BUG: unable to handle kernel NULL pointer dereference in rcu_core
From: Sanan Hasanov
Date: Mon Feb 27 2023 - 01:23:30 EST
Good day, dear maintainers,
We found a bug using a modified kernel configuration file used by syzbot.
We enhanced the coverage of the configuration file using our tool, klocalizer.
Kernel Branch: 6.2.0-next-20230221
Kernel config: https://drive.google.com/file/d/1QKAQV11zjOwISifUc-skRBoTo3EXhutY/view?usp=share_link
C Reproducer: Unfortunately, there is no reproducer yet.
Thank you!
Best regards,
Sanan Hasanov
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 53756067 P4D 53756067 PUD 0
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 7 PID: 0 Comm: swapper/7 Not tainted 6.2.0-next-20230221 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc900003f8e48 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888100833900 RCX: 00000000b9582f6c
RDX: 1ffff11020106853 RSI: ffffffff816b2769 RDI: ffff888043f64708
RBP: 000000000000000c R08: 0000000000000000 R09: ffffffff900b895f
R10: fffffbfff201712b R11: 000000000008e001 R12: dffffc0000000000
R13: ffffc900003f8ec8 R14: ffff888043f64708 R15: 000000000000000b
FS: 0000000000000000(0000) GS:ffff888119f80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000054e64000 CR4: 0000000000350ee0
Call Trace:
<IRQ>
rcu_core+0x85d/0x1960
__do_softirq+0x2e5/0xae2
__irq_exit_rcu+0x11d/0x190
irq_exit_rcu+0x9/0x20
sysvec_apic_timer_interrupt+0x97/0xc0
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:default_idle+0xf/0x20
Code: 89 07 49 c7 c0 08 00 00 00 4d 29 c8 4c 01 c7 4c 29 c2 e9 76 ff ff ff cc cc cc cc f3 0f 1e fa eb 07 0f 00 2d e3 8a 34 00 fb f4 <fa> c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 f3 0f 1e fa 65
RSP: 0018:ffffc9000017fe00 EFLAGS: 00000202
RAX: 0000000000dfbea1 RBX: dffffc0000000000 RCX: ffffffff89b1da9c
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000007 R08: 0000000000000001 R09: ffff888119fb6c23
R10: ffffed10233f6d84 R11: dffffc0000000000 R12: 0000000000000003
R13: ffff888100833900 R14: ffffffff8e112850 R15: 0000000000000000
default_idle_call+0x67/0xa0
do_idle+0x361/0x440
cpu_startup_entry+0x18/0x20
start_secondary+0x256/0x300
secondary_startup_64_no_verify+0xce/0xdb
</TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc900003f8e48 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888100833900 RCX: 00000000b9582f6c
RDX: 1ffff11020106853 RSI: ffffffff816b2769 RDI: ffff888043f64708
RBP: 000000000000000c R08: 0000000000000000 R09: ffffffff900b895f
R10: fffffbfff201712b R11: 000000000008e001 R12: dffffc0000000000
R13: ffffc900003f8ec8 R14: ffff888043f64708 R15: 000000000000000b
FS: 0000000000000000(0000) GS:ffff888119f80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000054e64000 CR4: 0000000000350ee0
----------------
Code disassembly (best guess):
0: 89 07 mov %eax,(%rdi)
2: 49 c7 c0 08 00 00 00 mov $0x8,%r8
9: 4d 29 c8 sub %r9,%r8
c: 4c 01 c7 add %r8,%rdi
f: 4c 29 c2 sub %r8,%rdx
12: e9 76 ff ff ff jmp 0xffffff8d
17: cc int3
18: cc int3
19: cc int3
1a: cc int3
1b: f3 0f 1e fa endbr64
1f: eb 07 jmp 0x28
21: 0f 00 2d e3 8a 34 00 verw 0x348ae3(%rip) # 0x348b0b
28: fb sti
29: f4 hlt
* 2a: fa cli <-- trapping instruction
2b: c3 ret
2c: 66 66 2e 0f 1f 84 00 data16 cs nopw 0x0(%rax,%rax,1)
33: 00 00 00 00
37: 0f 1f 40 00 nopl 0x0(%rax)
3b: f3 0f 1e fa endbr64
3f: 65 gs