UBUNTU-CVE-2025-38727
In the Linux kernel, the following vulnerability has been resolved: netlink: avoid infinite retry looping in netlink_unicast() netlink_attachskb() checks for the socket's read memory allocation constraints. Firstly, it has: rmem < READ_ONCE(sk->sk_rcvbuf) to check if the just increased rmem value fits into the socket's receive buffer. If not, it proceeds and tries to wait for the memory under: rmem + skb->truesize > READ_ONCE(sk->sk_rcvbuf) The checks don't cover the case when skb->truesize + sk->sk_rmem_alloc is equal to sk->sk_rcvbuf. Thus the function neither successfully accepts these conditions, nor manages to reschedule the task - and is called in retry loop for indefinite time which is caught as: rcu: INFO: rcu_sched self-detected stall on CPU rcu: 0-....: (25999 ticks this GP) idle=ef2/1/0x4000000000000000 softirq=262269/262269 fqs=6212 (t=26000 jiffies g=230833 q=259957) NMI backtrace for cpu 0 CPU: 0 PID: 22 Comm: kauditd Not tainted 5.10.240 #68 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc42 04/01/2014 Call Trace: <IRQ> dump_stack lib/dump_stack.c:120 nmi_cpu_backtrace.cold lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace lib/nmi_backtrace.c:62 rcu_dump_cpu_stacks kernel/rcu/tree_stall.h:335 rcu_sched_clock_irq.cold kernel/rcu/tree.c:2590 update_process_times kernel/time/timer.c:1953 tick_sched_handle kernel/time/tick-sched.c:227 tick_sched_timer kernel/time/tick-sched.c:1399 __hrtimer_run_queues kernel/time/hrtimer.c:1652 hrtimer_interrupt kernel/time/hrtimer.c:1717 __sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1113 asm_call_irq_on_stack arch/x86/entry/entry_64.S:808 </IRQ> netlink_attachskb net/netlink/af_netlink.c:1234 netlink_unicast net/netlink/af_netlink.c:1349 kauditd_send_queue kernel/audit.c:776 kauditd_thread kernel/audit.c:897 kthread kernel/kthread.c:328 ret_from_fork arch/x86/entry/entry_64.S:304 Restore the original behavior of the check which commit in Fixes accidentally missed when restructuring the code. Found by Linux Verification Center (linuxtesting.org).
02 / AFFECTED SOFTWARE
Affected packages
11 explicit affected versions
73 explicit affected versions
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
19 explicit affected versions
6 explicit affected versions
83 explicit affected versions
24 explicit affected versions
68 explicit affected versions
68 explicit affected versions
74 explicit affected versions
63 explicit affected versions
10 explicit affected versions
26 explicit affected versions
75 explicit affected versions
7 explicit affected versions
72 explicit affected versions
13 explicit affected versions
35 explicit affected versions
35 explicit affected versions
33 explicit affected versions
18 explicit affected versions
31 explicit affected versions
64 explicit affected versions
13 explicit affected versions
4 explicit affected versions
23 explicit affected versions
1 explicit affected versions
21 explicit affected versions
16 explicit affected versions
10 explicit affected versions
8 explicit affected versions
7 explicit affected versions
12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
14 explicit affected versions
10 explicit affected versions
1 explicit affected versions
7 explicit affected versions
12 explicit affected versions
12 explicit affected versions
29 explicit affected versions
10 explicit affected versions
37 explicit affected versions
13 explicit affected versions
10 explicit affected versions
50 explicit affected versions
26 explicit affected versions
13 explicit affected versions
22 explicit affected versions
29 explicit affected versions
13 explicit affected versions
80 explicit affected versions
75 explicit affected versions
38 explicit affected versions
33 explicit affected versions
23 explicit affected versions
44 explicit affected versions
10 explicit affected versions
11 explicit affected versions
12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
60 explicit affected versions
76 explicit affected versions
10 explicit affected versions
26 explicit affected versions
52 explicit affected versions
13 explicit affected versions
16 explicit affected versions
76 explicit affected versions
3 explicit affected versions
7 explicit affected versions
51 explicit affected versions
12 explicit affected versions
63 explicit affected versions
63 explicit affected versions
27 explicit affected versions
49 explicit affected versions
8 explicit affected versions
40 explicit affected versions
5 explicit affected versions
3 explicit affected versions
8 explicit affected versions
10 explicit affected versions
7 explicit affected versions
13 explicit affected versions
13 explicit affected versions
7 explicit affected versions
10 explicit affected versions
12 explicit affected versions
23 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
45 explicit affected versions
37 explicit affected versions
14 explicit affected versions
38 explicit affected versions
9 explicit affected versions
11 explicit affected versions
76 explicit affected versions
7 explicit affected versions
4 explicit affected versions
65 explicit affected versions
1 explicit affected versions
74 explicit affected versions
65 explicit affected versions
64 explicit affected versions
13 explicit affected versions
43 explicit affected versions
10 explicit affected versions
8 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
11 explicit affected versions
1 explicit affected versions
64 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: netlink: avoid infinite retry looping in netlink_unicast() netlink_attachskb() checks for the socket's read memory allocation constraints. Firstly, it has: rmem < READ_ONCE(sk->sk_rcvbuf) to check if the just increased rmem value fits into the socket's receive buffer. If not, it proceeds and tries to wait for the memory under: rmem + skb->truesize > READ_ONCE(sk->sk_rcvbuf) The checks don't cover the case when skb->truesize + sk->sk_rmem_alloc is equal to sk->sk_rcvbuf. Thus the function neither successfully accepts these conditions, nor manages to reschedule the task - and is called in retry loop for indefinite time which is caught as: rcu: INFO: rcu_sched self-detected stall on CPU rcu: 0-....: (25999 ticks this GP) idle=ef2/1/0x4000000000000000 softirq=262269/262269 fqs=6212 (t=26000 jiffies g=230833 q=259957) NMI backtrace for cpu 0 CPU: 0 PID: 22 Comm: kauditd Not tainted 5.10.240 #68 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc42 04/01/2014 Call Trace: <IRQ> dump_stack lib/dump_stack.c:120 nmi_cpu_backtrace.cold lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace lib/nmi_backtrace.c:62 rcu_dump_cpu_stacks kernel/rcu/tree_stall.h:335 rcu_sched_clock_irq.cold kernel/rcu/tree.c:2590 update_process_times kernel/time/timer.c:1953 tick_sched_handle kernel/time/tick-sched.c:227 tick_sched_timer kernel/time/tick-sched.c:1399 __hrtimer_run_queues kernel/time/hrtimer.c:1652 hrtimer_interrupt kernel/time/hrtimer.c:1717 __sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1113 asm_call_irq_on_stack arch/x86/entry/entry_64.S:808 </IRQ> netlink_attachskb net/netlink/af_netlink.c:1234 netlink_unicast net/netlink/af_netlink.c:1349 kauditd_send_queue kernel/audit.c:776 kauditd_thread kernel/audit.c:897 kthread kernel/kthread.c:328 ret_from_fork arch/x86/entry/entry_64.S:304 Restore the original behavior of the check which commit in Fixes accidentally missed when restructuring the code. Found by Linux Verification Center (linuxtesting.org).
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/759dfc7d04bab1b0b86113f1164dc1fec192b859
- https://git.kernel.org/stable/c/346c820ef5135cf062fa3473da955ef8c5fb6929
- https://git.kernel.org/stable/c/44ddd7b1ae0b7edb2c832eb16798c827a05e58f0
- https://git.kernel.org/stable/c/47d49fd07f86d1f55ea1083287303d237e9e0922
- https://git.kernel.org/stable/c/6bee383ff83352a693d03efdf27cdd80742f71b2
- https://git.kernel.org/stable/c/759dfc7d04bab1b0b86113f1164dc1fec192b859
- https://git.kernel.org/stable/c/78fcd69d55c5f11d7694c547eca767a1cfd38ec4
- https://git.kernel.org/stable/c/d42b71a34f6b8a2d5c53df81169b03b8d8b5cf4e
- https://git.kernel.org/stable/c/e8edc7de688791a337c068693f22e8d8b869df71
- https://git.kernel.org/stable/c/f324959ad47e62e3cadaffa65d3cff790fb48529
- https://ubuntu.com/security/CVE-2025-38727
- https://ubuntu.com/security/notices/USN-7829-1
- https://ubuntu.com/security/notices/USN-7829-2
- https://ubuntu.com/security/notices/USN-7829-3
- https://ubuntu.com/security/notices/USN-7829-4
- https://ubuntu.com/security/notices/USN-7829-5
- https://ubuntu.com/security/notices/USN-7829-6
- https://ubuntu.com/security/notices/USN-7933-1
- https://www.cve.org/CVERecord?id=CVE-2025-38727