lkml.org 
[lkml]   [2011]   [Mar]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/1] sysfs: add more info to the oops dump
Date
If we're going to remember which file we accessed, we might as well
also remember whether it was a read or a write, and if the latter,
some indication of what was written.

Changes in V2: restrict to just one line.

e.g.
$ echo sesquipedalianism > /sys/module/vt/parameters/default_utf8
$ echo c > /proc/sysrq-trigger
...
[ 57.522583] last sysfs file (w): /sys/module/vt/parameters/default_utf8 written: sesquipedaliani...(18 chars)

Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
---
fs/sysfs/file.c | 22 +++++++++++++++++++++-
1 files changed, 21 insertions(+), 1 deletions(-)

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index da3fefe..fa5b21a 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -26,9 +26,19 @@

/* used in crash dumps to help with debugging */
static char last_sysfs_file[PATH_MAX];
+static char last_sysfs_write[16];
+static int last_sysfs_write_len; /* magic value < 0 => read */
void sysfs_printk_last_file(void)
{
- printk(KERN_EMERG "last sysfs file: %s\n", last_sysfs_file);
+ printk(KERN_EMERG "last sysfs file (%c): %s%c",
+ (last_sysfs_write_len < 0) ? 'r' : 'w',
+ last_sysfs_file,
+ last_sysfs_write_len > 0 ? ' ' : '\n');
+ if (last_sysfs_write_len >= sizeof(last_sysfs_write))
+ printk(KERN_CONT " written: %s...(%d chars)\n",
+ last_sysfs_write, last_sysfs_write_len);
+ else if (last_sysfs_write_len > 0)
+ printk(KERN_CONT " written: %s\n", last_sysfs_write);
}

/*
@@ -200,12 +210,19 @@ flush_write_buffer(struct dentry * dentry, struct sysfs_buffer * buffer, size_t
struct sysfs_dirent *attr_sd = dentry->d_fsdata;
struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
const struct sysfs_ops * ops = buffer->ops;
+ int copylen = min(count, sizeof(last_sysfs_write) - 1);
int rc;

/* need attr_sd for attr and ops, its parent for kobj */
if (!sysfs_get_active(attr_sd))
return -ENODEV;

+ while (copylen > 0 && buffer->page[copylen-1] == '\n')
+ --copylen; /* never print trailing \n's */
+ memcpy(last_sysfs_write, buffer->page, copylen);
+ last_sysfs_write[copylen] = '\0';
+ last_sysfs_write_len = count;
+
rc = ops->store(kobj, attr_sd->s_attr.attr, buffer->page, count);

sysfs_put_active(attr_sd);
@@ -363,6 +380,9 @@ static int sysfs_open_file(struct inode *inode, struct file *file)
if (file->f_mode & FMODE_WRITE) {
if (!(inode->i_mode & S_IWUGO) || !ops->store)
goto err_out;
+ last_sysfs_write_len = 0;
+ } else {
+ last_sysfs_write_len = -1; /* magic value */
}

/* File needs read support.
--
1.7.2.rc1.37.gf8c40


\
 
 \ /
  Last update: 2011-03-10 22:17    [W:0.064 / U:0.268 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site