf_events is still NULL
CPU1 sees that kprobe functionality is enabled but does not see that
perf_events has been assigned.
Add pairing read an
---truncated---
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于kprobe初始化过程中存在竞争条件，可能导致空指针取消引用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2025-40042
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|---|
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Patches & Fixes for CVE-2025-40042 (2)
Same Patch Batch · Linux · 2025-10-28 · 58 CVEs total
| CVE-2025-40074 | 9.8 CRITICAL | ipv4: start using dst_dev_rcu() |
| CVE-2025-40043 | 8.8 HIGH | net: nfc: nci: Add parameter validation for packet data |
| CVE-2025-40039 | 8.8 HIGH | ksmbd: Fix race condition in RPC handle list access |
| CVE-2025-40058 | 8.8 HIGH | iommu/vt-d: Disallow dirty tracking if incoherent page walk |
| CVE-2025-40046 | 8.6 HIGH | io_uring/zcrx: fix overshooting recv limit |
| CVE-2025-40068 | 8.4 HIGH | fs: ntfs3: Fix integer overflow in run_unpack() |
| CVE-2025-40075 | 8.1 HIGH | tcp_metrics: use dst_dev_net_rcu() |
| CVE-2025-40026 | 7.9 HIGH | KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O |
| CVE-2025-40027 | 7.8 HIGH | net/9p: fix double req put in p9_fd_cancelled |
| CVE-2025-40054 | 7.8 HIGH | f2fs: fix UAF issue in f2fs_merge_page_bio() |
| CVE-2025-40045 | 7.8 HIGH | ASoC: codecs: wcd937x: set the comp soundwire port correctly |
| CVE-2025-40047 | 7.8 HIGH | io_uring/waitid: always prune wait queue entry in io_waitid_wait() |
| CVE-2025-40051 | 7.8 HIGH | vhost: vringh: Modify the return value check |
| CVE-2025-40025 | 7.8 HIGH | f2fs: fix to do sanity check on node footer for non inode dnode |
| CVE-2025-40061 | 7.8 HIGH | RDMA/rxe: Fix race in do_task() when draining |
| CVE-2025-40064 | 7.8 HIGH | smc: Fix use-after-free in __pnet_find_base_ndev(). |
| CVE-2025-40067 | 7.8 HIGH | fs/ntfs3: reject index allocation if $BITMAP is empty but blocks exist |
| CVE-2025-40069 | 7.8 HIGH | drm/msm: Fix obj leak in VM_BIND error path |
| CVE-2025-40079 | 7.8 HIGH | riscv, bpf: Sign extend struct ops return values properly |
| CVE-2025-40081 | 7.8 HIGH | perf: arm_spe: Prevent overflow in PERF_IDX2OFF() |
Showing top 20 of 58 CVEs. View all on vendor page → →
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Same vendor: Linux
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V. Comments for CVE-2025-40042
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