Re: show_uevent() and general protection fault

[Fengguang Wu]

On Mon, Jul 16, 2012 at 06:33:42PM -0700, Greg Kroah-Hartman wrote:
> On Fri, Jul 13, 2012 at 04:46:16PM +0800, Fengguang Wu wrote:
> > This is another kconfig, produced a bit different call trace, however
> > also related to sysfs_read_file().
> 
> Any hint as to which file is being read?

Good idea! I added this debugging aid:

--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -129,6 +129,11 @@ sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 {
        struct sysfs_buffer * buffer = file->private_data;
        ssize_t retval = 0;
+       char pathname[300], *path;
+
+       path = d_path(&(file->f_path), pathname, sizeof(pathname));
+       if (!IS_ERR(path))
+               printk("%s\n", path);
 
        mutex_lock(&buffer->mutex);
        if (buffer->needs_read_fill || *ppos == 0) {

And find some sysfs files that triggered the errors:

wfg@waimea ~/kvm% grep -hB1 'kernel paging request' /tmp/dmesg-kvm_bisect-waimea-*|grep /sys/               
[   28.995741] /sys/module/tpm_tis/parameters/hid
[   60.885798] /sys/module/tpm_tis/parameters/hid

wfg@waimea ~/kvm% grep -hB1 'general protection fault' /tmp/dmesg-kvm_bisect-waimea-*|grep -o /sys/.* | sort -u
/sys/devices/LNXSYSTM:00/device:00/PNP0103:00/uevent
/sys/devices/LNXSYSTM:00/device:00/PNP0A03:00/device:21/PNP0303:00/uevent
/sys/devices/LNXSYSTM:00/device:00/PNP0A03:00/device:21/PNP0400:00/uevent
/sys/devices/LNXSYSTM:00/device:00/PNP0A03:00/device:21/PNP0501:00/uevent
/sys/devices/LNXSYSTM:00/device:00/PNP0A03:00/device:21/PNP0700:00/uevent
/sys/devices/LNXSYSTM:00/device:00/PNP0A03:00/device:21/PNP0B00:00/uevent
/sys/devices/LNXSYSTM:00/device:00/PNP0A03:00/device:21/PNP0F13:00/uevent
/sys/devices/LNXSYSTM:00/device:00/PNP0A03:00/uevent
/sys/devices/LNXSYSTM:00/device:00/PNP0C0F:00/uevent
/sys/devices/LNXSYSTM:00/device:00/PNP0C0F:01/uevent
/sys/devices/LNXSYSTM:00/device:00/PNP0C0F:02/uevent
/sys/devices/LNXSYSTM:00/device:00/PNP0C0F:03/uevent
/sys/devices/LNXSYSTM:00/LNXCPU:00/uevent
/sys/devices/LNXSYSTM:00/LNXCPU:01/uevent
/sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input0/uevent
/sys/devices/LNXSYSTM:00/LNXPWRBN:00/uevent
/sys/devices/LNXSYSTM:00/uevent
/sys/devices/platform/i8042/serio0/input/input1/uevent

Thanks,
Fengguang
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