UBUNTU-CVE-2026-46250
In the Linux kernel, the following vulnerability has been resolved: MIPS: Work around LLVM bug when gp is used as global register variable On MIPS, __current_thread_info is defined as global register variable locating in $gp, and is simply assigned with new address during kernel relocation. This however is broken with LLVM, which always restores $gp if it finds $gp is clobbered in any form, including when intentionally through a global register variable. This is against GCC's documentation[1], which requires a callee-saved register used as global register variable not to be restored if it's clobbered. As a result, $gp will continue to point to the unrelocated kernel after the epilog of relocate_kernel(), leading to an early crash in init_idle, [ 0.000000] CPU 0 Unable to handle kernel paging request at virtual address 0000000000000000, epc == ffffffff81afada8, ra == ffffffff81afad90 [ 0.000000] Oops[#1]: [ 0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Tainted: G W 6.19.0-rc5-00262-gd3eeb99bbc99-dirty #188 VOLUNTARY [ 0.000000] Tainted: [W]=WARN [ 0.000000] Hardware name: loongson,loongson64v-4core-virtio [ 0.000000] $ 0 : 0000000000000000 0000000000000000 0000000000000001 0000000000000000 [ 0.000000] $ 4 : ffffffff80b80ec0 ffffffff80b53d48 0000000000000000 00000000000f4240 [ 0.000000] $ 8 : 0000000000000100 ffffffff81d82f80 ffffffff81d82f80 0000000000000001 [ 0.000000] $12 : 0000000000000000 ffffffff81776f58 00000000000005da 0000000000000002 [ 0.000000] $16 : ffffffff80b80e40 0000000000000000 ffffffff80b81614 9800000005dfbe80 [ 0.000000] $20 : 00000000540000e0 ffffffff81980000 0000000000000000 ffffffff80f81c80 [ 0.000000] $24 : 0000000000000a26 ffffffff8114fb90 [ 0.000000] $28 : ffffffff80b50000 ffffffff80b53d40 0000000000000000 ffffffff81afad90 [ 0.000000] Hi : 0000000000000000 [ 0.000000] Lo : 0000000000000000 [ 0.000000] epc : ffffffff81afada8 init_idle+0x130/0x270 [ 0.000000] ra : ffffffff81afad90 init_idle+0x118/0x270 [ 0.000000] Status: 540000e2 KX SX UX KERNEL EXL [ 0.000000] Cause : 00000008 (ExcCode 02) [ 0.000000] BadVA : 0000000000000000 [ 0.000000] PrId : 00006305 (ICT Loongson-3) [ 0.000000] Process swapper (pid: 0, threadinfo=(____ptrval____), task=(____ptrval____), tls=0000000000000000) [ 0.000000] Stack : 9800000005dfbf00 ffffffff8178e950 0000000000000000 0000000000000000 [ 0.000000] 0000000000000000 ffffffff81970000 000000000000003f ffffffff810a6528 [ 0.000000] 0000000000000001 9800000005dfbe80 9800000005dfbf00 ffffffff81980000 [ 0.000000] ffffffff810a6450 ffffffff81afb6c0 0000000000000000 ffffffff810a2258 [ 0.000000] ffffffff81d82ec8 ffffffff8198d010 ffffffff81b67e80 ffffffff8197dd98 [ 0.000000] ffffffff81d81c80 ffffffff81930000 0000000000000040 0000000000000000 [ 0.000000] 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 0.000000] 0000000000000000 000000000000009e ffffffff9fc01000 0000000000000000 [ 0.000000] 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 0.000000] 0000000000000000 ffffffff81ae86dc ffffffff81b3c741 0000000000000002 [ 0.000000] ... [ 0.000000] Call Trace: [ 0.000000] [<ffffffff81afada8>] init_idle+0x130/0x270 [ 0.000000] [<ffffffff81afb6c0>] sched_init+0x5c8/0x6c0 [ 0.000000] [<ffffffff81ae86dc>] start_kernel+0x27c/0x7a8 This bug has been reported to LLVM[2] and affects version from (at least) 18 to 21. Let's work around this by using inline assembly to assign $gp before a fix is widely available.
02 / AFFECTED SOFTWARE
Affected packages
12 explicit affected versions
3 explicit affected versions
11 explicit affected versions
11 explicit affected versions
6 explicit affected versions
6 explicit affected versions
53 explicit affected versions
116 explicit affected versions
87 explicit affected versions
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
19 explicit affected versions
10 explicit affected versions
97 explicit affected versions
59 explicit affected versions
24 explicit affected versions
82 explicit affected versions
83 explicit affected versions
91 explicit affected versions
84 explicit affected versions
76 explicit affected versions
10 explicit affected versions
36 explicit affected versions
26 explicit affected versions
89 explicit affected versions
7 explicit affected versions
84 explicit affected versions
39 explicit affected versions
13 explicit affected versions
85 explicit affected versions
43 explicit affected versions
35 explicit affected versions
49 explicit affected versions
47 explicit affected versions
18 explicit affected versions
40 explicit affected versions
118 explicit affected versions
62 explicit affected versions
44 explicit affected versions
120 explicit affected versions
13 explicit affected versions
4 explicit affected versions
23 explicit affected versions
51 explicit affected versions
124 explicit affected versions
1 explicit affected versions
1 explicit affected versions
21 explicit affected versions
7 explicit affected versions
16 explicit affected versions
10 explicit affected versions
20 explicit affected versions
76 explicit affected versions
47 explicit affected versions
8 explicit affected versions
7 explicit affected versions
12 explicit affected versions
11 explicit affected versions
111 explicit affected versions
7 explicit affected versions
12 explicit affected versions
14 explicit affected versions
13 explicit affected versions
10 explicit affected versions
1 explicit affected versions
7 explicit affected versions
16 explicit affected versions
104 explicit affected versions
12 explicit affected versions
10 explicit affected versions
105 explicit affected versions
12 explicit affected versions
40 explicit affected versions
38 explicit affected versions
43 explicit affected versions
16 explicit affected versions
17 explicit affected versions
27 explicit affected versions
33 explicit affected versions
10 explicit affected versions
37 explicit affected versions
10 explicit affected versions
11 explicit affected versions
3 explicit affected versions
10 explicit affected versions
11 explicit affected versions
65 explicit affected versions
1 explicit affected versions
26 explicit affected versions
9 explicit affected versions
13 explicit affected versions
34 explicit affected versions
1 explicit affected versions
29 explicit affected versions
111 explicit affected versions
13 explicit affected versions
12 explicit affected versions
95 explicit affected versions
40 explicit affected versions
39 explicit affected versions
8 explicit affected versions
1 explicit affected versions
100 explicit affected versions
89 explicit affected versions
132 explicit affected versions
52 explicit affected versions
33 explicit affected versions
23 explicit affected versions
58 explicit affected versions
10 explicit affected versions
19 explicit affected versions
18 explicit affected versions
11 explicit affected versions
5 explicit affected versions
7 explicit affected versions
12 explicit affected versions
10 explicit affected versions
16 explicit affected versions
11 explicit affected versions
138 explicit affected versions
5 explicit affected versions
74 explicit affected versions
132 explicit affected versions
90 explicit affected versions
154 explicit affected versions
10 explicit affected versions
26 explicit affected versions
39 explicit affected versions
10 explicit affected versions
1 explicit affected versions
66 explicit affected versions
35 explicit affected versions
46 explicit affected versions
13 explicit affected versions
45 explicit affected versions
139 explicit affected versions
78 explicit affected versions
16 explicit affected versions
88 explicit affected versions
49 explicit affected versions
116 explicit affected versions
93 explicit affected versions
1 explicit affected versions
7 explicit affected versions
2 explicit affected versions
15 explicit affected versions
51 explicit affected versions
16 explicit affected versions
92 explicit affected versions
18 explicit affected versions
41 explicit affected versions
12 explicit affected versions
70 explicit affected versions
77 explicit affected versions
7 explicit affected versions
27 explicit affected versions
13 explicit affected versions
63 explicit affected versions
121 explicit affected versions
1 explicit affected versions
1 explicit affected versions
98 explicit affected versions
1 explicit affected versions
42 explicit affected versions
8 explicit affected versions
54 explicit affected versions
5 explicit affected versions
8 explicit affected versions
10 explicit affected versions
7 explicit affected versions
45 explicit affected versions
13 explicit affected versions
110 explicit affected versions
72 explicit affected versions
7 explicit affected versions
140 explicit affected versions
8 explicit affected versions
94 explicit affected versions
10 explicit affected versions
12 explicit affected versions
9 explicit affected versions
36 explicit affected versions
108 explicit affected versions
80 explicit affected versions
56 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
49 explicit affected versions
14 explicit affected versions
38 explicit affected versions
167 explicit affected versions
14 explicit affected versions
9 explicit affected versions
17 explicit affected versions
11 explicit affected versions
38 explicit affected versions
17 explicit affected versions
90 explicit affected versions
6 explicit affected versions
7 explicit affected versions
121 explicit affected versions
4 explicit affected versions
79 explicit affected versions
10 explicit affected versions
1 explicit affected versions
1 explicit affected versions
1 explicit affected versions
88 explicit affected versions
78 explicit affected versions
78 explicit affected versions
13 explicit affected versions
43 explicit affected versions
77 explicit affected versions
16 explicit affected versions
119 explicit affected versions
10 explicit affected versions
8 explicit affected versions
44 explicit affected versions
88 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
14 explicit affected versions
11 explicit affected versions
1 explicit affected versions
69 explicit affected versions
123 explicit affected versions
18 explicit affected versions
38 explicit affected versions
77 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: MIPS: Work around LLVM bug when gp is used as global register variable On MIPS, __current_thread_info is defined as global register variable locating in $gp, and is simply assigned with new address during kernel relocation. This however is broken with LLVM, which always restores $gp if it finds $gp is clobbered in any form, including when intentionally through a global register variable. This is against GCC's documentation[1], which requires a callee-saved register used as global register variable not to be restored if it's clobbered. As a result, $gp will continue to point to the unrelocated kernel after the epilog of relocate_kernel(), leading to an early crash in init_idle, [ 0.000000] CPU 0 Unable to handle kernel paging request at virtual address 0000000000000000, epc == ffffffff81afada8, ra == ffffffff81afad90 [ 0.000000] Oops[#1]: [ 0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Tainted: G W 6.19.0-rc5-00262-gd3eeb99bbc99-dirty #188 VOLUNTARY [ 0.000000] Tainted: [W]=WARN [ 0.000000] Hardware name: loongson,loongson64v-4core-virtio [ 0.000000] $ 0 : 0000000000000000 0000000000000000 0000000000000001 0000000000000000 [ 0.000000] $ 4 : ffffffff80b80ec0 ffffffff80b53d48 0000000000000000 00000000000f4240 [ 0.000000] $ 8 : 0000000000000100 ffffffff81d82f80 ffffffff81d82f80 0000000000000001 [ 0.000000] $12 : 0000000000000000 ffffffff81776f58 00000000000005da 0000000000000002 [ 0.000000] $16 : ffffffff80b80e40 0000000000000000 ffffffff80b81614 9800000005dfbe80 [ 0.000000] $20 : 00000000540000e0 ffffffff81980000 0000000000000000 ffffffff80f81c80 [ 0.000000] $24 : 0000000000000a26 ffffffff8114fb90 [ 0.000000] $28 : ffffffff80b50000 ffffffff80b53d40 0000000000000000 ffffffff81afad90 [ 0.000000] Hi : 0000000000000000 [ 0.000000] Lo : 0000000000000000 [ 0.000000] epc : ffffffff81afada8 init_idle+0x130/0x270 [ 0.000000] ra : ffffffff81afad90 init_idle+0x118/0x270 [ 0.000000] Status: 540000e2 KX SX UX KERNEL EXL [ 0.000000] Cause : 00000008 (ExcCode 02) [ 0.000000] BadVA : 0000000000000000 [ 0.000000] PrId : 00006305 (ICT Loongson-3) [ 0.000000] Process swapper (pid: 0, threadinfo=(____ptrval____), task=(____ptrval____), tls=0000000000000000) [ 0.000000] Stack : 9800000005dfbf00 ffffffff8178e950 0000000000000000 0000000000000000 [ 0.000000] 0000000000000000 ffffffff81970000 000000000000003f ffffffff810a6528 [ 0.000000] 0000000000000001 9800000005dfbe80 9800000005dfbf00 ffffffff81980000 [ 0.000000] ffffffff810a6450 ffffffff81afb6c0 0000000000000000 ffffffff810a2258 [ 0.000000] ffffffff81d82ec8 ffffffff8198d010 ffffffff81b67e80 ffffffff8197dd98 [ 0.000000] ffffffff81d81c80 ffffffff81930000 0000000000000040 0000000000000000 [ 0.000000] 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 0.000000] 0000000000000000 000000000000009e ffffffff9fc01000 0000000000000000 [ 0.000000] 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 0.000000] 0000000000000000 ffffffff81ae86dc ffffffff81b3c741 0000000000000002 [ 0.000000] ... [ 0.000000] Call Trace: [ 0.000000] [<ffffffff81afada8>] init_idle+0x130/0x270 [ 0.000000] [<ffffffff81afb6c0>] sched_init+0x5c8/0x6c0 [ 0.000000] [<ffffffff81ae86dc>] start_kernel+0x27c/0x7a8 This bug has been reported to LLVM[2] and affects version from (at least) 18 to 21. Let's work around this by using inline assembly to assign $gp before a fix is widely available.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/30bfc2d6a1132a89a5f1c3b96c59cf3e4d076ea3
- https://ubuntu.com/security/CVE-2026-46250
- https://ubuntu.com/security/notices/USN-8492-1
- https://ubuntu.com/security/notices/USN-8492-2
- https://ubuntu.com/security/notices/USN-8492-3
- https://ubuntu.com/security/notices/USN-8492-4
- https://ubuntu.com/security/notices/USN-8492-5
- https://ubuntu.com/security/notices/USN-8497-1
- https://ubuntu.com/security/notices/USN-8498-1
- https://ubuntu.com/security/notices/USN-8499-1
- https://ubuntu.com/security/notices/USN-8575-1
- https://ubuntu.com/security/notices/USN-8575-2
- https://ubuntu.com/security/notices/USN-8575-3
- https://ubuntu.com/security/notices/USN-8576-1
- https://ubuntu.com/security/notices/USN-8576-2
- https://ubuntu.com/security/notices/USN-8606-1
- https://ubuntu.com/security/notices/USN-8607-1
- https://ubuntu.com/security/notices/USN-8609-1
- https://ubuntu.com/security/notices/USN-8610-1
- https://ubuntu.com/security/notices/USN-8619-1
- https://ubuntu.com/security/notices/USN-8620-1
- https://ubuntu.com/security/notices/USN-8620-2
- https://ubuntu.com/security/notices/USN-8620-3
- https://ubuntu.com/security/notices/USN-8620-4
- https://www.cve.org/CVERecord?id=CVE-2026-46250