Ian Campbell [Fri, 19 Aug 2011 06:25:00 +0000 (06:25 +0000)]
net: add APIs for manipulating skb page fragments.
The primary aim is to add skb_frag_(ref|unref) in order to remove the use of
bare get/put_page on SKB pages fragments and to isolate users from subsequent
changes to the skb_frag_t data structure.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: "Michał Mirosław" <mirq-linux@rere.qmqm.pl> Cc: netdev@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
David Howells [Mon, 22 Aug 2011 13:09:36 +0000 (14:09 +0100)]
KEYS: Correctly destroy key payloads when their keytype is removed
unregister_key_type() has code to mark a key as dead and make it unavailable in
one loop and then destroy all those unavailable key payloads in the next loop.
However, the loop to mark keys dead renders the key undetectable to the second
loop by changing the key type pointer also.
Fix this by the following means:
(1) The key code has two garbage collectors: one deletes unreferenced keys and
the other alters keyrings to delete links to old dead, revoked and expired
keys. They can end up holding each other up as both want to scan the key
serial tree under spinlock. Combine these into a single routine.
(2) Move the dead key marking, dead link removal and dead key removal into the
garbage collector as a three phase process running over the three cycles
of the normal garbage collection procedure. This is tracked by the
KEY_GC_REAPING_DEAD_1, _2 and _3 state flags.
unregister_key_type() then just unlinks the key type from the list, wakes
up the garbage collector and waits for the third phase to complete.
(3) Downgrade the key types sem in unregister_key_type() once it has deleted
the key type from the list so that it doesn't block the keyctl() syscall.
(4) Dead keys that cannot be simply removed in the third phase have their
payloads destroyed with the key's semaphore write-locked to prevent
interference by the keyctl() syscall. There should be no in-kernel users
of dead keys of that type by the point of unregistration, though keyctl()
may be holding a reference.
(5) Only perform timer recalculation in the GC if the timer actually expired.
If it didn't, we'll get another cycle when it goes off - and if the key
that actually triggered it has been removed, it's not a problem.
(6) Only garbage collect link if the timer expired or if we're doing dead key
clean up phase 2.
(7) As only key_garbage_collector() is permitted to use rb_erase() on the key
serial tree, it doesn't need to revalidate its cursor after dropping the
spinlock as the node the cursor points to must still exist in the tree.
(8) Drop the spinlock in the GC if there is contention on it or if we need to
reschedule. After dealing with that, get the spinlock again and resume
scanning.
This has been tested in the following ways:
(1) Run the keyutils testsuite against it.
(2) Using the AF_RXRPC and RxKAD modules to test keytype removal:
Load the rxrpc_s key type:
# insmod /tmp/af-rxrpc.ko
# insmod /tmp/rxkad.ko
Create a key (http://people.redhat.com/~dhowells/rxrpc/listen.c):
Link it to a session keyring, preferably one with a higher serial number:
# keyctl link 0x20e36251 @s
Kill the process (the key should remain as it's linked to another place):
# fg
/tmp/listen
^C
Remove the key type:
rmmod rxkad
rmmod af-rxrpc
This can be made a more effective test by altering the following part of
the patch:
if (unlikely(gc_state & KEY_GC_REAPING_DEAD_2)) {
/* Make sure everyone revalidates their keys if we marked a
* bunch as being dead and make sure all keyring ex-payloads
* are destroyed.
*/
kdebug("dead sync");
synchronize_rcu();
To call synchronize_rcu() in GC phase 1 instead. That causes that the
keyring's old payload content to hang around longer until it's RCU
destroyed - which usually happens after GC phase 3 is complete. This
allows the destroy_dead_key branch to be tested.
Reported-by: Benjamin Coddington <bcodding@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
David Howells [Mon, 22 Aug 2011 13:09:28 +0000 (14:09 +0100)]
KEYS: The dead key link reaper should be non-reentrant
The dead key link reaper should be non-reentrant as it relies on global state
to keep track of where it's got to when it returns to the work queue manager to
give it some air.
Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
David Howells [Mon, 22 Aug 2011 13:09:20 +0000 (14:09 +0100)]
KEYS: Make the key reaper non-reentrant
Make the key reaper non-reentrant by sticking it on the appropriate system work
queue when we queue it. This will allow it to have global state and drop
locks. It should probably be non-reentrant already as it may spend a long time
holding the key serial spinlock, and so multiple entrants can spend long
periods of time just sitting there spinning, waiting to get the lock.
Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
David Howells [Mon, 22 Aug 2011 13:09:00 +0000 (14:09 +0100)]
CRED: Fix prepare_kernel_cred() to provide a new thread_group_cred struct
Fix prepare_kernel_cred() to provide a new, separate thread_group_cred struct
otherwise when using request_key() ____call_usermodehelper() calls
umh_keys_init() with the new creds pointing to init_tgcred, which
umh_keys_init() then blithely alters.
which causes the old _req keyring to go away and a new one to take its place.
This is a consequence of the changes in:
commit 879669961b11e7f40b518784863a259f735a72bf
Author: David Howells <dhowells@redhat.com>
Date: Fri Jun 17 11:25:59 2011 +0100
KEYS/DNS: Fix ____call_usermodehelper() to not lose the session keyring
and:
commit 17f60a7da150fdd0cfb9756f86a262daa72c835f
Author: Eric Paris <eparis@redhat.com>
Date: Fri Apr 1 17:07:50 2011 -0400
capabilites: allow the application of capability limits to usermode helpers
After this patch is applied, the _req keyring and the .request_key key are
cleaned up.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
David Howells [Mon, 22 Aug 2011 13:08:51 +0000 (14:08 +0100)]
KEYS: __key_link() should use the RCU deref wrapper for keyring payloads
__key_link() should use the RCU deref wrapper rcu_dereference_locked_keyring()
for accessing keyring payloads rather than calling rcu_dereference_protected()
directly.
Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
should create a session keyring if the process doesn't have one of its own
because the create flag argument is set - rather than subscribing to and
returning the user-session keyring as:
As can be seen, the session keyring starts off the same as the user-session
keyring each time, but with the patch a new session keyring is created when
the create flag is set.
Reported-by: Greg Wettstein <greg@enjellic.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Greg Wettstein <greg@enjellic.com> Signed-off-by: James Morris <jmorris@namei.org>
now always creates a new session keyring and thus the check whether the session
keyring and the user-session keyring are the same is always false. This leads
pam_keyinit to conclude that a session keyring is installed and it shouldn't be
revoked by pam_keyinit here if 'revoke' is specified.
Any system that specifies 'force' against pam_keyinit in the PAM configuration
files for login methods (login, ssh, su -l, kdm, etc.) is not affected since
that bypasses the broken check and forces the creation of a new session keyring
anyway (for which the revoke flag is not cleared) - and any subsequent call to
pam_keyinit really does have a session keyring already installed, and so the
check works correctly there.
Reverting to the previous behaviour will cause the kernel to subscribe the
process to the user-session keyring as its session keyring if it doesn't have a
session keyring of its own. pam_keyinit will detect this and install a new
session keyring anyway (and won't clear the revert flag).
This can be tested by commenting out pam_keyinit in the /etc/pam.d files and
running the following program a couple of times in a row:
As can be seen, with the patch, the session keyring is the same as the
user-session keyring each time; without the patch a new session keyring is
generated each time.
Reported-by: Greg Wettstein <greg@enjellic.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Greg Wettstein <greg@enjellic.com> Signed-off-by: James Morris <jmorris@namei.org>
Chris Boot [Mon, 22 Aug 2011 20:38:38 +0000 (21:38 +0100)]
firewire: sbp2: fix panic after rmmod with slow targets
If firewire-sbp2 starts a login to a target that doesn't complete ORBs
in a timely manner (and has to retry the login), and the module is
removed before the operation times out, you end up with a null-pointer
dereference and a kernel panic.
[SR: This happens because sbp2_target_get/put() do not maintain
module references. scsi_device_get/put() do, but at occasions like
Chris describes one, nobody holds a reference to an SBP-2 sdev.]
This patch cancels pending work for each unit in sbp2_remove(), which
hopefully means there are no extra references around that prevent us
from unloading. This fixes my crash.
Signed-off-by: Chris Boot <bootc@bootc.net> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
(
if (...) { ... when != kfree(x)
when != x = E3
when != E3 = x
* return ...;
}
... when != x = E2
when != I(...,x,...) S
if (...) { ... when != x = E4
kfree(x); ... return ...; }
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk> Acked-by: Dong Aisheng <b29396@freescale.com> Reviewed-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Liam Girdwood <lrg@ti.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Dong Aisheng [Sun, 21 Aug 2011 15:45:40 +0000 (23:45 +0800)]
ASoC: mxs-saif: clear clk gate first before register setting
Saif needs clear clk gate first before writing registers or the write
will not success.
The original xx_get_mclk function clear clk gate after mclk setting
that may cause the former mclk setting unwork, then the real output
mclk maybe inaccurate.
Placing the clear before setting mclk to avoid such an issue.
We also have to clear clk gate in startup instead of in prepare function.
Signed-off-by: Dong Aisheng <b29396@freescale.com> Acked-by: Liam Girdwood <lrg@ti.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
The first change is to add an of_node_put, since codec_np has previously
been allocated. The rest of the patch reorganizes the error handling code
so the only code executed is that which is needed.
A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)
(
if (...) { ... when != of_node_put(x)
when != x = E3
when != E3 = x
* return ...;
}
... when != x = E2
when != I(...,x,...) S
if (...) { ... when != x = E4
of_node_put(x); ... return ...; }
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk> Acked-by: Timur Tabi <timur@freescale.com> Acked-by: Liam Girdwood <lrg@ti.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
(
if (...) { ... when != of_node_put(x)
when != x = E3
when != E3 = x
* return ...;
}
... when != x = E2
when != I(...,x,...) S
if (...) { ... when != x = E4
of_node_put(x); ... return ...; }
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk> Acked-by: Liam Girdwood <lrg@ti.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
(
if (...) { ... when != kfree(x)
when != x = E3
when != E3 = x
* return ...;
}
... when != x = E2
when != I(...,x,...) S
if (...) { ... when != x = E4
kfree(x); ... return ...; }
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk> Acked-by: Alexander Sverdlin <subaparts@yandex.ru> Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com> Acked-by: Liam Girdwood <lrg@ti.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
(
if (...) { ... when != kfree(x)
when != x = E3
when != E3 = x
* return ...;
}
... when != x = E2
when != I(...,x,...) S
if (...) { ... when != x = E4
kfree(x); ... return ...; }
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk> Acked-by: Liam Girdwood <lrg@ti.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
projects / karo-tx-linux.git / log