Revision 89a8640279f8bb78aaf778d1fc5c4a6778f18064 authored by David Howells on 30 October 2009, 13:13:26 UTC, committed by Linus Torvalds on 31 October 2009, 19:11:37 UTC
Don't pass NULL pointers to fput() in the error handling paths of the NOMMU do_mmap_pgoff() as it can't handle it. The following can be used as a test program: int main() { static long long a[1024 * 1024 * 20] = { 0 }; return a;} Without the patch, the code oopses in atomic_long_dec_and_test() as called by fput() after the kernel complains that it can't allocate that big a chunk of memory. With the patch, the kernel just complains about the allocation size and then the program segfaults during execve() as execve() can't complete the allocation of all the new ELF program segments. Reported-by: Robin Getz <rgetz@blackfin.uclinux.org> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Robin Getz <rgetz@blackfin.uclinux.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 2e2ec95
extable.c
/* Rewritten by Rusty Russell, on the backs of many others...
Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/ftrace.h>
#include <linux/memory.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/init.h>
#include <asm/sections.h>
#include <asm/uaccess.h>
/*
* mutex protecting text section modification (dynamic code patching).
* some users need to sleep (allocating memory...) while they hold this lock.
*
* NOT exported to modules - patching kernel text is a really delicate matter.
*/
DEFINE_MUTEX(text_mutex);
extern struct exception_table_entry __start___ex_table[];
extern struct exception_table_entry __stop___ex_table[];
/* Sort the kernel's built-in exception table */
void __init sort_main_extable(void)
{
sort_extable(__start___ex_table, __stop___ex_table);
}
/* Given an address, look for it in the exception tables. */
const struct exception_table_entry *search_exception_tables(unsigned long addr)
{
const struct exception_table_entry *e;
e = search_extable(__start___ex_table, __stop___ex_table-1, addr);
if (!e)
e = search_module_extables(addr);
return e;
}
static inline int init_kernel_text(unsigned long addr)
{
if (addr >= (unsigned long)_sinittext &&
addr <= (unsigned long)_einittext)
return 1;
return 0;
}
int core_kernel_text(unsigned long addr)
{
if (addr >= (unsigned long)_stext &&
addr <= (unsigned long)_etext)
return 1;
if (system_state == SYSTEM_BOOTING &&
init_kernel_text(addr))
return 1;
return 0;
}
int __kernel_text_address(unsigned long addr)
{
if (core_kernel_text(addr))
return 1;
if (is_module_text_address(addr))
return 1;
/*
* There might be init symbols in saved stacktraces.
* Give those symbols a chance to be printed in
* backtraces (such as lockdep traces).
*
* Since we are after the module-symbols check, there's
* no danger of address overlap:
*/
if (init_kernel_text(addr))
return 1;
return 0;
}
int kernel_text_address(unsigned long addr)
{
if (core_kernel_text(addr))
return 1;
return is_module_text_address(addr);
}
/*
* On some architectures (PPC64, IA64) function pointers
* are actually only tokens to some data that then holds the
* real function address. As a result, to find if a function
* pointer is part of the kernel text, we need to do some
* special dereferencing first.
*/
int func_ptr_is_kernel_text(void *ptr)
{
unsigned long addr;
addr = (unsigned long) dereference_function_descriptor(ptr);
if (core_kernel_text(addr))
return 1;
return is_module_text_address(addr);
}
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