svn commit: r212723 - head/sys/compat/linprocfs

[pluknet]

On 16 September 2010 11:56, Dag-Erling Smorgrav <des at freebsd.org> wrote:
> Author: des
> Date: Thu Sep 16 07:56:34 2010
> New Revision: 212723
> URL: http://svn.freebsd.org/changeset/base/212723
>
> Log:
>  Implement proc/$$/environment.
>
[...]

>  /*
>  * Filler function for proc/pid/environ
>  */
>  static int
>  linprocfs_doprocenviron(PFS_FILL_ARGS)
>  {
> +       int ret;
>
> -       sbuf_printf(sb, "doprocenviron\n%c", '\0');
> -       return (0);
> +       PROC_LOCK(p);

With this change I observe the following sleepable after non-sleepable:

 1st 0xffffff000290b558 process lock (process lock) @
/usr/src/sys/modules/linprocfs/../../compat/linprocfs/linprocfs.c:1049
 2nd 0xffffff00028f8848 user map (user map) @ /usr/src/sys/vm/vm_map.c:3525
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
_witness_debugger() at _witness_debugger+0x2e
witness_checkorder() at witness_checkorder+0x807
_sx_slock() at _sx_slock+0x55
vm_map_lookup() at vm_map_lookup+0x55
vm_fault() at vm_fault+0x113
proc_rwmem() at proc_rwmem+0x7a
linprocfs_doprocenviron() at linprocfs_doprocenviron+0x122
pfs_read() at pfs_read+0x45b
vn_read() at vn_read+0x256
dofileread() at dofileread+0xa1
kern_readv() at kern_readv+0x60
read() at read+0x55
syscallenter() at syscallenter+0x1aa
syscall() at syscall+0x4c
Xfast_syscall() at Xfast_syscall+0xe2
--- syscall (3, FreeBSD ELF64, read), rip = 0x80074134c, rsp =
0x7fffffffe9c8, rbp = 0 ---


> +
> +       if ((ret = p_cansee(td, p)) != 0) {
> +               PROC_UNLOCK(p);
> +               return ret;
> +       }
> +
> +       ret = linprocfs_doargv(td, p, sb, ps_string_env);
> +       PROC_UNLOCK(p);
> +       return (ret);
>  }