This is a note to let you know that I've just added the patch titled
/proc/stat: convert to single_open_size()
to the 3.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
proc-stat-convert-to-single_open_size.patch
and it can be found in the queue-3.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From f74373a5cc7a0155d232c4e999648c7a95435bb2 Mon Sep 17 00:00:00 2001
From: Heiko Carstens <[email protected]>
Date: Wed, 2 Jul 2014 15:22:37 -0700
Subject: /proc/stat: convert to single_open_size()
From: Heiko Carstens <[email protected]>
commit f74373a5cc7a0155d232c4e999648c7a95435bb2 upstream.
These two patches are supposed to "fix" failed order-4 memory
allocations which have been observed when reading /proc/stat. The
problem has been observed on s390 as well as on x86.
To address the problem change the seq_file memory allocations to
fallback to use vmalloc, so that allocations also work if memory is
fragmented.
This approach seems to be simpler and less intrusive than changing
/proc/stat to use an interator. Also it "fixes" other users as well,
which use seq_file's single_open() interface.
This patch (of 2):
Use seq_file's single_open_size() to preallocate a buffer that is large
enough to hold the whole output, instead of open coding it. Also
calculate the requested size using the number of online cpus instead of
possible cpus, since the size of the output only depends on the number
of online cpus.
Signed-off-by: Heiko Carstens <[email protected]>
Acked-by: David Rientjes <[email protected]>
Cc: Ian Kent <[email protected]>
Cc: Hendrik Brueckner <[email protected]>
Cc: Thorsten Diehl <[email protected]>
Cc: Andrea Righi <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Stefan Bader <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/proc/stat.c | 22 ++--------------------
1 file changed, 2 insertions(+), 20 deletions(-)
--- a/fs/proc/stat.c
+++ b/fs/proc/stat.c
@@ -184,29 +184,11 @@ static int show_stat(struct seq_file *p,
static int stat_open(struct inode *inode, struct file *file)
{
- size_t size = 1024 + 128 * num_possible_cpus();
- char *buf;
- struct seq_file *m;
- int res;
+ size_t size = 1024 + 128 * num_online_cpus();
/* minimum size to display an interrupt count : 2 bytes */
size += 2 * nr_irqs;
-
- /* don't ask for more than the kmalloc() max size */
- if (size > KMALLOC_MAX_SIZE)
- size = KMALLOC_MAX_SIZE;
- buf = kmalloc(size, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- res = single_open(file, show_stat, NULL);
- if (!res) {
- m = file->private_data;
- m->buf = buf;
- m->size = ksize(buf);
- } else
- kfree(buf);
- return res;
+ return single_open_size(file, show_stat, NULL, size);
}
static const struct file_operations proc_stat_operations = {
Patches currently in stable-queue which might be from [email protected]
are
queue-3.15/proc-stat-convert-to-single_open_size.patch
queue-3.15/fs-seq_file-fallback-to-vmalloc-allocation.patch
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