UBUNTU-CVE-2025-39737
In the Linux kernel, the following vulnerability has been resolved: mm/kmemleak: avoid soft lockup in __kmemleak_do_cleanup() A soft lockup warning was observed on a relative small system x86-64 system with 16 GB of memory when running a debug kernel with kmemleak enabled. watchdog: BUG: soft lockup - CPU#8 stuck for 33s! [kworker/8:1:134] The test system was running a workload with hot unplug happening in parallel. Then kemleak decided to disable itself due to its inability to allocate more kmemleak objects. The debug kernel has its CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE set to 40,000. The soft lockup happened in kmemleak_do_cleanup() when the existing kmemleak objects were being removed and deleted one-by-one in a loop via a workqueue. In this particular case, there are at least 40,000 objects that need to be processed and given the slowness of a debug kernel and the fact that a raw_spinlock has to be acquired and released in __delete_object(), it could take a while to properly handle all these objects. As kmemleak has been disabled in this case, the object removal and deletion process can be further optimized as locking isn't really needed. However, it is probably not worth the effort to optimize for such an edge case that should rarely happen. So the simple solution is to call cond_resched() at periodic interval in the iteration loop to avoid soft lockup.
02 / AFFECTED SOFTWARE
Affected packages
21 explicit affected versions
11 explicit affected versions
12 explicit affected versions
11 explicit affected versions
8 explicit affected versions
53 explicit affected versions
116 explicit affected versions
75 explicit affected versions
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
19 explicit affected versions
10 explicit affected versions
6 explicit affected versions
85 explicit affected versions
57 explicit affected versions
24 explicit affected versions
70 explicit affected versions
70 explicit affected versions
91 explicit affected versions
76 explicit affected versions
65 explicit affected versions
10 explicit affected versions
28 explicit affected versions
26 explicit affected versions
77 explicit affected versions
191 explicit affected versions
7 explicit affected versions
74 explicit affected versions
32 explicit affected versions
13 explicit affected versions
85 explicit affected versions
35 explicit affected versions
35 explicit affected versions
37 explicit affected versions
35 explicit affected versions
18 explicit affected versions
32 explicit affected versions
118 explicit affected versions
64 explicit affected versions
37 explicit affected versions
120 explicit affected versions
13 explicit affected versions
4 explicit affected versions
121 explicit affected versions
23 explicit affected versions
43 explicit affected versions
124 explicit affected versions
1 explicit affected versions
1 explicit affected versions
9 explicit affected versions
16 explicit affected versions
10 explicit affected versions
76 explicit affected versions
39 explicit affected versions
8 explicit affected versions
7 explicit affected versions
111 explicit affected versions
7 explicit affected versions
12 explicit affected versions
14 explicit affected versions
10 explicit affected versions
37 explicit affected versions
1 explicit affected versions
7 explicit affected versions
9 explicit affected versions
104 explicit affected versions
12 explicit affected versions
105 explicit affected versions
12 explicit affected versions
32 explicit affected versions
120 explicit affected versions
31 explicit affected versions
188 explicit affected versions
16 explicit affected versions
23 explicit affected versions
25 explicit affected versions
10 explicit affected versions
10 explicit affected versions
13 explicit affected versions
31 explicit affected versions
3 explicit affected versions
10 explicit affected versions
11 explicit affected versions
52 explicit affected versions
1 explicit affected versions
26 explicit affected versions
3 explicit affected versions
62 explicit affected versions
13 explicit affected versions
144 explicit affected versions
24 explicit affected versions
1 explicit affected versions
29 explicit affected versions
111 explicit affected versions
13 explicit affected versions
12 explicit affected versions
82 explicit affected versions
32 explicit affected versions
32 explicit affected versions
1 explicit affected versions
100 explicit affected versions
77 explicit affected versions
10 explicit affected versions
40 explicit affected versions
33 explicit affected versions
23 explicit affected versions
46 explicit affected versions
11 explicit affected versions
10 explicit affected versions
11 explicit affected versions
5 explicit affected versions
12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
138 explicit affected versions
2 explicit affected versions
5 explicit affected versions
132 explicit affected versions
78 explicit affected versions
165 explicit affected versions
154 explicit affected versions
10 explicit affected versions
26 explicit affected versions
31 explicit affected versions
1 explicit affected versions
54 explicit affected versions
26 explicit affected versions
38 explicit affected versions
11 explicit affected versions
13 explicit affected versions
37 explicit affected versions
139 explicit affected versions
78 explicit affected versions
16 explicit affected versions
76 explicit affected versions
41 explicit affected versions
116 explicit affected versions
3 explicit affected versions
132 explicit affected versions
93 explicit affected versions
1 explicit affected versions
7 explicit affected versions
2 explicit affected versions
51 explicit affected versions
92 explicit affected versions
18 explicit affected versions
33 explicit affected versions
12 explicit affected versions
64 explicit affected versions
65 explicit affected versions
27 explicit affected versions
51 explicit affected versions
121 explicit affected versions
1 explicit affected versions
1 explicit affected versions
98 explicit affected versions
34 explicit affected versions
8 explicit affected versions
42 explicit affected versions
5 explicit affected versions
3 explicit affected versions
8 explicit affected versions
1 explicit affected versions
10 explicit affected versions
7 explicit affected versions
37 explicit affected versions
13 explicit affected versions
110 explicit affected versions
13 explicit affected versions
72 explicit affected versions
7 explicit affected versions
140 explicit affected versions
94 explicit affected versions
10 explicit affected versions
12 explicit affected versions
9 explicit affected versions
25 explicit affected versions
108 explicit affected versions
80 explicit affected versions
56 explicit affected versions
44 explicit affected versions
167 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
42 explicit affected versions
14 explicit affected versions
38 explicit affected versions
9 explicit affected versions
11 explicit affected versions
30 explicit affected versions
13 explicit affected versions
78 explicit affected versions
8 explicit affected versions
7 explicit affected versions
97 explicit affected versions
121 explicit affected versions
4 explicit affected versions
67 explicit affected versions
1 explicit affected versions
1 explicit affected versions
1 explicit affected versions
76 explicit affected versions
11 explicit affected versions
67 explicit affected versions
66 explicit affected versions
13 explicit affected versions
43 explicit affected versions
77 explicit affected versions
119 explicit affected versions
10 explicit affected versions
8 explicit affected versions
36 explicit affected versions
88 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
1 explicit affected versions
69 explicit affected versions
123 explicit affected versions
10 explicit affected versions
30 explicit affected versions
66 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: mm/kmemleak: avoid soft lockup in __kmemleak_do_cleanup() A soft lockup warning was observed on a relative small system x86-64 system with 16 GB of memory when running a debug kernel with kmemleak enabled. watchdog: BUG: soft lockup - CPU#8 stuck for 33s! [kworker/8:1:134] The test system was running a workload with hot unplug happening in parallel. Then kemleak decided to disable itself due to its inability to allocate more kmemleak objects. The debug kernel has its CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE set to 40,000. The soft lockup happened in kmemleak_do_cleanup() when the existing kmemleak objects were being removed and deleted one-by-one in a loop via a workqueue. In this particular case, there are at least 40,000 objects that need to be processed and given the slowness of a debug kernel and the fact that a raw_spinlock has to be acquired and released in __delete_object(), it could take a while to properly handle all these objects. As kmemleak has been disabled in this case, the object removal and deletion process can be further optimized as locking isn't really needed. However, it is probably not worth the effort to optimize for such an edge case that should rarely happen. So the simple solution is to call cond_resched() at periodic interval in the iteration loop to avoid soft lockup.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/d1534ae23c2b6be350c8ab060803fbf6e9682adc
- https://git.kernel.org/stable/c/1ef72a7fedc5bca70e8cc980985790de10d407aa
- https://git.kernel.org/stable/c/8d2d22a55ffe35c38e69795468a7addd1a80e9ce
- https://git.kernel.org/stable/c/926092268efdf1ed7b55cf486356c74a9e7710d1
- https://git.kernel.org/stable/c/9b80430c194e4a114dc663c1025d56b4f3d0153d
- https://git.kernel.org/stable/c/9f1f4e95031f84867c5821540466d62f88dab8ca
- https://git.kernel.org/stable/c/a04de4c40aab9b338dfa989cf4aec70fd187eeb2
- https://git.kernel.org/stable/c/d1534ae23c2b6be350c8ab060803fbf6e9682adc
- https://git.kernel.org/stable/c/e21a3ddd58733ce31afcb1e5dc3cb80a4b5bc29b
- https://git.kernel.org/stable/c/f014c10d190b92aad366e56b445daffcd1c075e4
- https://ubuntu.com/security/CVE-2025-39737
- https://ubuntu.com/security/notices/USN-7909-1
- https://ubuntu.com/security/notices/USN-7909-2
- https://ubuntu.com/security/notices/USN-7909-3
- https://ubuntu.com/security/notices/USN-7909-4
- https://ubuntu.com/security/notices/USN-7909-5
- https://ubuntu.com/security/notices/USN-7910-1
- https://ubuntu.com/security/notices/USN-7910-2
- https://ubuntu.com/security/notices/USN-7933-1
- https://ubuntu.com/security/notices/USN-7938-1
- https://ubuntu.com/security/notices/USN-8028-1
- https://ubuntu.com/security/notices/USN-8028-2
- https://ubuntu.com/security/notices/USN-8028-3
- https://ubuntu.com/security/notices/USN-8028-4
- https://ubuntu.com/security/notices/USN-8028-5
- https://ubuntu.com/security/notices/USN-8028-6
- https://ubuntu.com/security/notices/USN-8028-7
- https://ubuntu.com/security/notices/USN-8028-8
- https://ubuntu.com/security/notices/USN-8031-1
- https://ubuntu.com/security/notices/USN-8031-2
- https://ubuntu.com/security/notices/USN-8031-3
- https://ubuntu.com/security/notices/USN-8052-1
- https://ubuntu.com/security/notices/USN-8052-2
- https://ubuntu.com/security/notices/USN-8074-1
- https://ubuntu.com/security/notices/USN-8074-2
- https://ubuntu.com/security/notices/USN-8126-1
- https://www.cve.org/CVERecord?id=CVE-2025-39737