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Revision 1a512c0882bd311c5b5561840fcfbe4c25b8f319 authored by Arnd Bergmann on 24 April 2018, 21:19:51 UTC, committed by Thomas Gleixner on 27 April 2018, 15:06:29 UTC 
x86/ipc: Fix x32 version of shmid64_ds and msqid64_ds
 
A bugfix broke the x32 shmid64_ds and msqid64_ds data structure layout
(as seen from user space)  a few years ago: Originally, __BITS_PER_LONG
was defined as 64 on x32, so we did not have padding after the 64-bit
__kernel_time_t fields, After __BITS_PER_LONG got changed to 32,
applications would observe extra padding.

In other parts of the uapi headers we seem to have a mix of those
expecting either 32 or 64 on x32 applications, so we can't easily revert
the path that broke these two structures.

Instead, this patch decouples x32 from the other architectures and moves
it back into arch specific headers, partially reverting the even older
commit 73a2d096fdf2 ("x86: remove all now-duplicate header files").

It's not clear whether this ever made any difference, since at least
glibc carries its own (correct) copy of both of these header files,
so possibly no application has ever observed the definitions here.

Based on a suggestion from H.J. Lu, I tried out the tool from
https://github.com/hjl-tools/linux-header to find other such
bugs, which pointed out the same bug in statfs(), which also has
a separate (correct) copy in glibc.

Fixes: f4b4aae18288 ("x86/headers/uapi: Fix __BITS_PER_LONG value for x32 builds")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H . J . Lu" <hjl.tools@gmail.com>
Cc: Jeffrey Walton <noloader@gmail.com>
Cc: stable@vger.kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20180424212013.3967461-1-arnd@arndb.de
1 parent 3db3eb2
Raw File
interval_tree.c 
/*
 * mm/interval_tree.c - interval tree for mapping->i_mmap
 *
 * Copyright (C) 2012, Michel Lespinasse <walken@google.com>
 *
 * This file is released under the GPL v2.
 */

#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/rmap.h>
#include <linux/interval_tree_generic.h>

static inline unsigned long vma_start_pgoff(struct vm_area_struct *v)
{
	return v->vm_pgoff;
}

static inline unsigned long vma_last_pgoff(struct vm_area_struct *v)
{
	return v->vm_pgoff + vma_pages(v) - 1;
}

INTERVAL_TREE_DEFINE(struct vm_area_struct, shared.rb,
		     unsigned long, shared.rb_subtree_last,
		     vma_start_pgoff, vma_last_pgoff,, vma_interval_tree)

/* Insert node immediately after prev in the interval tree */
void vma_interval_tree_insert_after(struct vm_area_struct *node,
				    struct vm_area_struct *prev,
				    struct rb_root_cached *root)
{
	struct rb_node **link;
	struct vm_area_struct *parent;
	unsigned long last = vma_last_pgoff(node);

	VM_BUG_ON_VMA(vma_start_pgoff(node) != vma_start_pgoff(prev), node);

	if (!prev->shared.rb.rb_right) {
		parent = prev;
		link = &prev->shared.rb.rb_right;
	} else {
		parent = rb_entry(prev->shared.rb.rb_right,
				  struct vm_area_struct, shared.rb);
		if (parent->shared.rb_subtree_last < last)
			parent->shared.rb_subtree_last = last;
		while (parent->shared.rb.rb_left) {
			parent = rb_entry(parent->shared.rb.rb_left,
				struct vm_area_struct, shared.rb);
			if (parent->shared.rb_subtree_last < last)
				parent->shared.rb_subtree_last = last;
		}
		link = &parent->shared.rb.rb_left;
	}

	node->shared.rb_subtree_last = last;
	rb_link_node(&node->shared.rb, &parent->shared.rb, link);
	rb_insert_augmented(&node->shared.rb, &root->rb_root,
			    &vma_interval_tree_augment);
}

static inline unsigned long avc_start_pgoff(struct anon_vma_chain *avc)
{
	return vma_start_pgoff(avc->vma);
}

static inline unsigned long avc_last_pgoff(struct anon_vma_chain *avc)
{
	return vma_last_pgoff(avc->vma);
}

INTERVAL_TREE_DEFINE(struct anon_vma_chain, rb, unsigned long, rb_subtree_last,
		     avc_start_pgoff, avc_last_pgoff,
		     static inline, __anon_vma_interval_tree)

void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
				   struct rb_root_cached *root)
{
#ifdef CONFIG_DEBUG_VM_RB
	node->cached_vma_start = avc_start_pgoff(node);
	node->cached_vma_last = avc_last_pgoff(node);
#endif
	__anon_vma_interval_tree_insert(node, root);
}

void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
				   struct rb_root_cached *root)
{
	__anon_vma_interval_tree_remove(node, root);
}

struct anon_vma_chain *
anon_vma_interval_tree_iter_first(struct rb_root_cached *root,
				  unsigned long first, unsigned long last)
{
	return __anon_vma_interval_tree_iter_first(root, first, last);
}

struct anon_vma_chain *
anon_vma_interval_tree_iter_next(struct anon_vma_chain *node,
				 unsigned long first, unsigned long last)
{
	return __anon_vma_interval_tree_iter_next(node, first, last);
}

#ifdef CONFIG_DEBUG_VM_RB
void anon_vma_interval_tree_verify(struct anon_vma_chain *node)
{
	WARN_ON_ONCE(node->cached_vma_start != avc_start_pgoff(node));
	WARN_ON_ONCE(node->cached_vma_last != avc_last_pgoff(node));
}
#endif
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