Revision 77e5bdf9f7b2d20939c8d807f3e68778d6e1557a authored by Linus Torvalds on 14 September 2016, 16:35:05 UTC, committed by Linus Torvalds on 14 September 2016, 16:35:05 UTC
Pull uaccess fixes from Al Viro: "Fixes for broken uaccess primitives - mostly lack of proper zeroing in copy_from_user()/get_user()/__get_user(), but for several architectures there's more (broken clear_user() on frv and strncpy_from_user() on hexagon)" * 'uaccess-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits) avr32: fix copy_from_user() microblaze: fix __get_user() microblaze: fix copy_from_user() m32r: fix __get_user() blackfin: fix copy_from_user() sparc32: fix copy_from_user() sh: fix copy_from_user() sh64: failing __get_user() should zero score: fix copy_from_user() and friends score: fix __get_user/get_user s390: get_user() should zero on failure ppc32: fix copy_from_user() parisc: fix copy_from_user() openrisc: fix copy_from_user() nios2: fix __get_user() nios2: copy_from_user() should zero the tail of destination mn10300: copy_from_user() should zero on access_ok() failure... mn10300: failing __get_user() and get_user() should zero mips: copy_from_user() must zero the destination on access_ok() failure ARC: uaccess: get_user to zero out dest in cause of fault ...
drop_caches.c
/*
* Implement the manual drop-all-pagecache function
*/
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/writeback.h>
#include <linux/sysctl.h>
#include <linux/gfp.h>
#include "internal.h"
/* A global variable is a bit ugly, but it keeps the code simple */
int sysctl_drop_caches;
static void drop_pagecache_sb(struct super_block *sb, void *unused)
{
struct inode *inode, *toput_inode = NULL;
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
spin_lock(&inode->i_lock);
if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
(inode->i_mapping->nrpages == 0)) {
spin_unlock(&inode->i_lock);
continue;
}
__iget(inode);
spin_unlock(&inode->i_lock);
spin_unlock(&sb->s_inode_list_lock);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
iput(toput_inode);
toput_inode = inode;
spin_lock(&sb->s_inode_list_lock);
}
spin_unlock(&sb->s_inode_list_lock);
iput(toput_inode);
}
int drop_caches_sysctl_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
{
int ret;
ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
if (ret)
return ret;
if (write) {
static int stfu;
if (sysctl_drop_caches & 1) {
iterate_supers(drop_pagecache_sb, NULL);
count_vm_event(DROP_PAGECACHE);
}
if (sysctl_drop_caches & 2) {
drop_slab();
count_vm_event(DROP_SLAB);
}
if (!stfu) {
pr_info("%s (%d): drop_caches: %d\n",
current->comm, task_pid_nr(current),
sysctl_drop_caches);
}
stfu |= sysctl_drop_caches & 4;
}
return 0;
}
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