mlockall() on freebsd 7.2 + amd64 returns EAGAIN

[Sushanth Rai]

> > I don't know if that has anything to do with failure.
> The snippet of code that returns failure in vm_fault() is
> the following:
> > 
> > if (fs.pindex >= fs.object->size) {
> >   
>    unlock_and_deallocate(&fs);
> >       return
> (KERN_PROTECTION_FAILURE);
> > }
> > 
> > Any help would be appreciated.
> 
> This might be a bug fixed in r191810, but I am not sure.
> 

I tried that fix but it didn't work. What seems to happen is that libm is mmap'ed beyond the size of the file. From truss o/p, I see the following:

open("/lib/libm.so.5",O_RDONLY,030577200)	 = 3 (0x3)
fstat(3,{ mode=-r--r--r-- ,inode=918533,size=115560,blksize=4096 }) = 0 (0x0)
read(3,"\^?ELF\^B\^A\^A\t\0\0\0\0\0\0\0"...,4096) = 4096 (0x1000)
mmap(0x0,1155072,PROT_READ|PROT_EXEC,MAP_PRIVATE|MAP_NOCORE,3,0x0) = 34366242816 (0x800634000)

So the size of the file is 115560 but mmap() length is 1155072. The memory map of the file corresponding to libm as seen from running 'cat /proc/<mypid>/map' is the following:

0x800634000 0x80064c000 24 0 0xffffff002553eca8 r-x 108 54 0x0 COW NC vnode /lib/libm.so.5
0x80064c000 0x80064d000 1 0 0xffffff01d79b0a20 r-x 1 0 0x3100 COW NNC vnode /lib/libm.so.5
0x80064d000 0x80074c000 3 0 0xffffff002553eca8 r-x 108 54 0x0 COW NC vnode /lib/libm.so.5
0x80074c000 0x80074e000 2 0 0xffffff01d79f1288 rw- 1 0 0x3100 COW NNC vnode /lib/libm.so.5


when the program tries to fault-in all the pages as part of call to mlockall(), the following check in vm_fault() fails when trying to fault-in 0x800651000.

if (fs.pindex >= fs.object->size) {
     unlock_and_deallocate(&fs);
     return (KERN_PROTECTION_FAILURE);
}

since the object size corresponds to size of libm and fault address is one page beyond the object size. Is this a bug ?

Thanks,
Sushanth