CVE-2021-4148: general protection fault in wb_timer_fn

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• First message in thread
• Hao Sun
  • Christoph Hellwig
    • Hao Sun
      • Christoph Hellwig
        • Yang Shi

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Date

Mon, 13 Sep 2021 10:00:27 +0800

Subject

general protection fault in wb_timer_fn

Hello,

When using Healer to fuzz the latest Linux kernel, the following crash
was triggered.

HEAD commit: 4b93c544e90e-thunderbolt: test: split up test cases
git tree: upstream
console output:
https://drive.google.com/file/d/1naN-5p-rFgKpHrshO_kQr5f_KlhvFGGU/view?usp=sharing
kernel config: https://drive.google.com/file/d/1c0u2EeRDhRO-ZCxr9MP2VvAtJd6kfg-p/view?usp=sharing
C reproducer: https://drive.google.com/file/d/19EDhssGw_V1oO2vWOPrgQqve0TdFSgvh/view?usp=sharing
Syzlang reproducer:
https://drive.google.com/file/d/13EGCCoaMe9oitrQCfy44BkGVLbKKFP6X/view?usp=sharing
Similar report:
https://groups.google.com/g/syzkaller-bugs/c/H7fKH_5GVSE/m/-1aj5-d1BAAJ

If you fix this issue, please add the following tag to the commit:
Reported-by: Hao Sun [email protected]

general protection fault, probably for non-canonical address
0xdffffc0000000029: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000148-0x000000000000014f]
CPU: 2 PID: 8539 Comm: syz-executor Not tainted 5.14.0+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:latency_exceeded block/blk-wbt.c:237 [inline]
RIP: 0010:wb_timer_fn+0x149/0x2080 block/blk-wbt.c:360
Code: 03 80 3c 02 00 0f 85 08 1c 00 00 48 8b 9b b0 00 00 00 48 b8 00
00 00 00 00 fc ff df 48 8d bb 48 01 00 00 48 89 fa 48 c1 ea 03 <80> 3c
02 00 0f 85 d5 1b 00 00 48 8b 83 48 01 00 00 48 8d 7d 28 48
RSP: 0018:ffffc90000848cd0 EFLAGS: 00010212
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff888014e79c80
RDX: 0000000000000029 RSI: ffff888014e79c80 RDI: 0000000000000148
RBP: ffff88801e2adc00 R08: ffffffff83de2dfd R09: 0000000000000003
R10: 0000000000000005 R11: ffffed1003c55bb0 R12: 0000000000000003
R13: 0000000000000000 R14: ffff8881053bc800 R15: ffff88801e2adcd0
FS: 0000000003176940(0000) GS:ffff888063f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000014d53ad CR3: 000000002e5ff000 CR4: 0000000000350ee0
Call Trace:
<IRQ>
call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421
expire_timers kernel/time/timer.c:1466 [inline]
__run_timers.part.0+0x6b0/0xa90 kernel/time/timer.c:1734
__run_timers kernel/time/timer.c:1715 [inline]
run_timer_softirq+0xb6/0x1d0 kernel/time/timer.c:1747
__do_softirq+0x1d7/0x93b kernel/softirq.c:558
invoke_softirq kernel/softirq.c:432 [inline]
__irq_exit_rcu kernel/softirq.c:636 [inline]
irq_exit_rcu+0xf2/0x130 kernel/softirq.c:648
sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097
</IRQ>
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:write_comp_data+0xe/0x70 kernel/kcov.c:217
Code: 00 8b 89 1c 15 00 00 48 8b 02 48 83 c0 01 48 39 c1 76 07 4c 89
04 c2 48 89 02 c3 90 49 89 fa bf 03 00 00 00 49 89 f1 49 89 d0 <65> 48
8b 34 25 40 f0 01 00 e8 34 ff ff ff 84 c0 74 44 48 8b 86 20
RSP: 0018:ffffc9000106f7f8 EFLAGS: 00000246
RAX: 000000000d0444bb RBX: 80000000fd589217 RCX: ffffffff81ac95bd
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000007 R11: ffffed100247709c R12: 0000000000000000
R13: 0000000000000001 R14: dffffc0000000000 R15: ffff88802e806788
copy_present_pte mm/memory.c:976 [inline]
copy_pte_range mm/memory.c:1070 [inline]
copy_pmd_range mm/memory.c:1156 [inline]
copy_pud_range mm/memory.c:1193 [inline]
copy_p4d_range mm/memory.c:1217 [inline]
copy_page_range+0xf4d/0x4750 mm/memory.c:1290
dup_mmap kernel/fork.c:610 [inline]
dup_mm+0xa50/0x13d0 kernel/fork.c:1454
copy_mm kernel/fork.c:1506 [inline]
copy_process+0x6c23/0x73d0 kernel/fork.c:2195
kernel_clone+0xe7/0x10d0 kernel/fork.c:2585
__do_sys_clone+0xc8/0x110 kernel/fork.c:2702
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x471f0f
Code: ed 0f 85 64 01 00 00 64 4c 8b 0c 25 10 00 00 00 45 31 c0 4d 8d
91 d0 02 00 00 31 d2 31 f6 bf 11 00 20 01 b8 38 00 00 00 0f 05 <48> 3d
00 f0 ff ff 0f 87 f5 00 00 00 41 89 c5 85 c0 0f 85 fc 00 00
RSP: 002b:00007ffc62d06000 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000471f0f
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000003176940
R10: 0000000003176c10 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000005 R14: 00007ffc62d060b0 R15: 00007ffc62d0606c
Modules linked in:
Dumping ftrace buffer:
(ftrace buffer empty)
—[ end trace ef2331b2238dd17a ]—
RIP: 0010:latency_exceeded block/blk-wbt.c:237 [inline]
RIP: 0010:wb_timer_fn+0x149/0x2080 block/blk-wbt.c:360
Code: 03 80 3c 02 00 0f 85 08 1c 00 00 48 8b 9b b0 00 00 00 48 b8 00
00 00 00 00 fc ff df 48 8d bb 48 01 00 00 48 89 fa 48 c1 ea 03 <80> 3c
02 00 0f 85 d5 1b 00 00 48 8b 83 48 01 00 00 48 8d 7d 28 48
RSP: 0018:ffffc90000848cd0 EFLAGS: 00010212
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffff888014e79c80
RDX: 0000000000000029 RSI: ffff888014e79c80 RDI: 0000000000000148
RBP: ffff88801e2adc00 R08: ffffffff83de2dfd R09: 0000000000000003
R10: 0000000000000005 R11: ffffed1003c55bb0 R12: 0000000000000003
R13: 0000000000000000 R14: ffff8881053bc800 R15: ffff88801e2adcd0
FS: 0000000003176940(0000) GS:ffff888063f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000014d53ad CR3: 000000002e5ff000 CR4: 0000000000350ee0
----------------
Code disassembly (best guess):
0: 03 80 3c 02 00 0f add 0xf00023c(%rax),%eax
6: 85 08 test %ecx,(%rax)
8: 1c 00 sbb $0x0,%al
a: 00 48 8b add %cl,-0x75(%rax)
d: 9b fwait
e: b0 00 mov $0x0,%al
10: 00 00 add %al,(%rax)
12: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
19: fc ff df
1c: 48 8d bb 48 01 00 00 lea 0x148(%rbx),%rdi
23: 48 89 fa mov %rdi,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 d5 1b 00 00 jne 0x1c09
34: 48 8b 83 48 01 00 00 mov 0x148(%rbx),%rax
3b: 48 8d 7d 28 lea 0x28(%rbp),%rdi
3f: 48 rex.W%