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Commit 09652320 authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds
Browse files

seq_file: allocate seq_file from kmem_cache 

For fine-grained debugging and usercopy protection.

Link: http://lkml.kernel.org/r/20180310085027.GA17121@avx2


Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9ad553ab

fs/seq_file.c

+10 −2
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
 * initial implementation -- AV, Oct 2001.

 */



#include <linux/cache.h>

#include <linux/fs.h>

#include <linux/export.h>

#include <linux/seq_file.h>
@@ -19,6 +20,8 @@ 
#include <linux/uaccess.h>

#include <asm/page.h>



static struct kmem_cache *seq_file_cache __ro_after_init;



static void seq_set_overflow(struct seq_file *m)

{

	m->count = m->size;
@@ -51,7 +54,7 @@ int seq_open(struct file *file, const struct seq_operations *op) 


	WARN_ON(file->private_data);



	p = kzalloc(sizeof(*p), GFP_KERNEL);

	p = kmem_cache_zalloc(seq_file_cache, GFP_KERNEL);

	if (!p)

		return -ENOMEM;
@@ -366,7 +369,7 @@ int seq_release(struct inode *inode, struct file *file) 
{

	struct seq_file *m = file->private_data;

	kvfree(m->buf);

	kfree(m);

	kmem_cache_free(seq_file_cache, m);

	return 0;

}

EXPORT_SYMBOL(seq_release);
@@ -1106,3 +1109,8 @@ seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, 
	return NULL;

}

EXPORT_SYMBOL(seq_hlist_next_percpu);



void __init seq_file_init(void)

{

	seq_file_cache = KMEM_CACHE(seq_file, SLAB_PANIC);

}

include/linux/seq_file.h

+1 −0
Original line number Diff line number Diff line
@@ -240,4 +240,5 @@ extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *hea 


extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);



void seq_file_init(void);

#endif

init/main.c

+1 −0
Original line number Diff line number Diff line
@@ -715,6 +715,7 @@ asmlinkage __visible void __init start_kernel(void) 
	vfs_caches_init();

	pagecache_init();

	signals_init();

	seq_file_init();

	proc_root_init();

	nsfs_init();

	cpuset_init();