Subject: bug#17622: 24.4.50; bootstrap failure

From: Fabrice Popineau <[email-masked]>
Date: Thu, 29 May 2014 15:54:23 +0200

This should fix the problem:

--- ../trunk/src/buffer.c       2014-05-29 15:51:11.632003900 +0200
+++ src/buffer.c        2014-05-29 15:50:54.192190300 +0200
@@ -4703,11 +4703,6 @@

 static int mmap_fd;

-/* Temporary storage for mmap_set_vars, see there.  */
-
-static struct mmap_region *mmap_regions_1;
-static int mmap_fd_1;
-
 /* Page size on this system.  */

 static int mmap_page_size;
@@ -5282,6 +5277,9 @@
   {
     struct buffer *b;

+    mmap_regions = NULL;
+    mmap_fd = -1;
+
     /* We cannot dump buffers with meaningful addresses that can be
        used by the dumped Emacs.  We map new memory for them here.  */
     FOR_EACH_BUFFER (b)

by initializing explicitly variables that need it. We can also remove
unsused variables.
Waiting for confirmation (or failure!).

Fabrice

2014-05-29 14:55 GMT+02:00 Fabrice Popineau <[email-masked]>:

> Probably ok because I ran like this for a while,
> but I wonder if it couldn't be handled at the beginning of
> bufffer.c:init_buffer() instead.
> What I suggest is do what mmap_set_vars(0) does
> inside init_buffer() rather than reinstate mmap_set_vars().
> Not a great advantage, except to clarify that these pointers should be
> initialized
> when starting the dumped emacs instead of relying on what is dumped.
>
> Fabrice
>
>
>
>
>
>
> 2014-05-29 14:38 GMT+02:00 Ken Brown <[email-masked]>:
>
> On 5/29/2014 12:56 AM, Katsumi Yamaoka wrote:
>>
>>> I verified simply reverting r117168 builds Emacs successfully on
>>> Cygwin.
>>>
>>
>> The removal of mmap_set_vars is what caused the problem.  The following
>> patch fixes restores mmap_set_vars and fixes the problem.  Eli and Fabrice,
>> is the w32 build still OK with this patch?
>>
>> === modified file 'src/buffer.c'
>> --- src/buffer.c        2014-05-27 17:31:17 +0000
>> +++ src/buffer.c        2014-05-29 12:23:53 +0000
>> @@ -4855,6 +4855,38 @@
>>  }
>>
>>
>> +/* Set or reset variables holding references to mapped regions.
>> +   If not RESTORE_P, set all variables to null.  If RESTORE_P, set all
>> +   variables to the start of the user-areas of mapped regions.
>> +
>> +   This function is called from Fdump_emacs to ensure that the dumped
>> +   Emacs doesn't contain references to memory that won't be mapped
>> +   when Emacs starts.  */
>> +
>> +void
>> +mmap_set_vars (bool restore_p)
>> +{
>> +  struct mmap_region *r;
>> +
>> +  if (restore_p)
>> +    {
>> +      mmap_regions = mmap_regions_1;
>> +      mmap_fd = mmap_fd_1;
>> +      for (r = mmap_regions; r; r = r->next)
>> +       *r->var = MMAP_USER_AREA (r);
>> +    }
>> +  else
>> +    {
>> +      for (r = mmap_regions; r; r = r->next)
>> +       *r->var = NULL;
>> +      mmap_regions_1 = mmap_regions;
>> +      mmap_regions = NULL;
>> +      mmap_fd_1 = mmap_fd;
>> +      mmap_fd = -1;
>> +    }
>> +}
>> +
>> +
>>  /* Allocate a block of storage large enough to hold NBYTES bytes of
>>     data.  A pointer to the data is returned in *VAR.  VAR is thus the
>>     address of some variable which will use the data area.
>>
>> === modified file 'src/emacs.c'
>> --- src/emacs.c 2014-05-27 17:31:17 +0000
>> +++ src/emacs.c 2014-05-29 12:28:19 +0000
>> @@ -2155,8 +2155,13 @@
>>    malloc_state_ptr = malloc_get_state ();
>>  #endif
>>
>> +#if defined USE_MMAP_FOR_BUFFERS && !defined WINDOWSNT
>> +  mmap_set_vars (0);
>> +#endif
>>    unexec (SSDATA (filename), !NILP (symfile) ? SSDATA (symfile) : 0);
>> -
>> +#if defined USE_MMAP_FOR_BUFFERS && !defined WINDOWSNT
>> +  mmap_set_vars (1);
>> +#endif
>>  #ifdef DOUG_LEA_MALLOC
>>    free (malloc_state_ptr);
>>  #endif
>>
>>
>> Ken
>>
>
>