Re: [x86/kprobes] 413d31338f: kernel_BUG_at_mm/vmalloc.c

[Masami Hiramatsu]

Hi,

> +
>  static int arch_copy_kprobe(struct kprobe *p)
>  {
>  	struct insn insn;
>  	kprobe_opcode_t buf[MAX_INSN_SIZE];
>  	int len;
>  
> +	memset(&p->ainsn, 0, sizeof(p->ainsn));

Oops, I missed to clear the ainsn.insn here. This must be fixed.

Thanks,

On Fri, 18 Dec 2020 09:02:21 +0800
kernel test robot <oliver.sang@xxxxxxxxx> wrote:

> 
> Greeting,
> 
> FYI, we noticed the following commit (built with gcc-9):
> 
> commit: 413d31338fca081133c508bcabc57854765f43df ("[PATCH 1/1] x86/kprobes: Do not decode opcode in resume_execution()")
> url: https://github.com/0day-ci/linux/commits/Masami-Hiramatsu/x86-kprobes-Classify-opcode-while-preparing-kprobe/20201206-221324
> base: https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git 238c91115cd05c71447ea071624a4c9fe661f970
> 
> in testcase: trinity
> version: trinity-static-i386-x86_64-f93256fb_2019-08-28
> with following parameters:
> 
> 	runtime: 300s
> 
> test-description: Trinity is a linux system call fuzz tester.
> test-url: http://codemonkey.org.uk/projects/trinity/
> 
> 
> on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 8G
> 
> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
> 
> 
> +------------------------------------------+------------+------------+
> |                                          | 238c91115c | 413d31338f |
> +------------------------------------------+------------+------------+
> | boot_successes                           | 8          | 0          |
> | boot_failures                            | 0          | 8          |
> | kernel_BUG_at_mm/vmalloc.c               | 0          | 8          |
> | invalid_opcode:#[##]                     | 0          | 8          |
> | EIP:vmalloc_to_page                      | 0          | 8          |
> | Kernel_panic-not_syncing:Fatal_exception | 0          | 8          |
> +------------------------------------------+------------+------------+
> 
> 
> If you fix the issue, kindly add following tag
> Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
> 
> 
> [    8.468076] kernel BUG at mm/vmalloc.c:364!
> [    8.468257] invalid opcode: 0000 [#1] PREEMPT SMP PTI
> [    8.468344] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.9.0-rc7-00002-g413d31338fca08 #2
> [    8.468344] EIP: vmalloc_to_page+0x27/0x107
> [    8.468344] Code: 89 c8 c3 55 89 c2 89 c1 c1 e9 1e 89 e5 57 56 53 53 a1 64 06 cb c1 89 55 f0 8d 1c c8 89 d0 e8 9d ff ff ff 85 c0 8b 55 f0 75 02 <0f> 0b 8b 03 8b 4b 04 89 c6 81 e6 18 0e 00 00 74 02 0f 0b 89 c3 81
> [    8.468344] EAX: 00000000 EBX: c1f6a000 ECX: 00000000 EDX: 00000000
> [    8.468344] ESI: d087bda5 EDI: d087bda5 EBP: d087bce0 ESP: d087bcd0
> [    8.468344] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010246
> [    8.468344] CR0: 80050033 CR2: 00000000 CR3: 01f6a000 CR4: 000406b0
> [    8.468344] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
> [    8.468344] DR6: fffe0ff0 DR7: 00000400
> [    8.468344] Call Trace:
> [    8.468344]  __text_poke+0x4c/0x28f
> [    8.468344]  ? insn_get_displacement+0x1b/0xce
> [    8.468344]  ? cmp_ex_sort+0x17/0x17
> [    8.468344]  text_poke+0x35/0x3a
> [    8.468344]  arch_copy_kprobe+0x12b/0x148
> [    8.468344]  arch_prepare_kprobe+0x48/0x6a
> [    8.468344]  register_kprobe+0x27f/0x374
> [    8.468344]  __register_trace_kprobe+0x6e/0x73
> [    8.468344]  register_trace_kprobe+0x140/0x282
> [    8.468344]  ? traceprobe_set_print_fmt+0x40/0x58
> [    8.468344]  trace_kprobe_create+0x33e/0x3c3
> [    8.468344]  ? __kmalloc+0xc1/0xcd
> [    8.468344]  ? argv_split+0x5b/0xb9
> [    8.468344]  ? trace_kprobe_create+0x3c3/0x3c3
> [    8.468344]  create_or_delete_trace_kprobe+0x1b/0x27
> [    8.468344]  trace_run_command+0x48/0x6b
> [    8.468344]  trace_kprobe_run_command+0xf/0x11
> [    8.468344]  dynevent_create+0xb/0xd
> [    8.468344]  kprobe_event_gen_test_init+0x82/0x1e2
> [    8.468344]  ? kprobe_event_cmd_init+0x13/0x13
> [    8.468344]  ? init_trace_printk+0xf/0xf
> [    8.468344]  do_one_initcall+0xaa/0x1d4
> [    8.468344]  ? rdinit_setup+0x21/0x21
> [    8.468344]  ? trace_initcall_level+0x72/0x76
> [    8.468344]  do_initcalls+0xa8/0xc8
> [    8.468344]  kernel_init_freeable+0x94/0xb9
> [    8.468344]  ? rest_init+0xce/0xce
> [    8.468344]  kernel_init+0x8/0xe4
> [    8.468344]  ret_from_fork+0x1c/0x28
> [    8.468344] Modules linked in:
> [    8.476471] ---[ end trace 543d3449d7fd5d3a ]---
> 
> 
> To reproduce:
> 
>         # build kernel
> 	cd linux
> 	cp config-5.9.0-rc7-00002-g413d31338fca08 .config
> 	make HOSTCC=gcc-9 CC=gcc-9 ARCH=i386 olddefconfig prepare modules_prepare bzImage
> 
>         git clone https://github.com/intel/lkp-tests.git
>         cd lkp-tests
>         bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email
> 
> 
> 
> Thanks,
> Oliver Sang
> 


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>