linux-stable.git/drivers/base/core.c, branch linux-2.6.32.y

driver-core: fix race condition in get_device_parent()

2010-03-15T15:49:52+00:00

commit 77d3d7c1d561f49f755d7390f0764dff90765974 upstream.

sysfs is creating several devices in cuse class concurrently and with
CONFIG_SYSFS_DEPRECATED turned off, it triggers the following oops.

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000038
 IP: [] sysfs_addrm_start+0x4a/0xf0
 PGD 75bb067 PUD 75be067 PMD 0
 Oops: 0000 [#1] PREEMPT SMP
 last sysfs file: /sys/devices/system/cpu/cpu7/topology/core_siblings
 CPU 1
 Modules linked in: cuse fuse
 Pid: 4737, comm: osspd Not tainted 2.6.31-work #77
 RIP: 0010:[]  [] sysfs_addrm_start+0x4a/0xf0
 RSP: 0018:ffff88000042f8f8  EFLAGS: 00010296
 RAX: ffff88000042ffd8 RBX: 0000000000000000 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: ffff880007eef660 RDI: 0000000000000001
 RBP: ffff88000042f918 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000001 R11: ffffffff81158b0a R12: ffff88000042f928
 R13: 00000000fffffff4 R14: 0000000000000000 R15: ffff88000042f9a0
 FS:  00007fe93905a950(0000) GS:ffff880008600000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: 0000000000000038 CR3: 00000000077c9000 CR4: 00000000000006e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
 Process osspd (pid: 4737, threadinfo ffff88000042e000, task ffff880007eef040)
 Stack:
  ffff880005da10e8 0000000011cc8d6e ffff88000042f928 ffff880003d28a28
 <0> ffff88000042f988 ffffffff811592d7 0000000000000000 0000000000000000
 <0> 0000000000000000 0000000000000000 ffff88000042f958 0000000011cc8d6e
 Call Trace:
  [] create_dir+0x67/0xe0
  [] sysfs_create_dir+0x58/0xb0
  [] ? kobject_add_internal+0xcc/0x220
  [] ? vsnprintf+0x3c1/0xb90
  [] kobject_add_internal+0x107/0x220
  [] kobject_add_varg+0x47/0x80
  [] kobject_add+0x53/0x90
  [] device_add+0xd4/0x690
  [] ? dev_set_name+0x4b/0x70
  [] cuse_process_init_reply+0x2b4/0x420 [cuse]
  ...

The problem is that kobject_add_internal() first adds a kobject to the
kset and then try to create sysfs directory for it.  If the creation
fails, it remove the kobject from the kset.  get_device_parent()
accesses class_dirs kset while only holding class_dirs.list_lock to
see whether the cuse class dir exists.  But when it exists, it may not
have finished initialization yet or may fail and get removed soon.  In
the above case, the former happened so the second one ends up trying
to create subdirectory under NULL sysfs_dirent.

Fix it by grabbing a mutex in get_device_parent().

Signed-off-by: Tejun Heo 
Reported-by: Colin Guthrie 
Signed-off-by: Greg Kroah-Hartman

Driver core: fix race in dev_driver_string

2009-12-18T22:04:17+00:00

commit 3589972e51fac1e02d0aaa576fa47f568cb94d40 upstream.

This patch (as1310) works around a race in dev_driver_string().  If
the device is unbound while the function is running, dev->driver might
become NULL after we test it and before we dereference it.

Signed-off-by: Alan Stern 
Cc: Oliver Neukum 
Signed-off-by: Greg Kroah-Hartman

Driver-Core: extend devnode callbacks to provide permissions

2009-09-19T19:50:38+00:00

This allows subsytems to provide devtmpfs with non-default permissions
for the device node. Instead of the default mode of 0600, null, zero,
random, urandom, full, tty, ptmx now have a mode of 0666, which allows
non-privileged processes to access standard device nodes in case no
other userspace process applies the expected permissions.

This also fixes a wrong assignment in pktcdvd and a checkpatch.pl complain.

Signed-off-by: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev

2009-09-15T16:50:49+00:00

Devtmpfs lets the kernel create a tmpfs instance called devtmpfs
very early at kernel initialization, before any driver-core device
is registered. Every device with a major/minor will provide a
device node in devtmpfs.

Devtmpfs can be changed and altered by userspace at any time,
and in any way needed - just like today's udev-mounted tmpfs.
Unmodified udev versions will run just fine on top of it, and will
recognize an already existing kernel-created device node and use it.
The default node permissions are root:root 0600. Proper permissions
and user/group ownership, meaningful symlinks, all other policy still
needs to be applied by userspace.

If a node is created by devtmps, devtmpfs will remove the device node
when the device goes away. If the device node was created by
userspace, or the devtmpfs created node was replaced by userspace, it
will no longer be removed by devtmpfs.

If it is requested to auto-mount it, it makes init=/bin/sh work
without any further userspace support. /dev will be fully populated
and dynamic, and always reflect the current device state of the kernel.
With the commonly used dynamic device numbers, it solves the problem
where static devices nodes may point to the wrong devices.

It is intended to make the initial bootup logic simpler and more robust,
by de-coupling the creation of the inital environment, to reliably run
userspace processes, from a complex userspace bootstrap logic to provide
a working /dev.

Signed-off-by: Kay Sievers 
Signed-off-by: Jan Blunck 
Tested-By: Harald Hoyer 
Tested-By: Scott James Remnant 
Signed-off-by: Greg Kroah-Hartman

driver model: constify attribute groups

2009-09-15T16:50:47+00:00

Let attribute group vectors be declared "const".  We'd
like to let most attribute metadata live in read-only
sections... this is a start.

Signed-off-by: David Brownell 
Signed-off-by: Greg Kroah-Hartman

Driver core: move dev_get/set_drvdata to drivers/base/dd.c

2009-09-15T16:50:47+00:00

No one should directly access the driver_data field, so remove the field
and make it private.  We dynamically create the private field now if it
is needed, to handle drivers that call get/set before they are
registered with the driver core.

Also update the copyright notices on these files while we are there.

Cc: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

Driver core: add new device to bus's list before probing

2009-09-15T16:50:46+00:00

This patch (as1271) affects when new devices get linked into their
bus's list of devices.  Currently this happens after probing, and it
doesn't happen at all if probing fails.  Clearly this is wrong,
because at that point quite a few symbolic links have already been
created in sysfs.  We are committed to adding the device, so it should
be linked into the bus's list regardless.

In addition, this needs to happen before the uevent announcing the new
device gets issued.  Otherwise user programs might try to access the
device before it has been added to the bus.

To fix both these problems, the patch moves the call to
klist_add_tail() forward from bus_attach_device() to bus_add_device().
Since bus_attach_device() now does nothing but probe for drivers, it
has been renamed to bus_probe_device().  And lastly, the kerneldoc is
updated.

Signed-off-by: Alan Stern 
CC: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

Driver Core: add nodename callbacks

2009-06-16T04:30:25+00:00

This adds the nodename callback for struct class, struct device_type and
struct device, to allow drivers to send userspace hints on the device
name and subdirectory that should be used for it.

Signed-off-by: Kay Sievers 
Signed-off-by: Jan Blunck 
Signed-off-by: Greg Kroah-Hartman

driver core: fix gcc 4.3.3 warnings about string literals

2009-06-16T04:30:25+00:00

This removes the
	warning: format not a string literal and no format arguments
warnings in the driver core that gcc 4.3.3 complains about.

Signed-off-by: Greg Kroah-Hartman

driver core: synchronize device shutdown

2009-06-16T04:30:24+00:00

A patch series to make .shutdown execute asynchronously.  Some drivers's
shutdown can take a lot of time.  The patches can help save some shutdown
time.  The patches use Arjan's async API.


This patch:

synchronize all tasks submitted by .shutdown

Signed-off-by: Shaohua Li 
Cc: Arjan van de Ven 
Cc: Dmitry Torokhov 
Cc: James Bottomley 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman