mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-27 12:25:08 +07:00
31b4beb473
Commitc01d5b3007("shmem: get_unmapped_area align huge page") makes use of shm_get_unmapped_area() in shm_file_operations() unconditional to CONFIG_MMU. As Tony Battersby pointed this can lead NULL-pointer dereference on machine with CONFIG_MMU=y and CONFIG_SHMEM=n. In this case ipc/shm is backed by ramfs which doesn't provide f_op->get_unmapped_area for configurations with MMU. The solution is to provide dummy f_op->get_unmapped_area for ramfs when CONFIG_MMU=y, which just call current->mm->get_unmapped_area(). Fixes:c01d5b3007("shmem: get_unmapped_area align huge page") Link: http://lkml.kernel.org/r/20160912102704.140442-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Tony Battersby <tonyb@cybernetics.com> Tested-by: Tony Battersby <tonyb@cybernetics.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> [4.7.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
56 lines
1.6 KiB
C
56 lines
1.6 KiB
C
/* file-mmu.c: ramfs MMU-based file operations
|
|
*
|
|
* Resizable simple ram filesystem for Linux.
|
|
*
|
|
* Copyright (C) 2000 Linus Torvalds.
|
|
* 2000 Transmeta Corp.
|
|
*
|
|
* Usage limits added by David Gibson, Linuxcare Australia.
|
|
* This file is released under the GPL.
|
|
*/
|
|
|
|
/*
|
|
* NOTE! This filesystem is probably most useful
|
|
* not as a real filesystem, but as an example of
|
|
* how virtual filesystems can be written.
|
|
*
|
|
* It doesn't get much simpler than this. Consider
|
|
* that this file implements the full semantics of
|
|
* a POSIX-compliant read-write filesystem.
|
|
*
|
|
* Note in particular how the filesystem does not
|
|
* need to implement any data structures of its own
|
|
* to keep track of the virtual data: using the VFS
|
|
* caches is sufficient.
|
|
*/
|
|
|
|
#include <linux/fs.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/ramfs.h>
|
|
#include <linux/sched.h>
|
|
|
|
#include "internal.h"
|
|
|
|
static unsigned long ramfs_mmu_get_unmapped_area(struct file *file,
|
|
unsigned long addr, unsigned long len, unsigned long pgoff,
|
|
unsigned long flags)
|
|
{
|
|
return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
|
|
}
|
|
|
|
const struct file_operations ramfs_file_operations = {
|
|
.read_iter = generic_file_read_iter,
|
|
.write_iter = generic_file_write_iter,
|
|
.mmap = generic_file_mmap,
|
|
.fsync = noop_fsync,
|
|
.splice_read = generic_file_splice_read,
|
|
.splice_write = iter_file_splice_write,
|
|
.llseek = generic_file_llseek,
|
|
.get_unmapped_area = ramfs_mmu_get_unmapped_area,
|
|
};
|
|
|
|
const struct inode_operations ramfs_file_inode_operations = {
|
|
.setattr = simple_setattr,
|
|
.getattr = simple_getattr,
|
|
};
|