Re: CVS commit: src/sbin/cgdconfig

[Alexander Nasonov <alnsn%yandex.ru@localhost>]

Robert Elz wrote:
>     Date:        Tue, 8 May 2018 19:15:28 +0100
>     From:        Alexander Nasonov <alnsn%yandex.ru@localhost>
>     Message-ID:  <20180508180815.GA5990@neva>
> 
>   | I think it broke the tool. If you run
>   |
>   | cgdconfig -p
>   |
>   | it will crash.
> 
> Sorry, I cannot reproduce this, it looks to work OK to me.
> 
> Can you tell me exactly what command you gave and what
> "it will crash" means (core dump? other failure? ??)

(gdb) b opendisk1
(gdb) run -p
Starting program:
/home/alnsn/netbsd-current/clean/src/sbin/cgdconfig/obj/cgdconfig -p

Breakpoint 1, 0x00007f7ff78111f6 in opendisk1 () from /lib/libutil.so.7
(gdb) x/s $rdi
0x0:    <error: Cannot access memory at address 0x0>     # path=NULL

(gdb) c
Program received signal SIGSEGV, Segmentation fault.
0x00007f7ff7116880 in strchr () from /lib/libc.so.12
(gdb) bt
#0  0x00007f7ff7116880 in strchr () from /lib/libc.so.12
#1  0x00007f7ff78110a8 in ?? () from /lib/libutil.so.7
#2  0x0000000000202bc3 in configure ()
#3  0x00000000002074d8 in main ()

(gdb) disassemble
Dump of assembler code for function strchr:
   0x00007f7ff7116860 <+0>:     movabs $0x101010101010101,%r8
   0x00007f7ff711686a <+10>:    movzbq %sil,%rdx
   0x00007f7ff711686e <+14>:    imul   $0x80,%r8,%r9
   0x00007f7ff7116875 <+21>:    imul   %r8,%rdx
   0x00007f7ff7116879 <+25>:    test   $0x7,%dil
   0x00007f7ff711687d <+29>:    jne    0x7f7ff71168d5 <strchr+117>
   0x00007f7ff711687f <+31>:    nop
=> 0x00007f7ff7116880 <+32>:    mov    (%rdi),%rax
 
(gdb) x $rdi
0x0:    Cannot access memory at address 0x0 # presumably the path argument

If I comment out the if block with opendisk1 inside:

(gdb) run -p
Starting program: /home/alnsn/netbsd-current/clean/src/sbin/cgdconfig/obj/cgdconfig -p
cgdconfig: wrong number of args
usage: cgdconfig [-nv] [-V vmeth] cgd dev [paramsfile]
       cgdconfig -C [-nv] [-f configfile]
       cgdconfig -G [-nv] [-i ivmeth] [-k kgmeth] [-o outfile] paramsfile
       cgdconfig -g [-nv] [-i ivmeth] [-k kgmeth] [-o outfile] alg [keylen]
       cgdconfig -l
       cgdconfig -s [-nv] [-i ivmeth] cgd dev alg [keylen]
       cgdconfig -U [-nv] [-f configfile]
       cgdconfig -u [-nv] cgd
[Inferior 1 (process 26827) exited with code 01]

-- 
Alex