READ-ONLY mmap not present in core

READ-ONLY mmap not present in core

[Pavel Krauz]

Hi all,

I have verified that the READ_ONLY mmap mapping of file did not propagate 
to core file. For instance, if you share some file through which you exchange data
from one process to the other, you won't see it in debugger after the crash.
Is that known limitation? Can it be fixed?

best regards
Pavel

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[PATCH] Re: READ-ONLY mmap not present in core

[Pavel Krauz]

> I have verified that the READ_ONLY mmap mapping of file did not propagate 
> to core file.

Here goes a patch that solves the problem. The READ_ONLY - only mappings are now included to the core file. The executable regions are still excluded. The size of core
did not change a lot and you have all important info in core and don't get 
unreferencable pointers inside a debugger.

Please apply to 2.4.X and 2.6.X also
Pavel


with patch (emacs, netscape, xemacs):
4706304 core.all.emacs
9129984 core.all.netscape
5726208 core.all.xemacs

without patch:
4452352 core.emacs
8851456 core.netscape
5459968 core.xemacs


--- linux/fs/binfmt_elf.c.bak   Tue Oct 21 15:21:13 2003
+++ linux/fs/binfmt_elf.c       Tue Oct 21 15:21:18 2003
@@ -952,7 +952,7 @@
 #if 1
        if (vma->vm_flags & (VM_WRITE|VM_GROWSUP|VM_GROWSDOWN))
                return 1;
-       if (vma->vm_flags & (VM_READ|VM_EXEC|VM_EXECUTABLE|VM_SHARED))
+       if (vma->vm_flags & (VM_EXEC|VM_EXECUTABLE))
                return 0;
 #endif
        return 1;




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