AKASHI Takahiro [Mon, 13 Jan 2014 21:33:09 +0000 (13:33 -0800)]
audit: correct a type mismatch in audit_syscall_exit()
audit_syscall_exit() saves a result of regs_return_value() in intermediate
"int" variable and passes it to __audit_syscall_exit(), which expects its
second argument as a "long" value. This will result in truncating the
value returned by a system call and making a wrong audit record.
I don't know why gcc compiler doesn't complain about this, but anyway it
causes a problem at runtime on arm64 (and probably most 64-bit archs).
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric Paris <eparis@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Eric Paris <eparis@redhat.com>
Eric Paris [Tue, 14 Jan 2014 02:16:59 +0000 (21:16 -0500)]
audit: reorder AUDIT_TTY_SET arguments
An admin is likely to want to see old and new values next to each other.
Putting all of the old values followed by all of the new values is just
hard to read as a human.
Eric Paris [Tue, 14 Jan 2014 02:12:34 +0000 (21:12 -0500)]
audit: rework AUDIT_TTY_SET to only grab spin_lock once
We can simplify the AUDIT_TTY_SET code to only grab the spin_lock one
time. We need to determine if the new values are valid and if so, set
the new values at the same time we grab the old onces. While we are
here get rid of 'res' and just use err.
Eric Paris [Mon, 13 Jan 2014 21:49:28 +0000 (16:49 -0500)]
audit: remove needless switch in AUDIT_SET
If userspace specified that it was setting values via the mask we do not
need a second check to see if they also set the version field high
enough to understand those values. (clearly if they set the mask they
knew those values).
Eric Paris [Mon, 13 Jan 2014 20:42:16 +0000 (15:42 -0500)]
audit: wait_for_auditd rework for readability
We had some craziness with signed to unsigned long casting which appears
wholely unnecessary. Just use signed long. Even though 2 values of the
math equation are unsigned longs the result is expected to be a signed
long. So why keep casting the result to signed long? Just make it
signed long and use it.
We also remove the needless "timeout" variable. We already have the
stack "sleep_time" variable. Just use that...
Gao feng [Tue, 17 Dec 2013 03:10:42 +0000 (11:10 +0800)]
audit: fix incorrect set of audit_sock
NETLINK_CB(skb).sk is the socket of user space process,
netlink_unicast in kauditd_send_skb wants the kernel
side socket. Since the sk_state of audit netlink socket
is not NETLINK_CONNECTED, so the netlink_getsockbyportid
doesn't return -ECONNREFUSED.
And the socket of userspace process can be released anytime,
so the audit_sock may point to invalid socket.
this patch sets the audit_sock to the kernel side audit
netlink socket.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Gao feng [Tue, 17 Dec 2013 03:10:41 +0000 (11:10 +0800)]
audit: print error message when fail to create audit socket
print the error message and then return -ENOMEM.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: audit_log_start running on auditd should not stop
The backlog cannot be consumed when audit_log_start is running on auditd
even if audit_log_start calls wait_for_auditd to consume it.
The situation is the deadlock because only auditd can consume the backlog.
If the other process needs to send the backlog, it can be also stopped
by the deadlock.
So, audit_log_start running on auditd should not stop.
You can see the deadlock with the following reproducer:
# auditctl -a exit,always -S all
# reboot
Signed-off-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Reviewed-by: gaofeng@cn.fujitsu.com Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: drop audit_cmd_lock in AUDIT_USER family of cases
We do not need to hold the audit_cmd_mutex for this family of cases. The
possible exception to this is the call to audit_filter_user(), so drop the lock
immediately after. To help in fixing the race we are trying to avoid, make
sure that nothing called by audit_filter_user() calls audit_log_start(). In
particular, watch out for *_audit_rule_match().
This fix will take care of systemd and anything USING audit. It still means
that we could race with something configuring audit and auditd shutting down.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Reported-by: toshi.okajima@jp.fujitsu.com Tested-by: toshi.okajima@jp.fujitsu.com Signed-off-by: Eric Paris <eparis@redhat.com>
smack: call WARN_ONCE() instead of calling audit_log_start()
Remove the call to audit_log() (which call audit_log_start()) and deal with
the errors in the caller, logging only once if the condition is met. Calling
audit_log_start() in this location makes buffer allocation and locking more
complicated in the calling tree (audit_filter_user()).
Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
selinux: call WARN_ONCE() instead of calling audit_log_start()
Two of the conditions in selinux_audit_rule_match() should never happen and
the third indicates a race that should be retried. Remove the calls to
audit_log() (which call audit_log_start()) and deal with the errors in the
caller, logging only once if the condition is met. Calling audit_log_start()
in this location makes buffer allocation and locking more complicated in the
calling tree (audit_filter_user()).
Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Paul Davies C [Thu, 21 Nov 2013 02:44:03 +0000 (08:14 +0530)]
audit: Added exe field to audit core dump signal log
Currently when the coredump signals are logged by the audit system, the
actual path to the executable is not logged. Without details of exe, the
system admin may not have an exact idea on what program failed.
This patch changes the audit_log_task() so that the path to the exe is also
logged.
This was copied from audit_log_task_info() and the latter enhanced to avoid
disappearing text fields.
Signed-off-by: Paul Davies C <pauldaviesc@gmail.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: prevent an older auditd shutdown from orphaning a newer auditd startup
There have been reports of auditd restarts resulting in kaudit not being able
to find a newly registered auditd. It results in reports such as:
kernel: [ 2077.233573] audit: *NO* daemon at audit_pid=1614
kernel: [ 2077.234712] audit: audit_lost=97 audit_rate_limit=0 audit_backlog_limit=320
kernel: [ 2077.234718] audit: auditd disappeared
(previously mis-spelled "dissapeared")
One possible cause is a race between the shutdown of an older auditd and a
newer one. If the newer one sets the daemon pid to itself in kauditd before
the older one has cleared the daemon pid, the newer daemon pid will be erased.
This could be caused by an automated system, or by manual intervention, but in
either case, there is no use in having the older daemon clear the daemon pid
reference since its old pid is no longer being referenced. This patch will
prevent that specific case, returning an error of EACCES.
The case for preventing a newer auditd from registering itself if there is an
existing auditd is a more difficult case that is beyond the scope of this
patch.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: refactor audit_receive_msg() to clarify AUDIT_*_RULE* cases
audit_receive_msg() needlessly contained a fallthrough case that called
audit_receive_filter(), containing no common code between the cases. Separate
them to make the logic clearer. Refactor AUDIT_LIST_RULES, AUDIT_ADD_RULE,
AUDIT_DEL_RULE cases to create audit_rule_change(), audit_list_rules_send()
functions. This should not functionally change the logic.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: get rid of *NO* daemon at audit_pid=0 message
kauditd_send_skb is called after audit_pid was checked to be non-zero.
However, it can be set to 0 due to auditd exiting while kauditd_send_skb
is still executed and this can result in a spurious warning about missing
auditd.
Re-check audit_pid before printing the message.
Signed-off-by: Mateusz Guzik <mguzik@redhat.com> Cc: Eric Paris <eparis@redhat.com> Cc: linux-kernel@vger.kernel.org Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Paul Davies C [Fri, 8 Nov 2013 04:27:39 +0000 (09:57 +0530)]
audit: drop audit_log_abend()
The audit_log_abend() is used only by the audit_core_dumps(). Thus there is no
need of maintaining the audit_log_abend() as a separate function.
This patch drops the audit_log_abend() and pushes its functionalities back to
the audit_core_dumps(). Apart from that the "reason" field is also dropped
from being logged since the reason can be deduced from the signal number.
Signed-off-by: Paul Davies C <pauldaviesc@gmail.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Since audit can already be disabled by "audit=0" on the kernel boot line, or by
the command "auditctl -e 0", it would be more useful to have the
audit_backlog_limit set to zero mean effectively unlimited (limited only by
system RAM).
Acked-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Gao feng [Fri, 1 Nov 2013 11:34:45 +0000 (19:34 +0800)]
audit: don't generate loginuid log when audit disabled
If audit is disabled, we shouldn't generate loginuid audit
log.
Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Gao feng [Fri, 1 Nov 2013 11:34:44 +0000 (19:34 +0800)]
audit: use old_lock in audit_set_feature
we already have old_lock, no need to calculate it again.
Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Gao feng [Fri, 1 Nov 2013 11:34:43 +0000 (19:34 +0800)]
audit: don't generate audit feature changed log when audit disabled
If audit is disabled,we shouldn't generate the audit log.
Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Gao feng [Fri, 1 Nov 2013 11:34:42 +0000 (19:34 +0800)]
audit: fix incorrect order of log new and old feature
The order of new feature and old feature is incorrect,
this patch fix it.
Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: add kernel set-up parameter to override default backlog limit
The default audit_backlog_limit is 64. This was a reasonable limit at one time.
systemd causes so much audit queue activity on startup that auditd doesn't
start before the backlog queue has already overflowed by more than a factor of
2. On a system with audit= not set on the kernel command line, this isn't an
issue since that history isn't kept for auditd when it is available. On a
system with audit=1 set on the kernel command line, kaudit tries to keep that
history until auditd is able to drain the queue.
This default can be changed by the "-b" option in audit.rules once the system
has booted, but won't help with lost messages on boot.
One way to solve this would be to increase the default backlog queue size to
avoid losing any messages before auditd is able to consume them. This would
be overkill to the embedded community and insufficient for some servers.
Another way to solve it might be to add a kconfig option to set the default
based on the system type. An embedded system would get the current (or
smaller) default, while Workstations might get more than now and servers might
get more.
None of these solutions helps if a system's compiled default is too small to
see the lost messages without compiling a new kernel.
This patch adds a kernel set-up parameter (audit already has one to
enable/disable it) "audit_backlog_limit=<n>" that overrides the default to
allow the system administrator to set the backlog limit.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Dan Duval [Mon, 16 Sep 2013 15:16:35 +0000 (11:16 -0400)]
audit: efficiency fix 2: request exclusive wait since all need same resource
These and similar errors were seen on a patched 3.8 kernel when the
audit subsystem was overrun during boot:
udevd[876]: worker [887] unexpectedly returned with status 0x0100
udevd[876]: worker [887] failed while handling
'/devices/pci0000:00/0000:00:03.0/0000:40:00.0'
udevd[876]: worker [880] unexpectedly returned with status 0x0100
udevd[876]: worker [880] failed while handling
'/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1'
udevadm settle - timeout of 180 seconds reached, the event queue
contains:
/sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1 (3995)
/sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/INT3F0D:00 (4034)
The change below increases the efficiency of the audit code and prevents it
from being overrun:
Use add_wait_queue_exclusive() in wait_for_auditd() to put the
thread on the wait queue. When kauditd dequeues an skb, all
of the waiting threads are waiting for the same resource, but
only one is going to get it, so there's no need to wake up
more than one waiter.
See: https://lkml.org/lkml/2013/9/2/479
Signed-off-by: Dan Duval <dan.duval@oracle.com> Signed-off-by: Chuck Anderson <chuck.anderson@oracle.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Dan Duval [Mon, 16 Sep 2013 15:11:12 +0000 (11:11 -0400)]
audit: efficiency fix 1: only wake up if queue shorter than backlog limit
These and similar errors were seen on a patched 3.8 kernel when the
audit subsystem was overrun during boot:
udevd[876]: worker [887] unexpectedly returned with status 0x0100
udevd[876]: worker [887] failed while handling
'/devices/pci0000:00/0000:00:03.0/0000:40:00.0'
udevd[876]: worker [880] unexpectedly returned with status 0x0100
udevd[876]: worker [880] failed while handling
'/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1'
udevadm settle - timeout of 180 seconds reached, the event queue
contains:
/sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1 (3995)
/sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/INT3F0D:00 (4034)
The change below increases the efficiency of the audit code and prevents it
from being overrun:
Only issue a wake_up in kauditd if the length of the skb queue is less than the
backlog limit. Otherwise, threads waiting in wait_for_auditd() will simply
wake up, discover that the queue is still too long for them to proceed, and go
back to sleep. This results in wasted context switches and machine cycles.
kauditd_thread() is the only function that removes buffers from audit_skb_queue
so we can't race. If we did, the timeout in wait_for_auditd() would expire and
the waiting thread would continue.
See: https://lkml.org/lkml/2013/9/2/479
Signed-off-by: Dan Duval <dan.duval@oracle.com> Signed-off-by: Chuck Anderson <chuck.anderson@oracle.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: reset audit backlog wait time after error recovery
When the audit queue overflows and times out (audit_backlog_wait_time), the
audit queue overflow timeout is set to zero. Once the audit queue overflow
timeout condition recovers, the timeout should be reset to the original value.
See also:
https://lkml.org/lkml/2013/9/2/473
Cc: stable@vger.kernel.org # v3.8-rc4+ Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Signed-off-by: Dan Duval <dan.duval@oracle.com> Signed-off-by: Chuck Anderson <chuck.anderson@oracle.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: restore order of tty and ses fields in log output
When being refactored from audit_log_start() to audit_log_task_info(), in
commit e23eb920 the tty and ses fields in the log output got transposed.
Restore to original order to avoid breaking search tools.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Normally, netlink ports use the PID of the userspace process as the port ID.
If the PID is already in use by a port, the kernel will allocate another port
ID to avoid conflict. Re-name all references to netlink ports from pid to
portid to reflect this reality and avoid confusion with actual PIDs. Ports
use the __u32 type, so re-type all portids accordingly.
(This patch is very similar to ebiederman's 5deadd69)
Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: Eric Paris <eparis@redhat.com>
- Always report the current process as capset now always only works on
the current process. This prevents reporting 0 or a random pid in
a random pid namespace.
Eric Paris [Wed, 6 Nov 2013 15:47:17 +0000 (10:47 -0500)]
audit: fix type of sessionid in audit_set_loginuid()
sfr pointed out that with CONFIG_UIDGID_STRICT_TYPE_CHECKS set the audit
tree would not build. This is because the oldsessionid in
audit_set_loginuid() was accidentally being declared as a kuid_t. This
patch fixes that declaration mistake.
Example of problem:
kernel/auditsc.c: In function 'audit_set_loginuid':
kernel/auditsc.c:2003:15: error: incompatible types when assigning to
type 'kuid_t' from type 'int'
oldsessionid = audit_get_sessionid(current);
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: call audit_bprm() only once to add AUDIT_EXECVE information
Move the audit_bprm() call from search_binary_handler() to exec_binprm(). This
allows us to get rid of the mm member of struct audit_aux_data_execve since
bprm->mm will equal current->mm.
This also mitigates the issue that ->argc could be modified by the
load_binary() call in search_binary_handler().
audit_bprm() was being called to add an AUDIT_EXECVE record to the audit
context every time search_binary_handler() was recursively called. Only one
reference is necessary.
Reported-by: Oleg Nesterov <onestero@redhat.com> Cc: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
---
This patch is against 3.11, but was developed on Oleg's post-3.11 patches that
introduce exec_binprm().
audit: move audit_aux_data_execve contents into audit_context union
audit_bprm() was being called to add an AUDIT_EXECVE record to the audit
context every time search_binary_handler() was recursively called. Only one
reference is necessary, so just update it. Move the the contents of
audit_aux_data_execve into the union in audit_context, removing dependence on a
kmalloc along the way.
Reported-by: Oleg Nesterov <onestero@redhat.com> Cc: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: Kill the unused struct audit_aux_data_capset
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
(cherry picked from ebiederman commit 6904431d6b41190e42d6b94430b67cb4e7e6a4b7) Signed-off-by: Eric Paris <eparis@redhat.com>
Eric Paris [Wed, 4 Sep 2013 19:01:43 +0000 (15:01 -0400)]
audit: do not reject all AUDIT_INODE filter types
commit ab61d38ed8cf670946d12dc46b9198b521c790ea tried to merge the
invalid filter checking into a single function. However AUDIT_INODE
filters were not verified in the new generic checker. Thus such rules
were being denied even though they were perfectly valid.
Ex:
$ auditctl -a exit,always -F arch=b64 -S open -F key=/foo -F inode=6955 -F devmajor=9 -F devminor=1
Error sending add rule data request (Invalid argument)
Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: suppress stock memalloc failure warnings since already managed
Supress the stock memory allocation failure warnings for audit buffers
since audit alreay takes care of memory allocation failure warnings, including
rate-limiting, in audit_log_start().
Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Jeff Layton [Wed, 8 May 2013 14:32:23 +0000 (10:32 -0400)]
audit: log the audit_names record type
...to make it clear what the intent behind each record's operation was.
In many cases you can infer this, based on the context of the syscall
and the result. In other cases it's not so obvious. For instance, in
the case where you have a file being renamed over another, you'll have
two different records with the same filename but different inode info.
By logging this information we can clearly tell which one was created
and which was deleted.
This fixes what was broken in commit bfcec708.
Commit 79f6530c should also be backported to stable v3.7+.
Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Jeff Layton [Wed, 8 May 2013 14:25:58 +0000 (10:25 -0400)]
audit: add child record before the create to handle case where create fails
Historically, when a syscall that creates a dentry fails, you get an audit
record that looks something like this (when trying to create a file named
"new" in "/tmp/tmp.SxiLnCcv63"):
This record makes no sense since it's associating the inode information for
"/tmp/tmp.SxiLnCcv63" with the path "/tmp/tmp.SxiLnCcv63/new". The recent
patch I posted to fix the audit_inode call in do_last fixes this, by making it
look more like this:
While this is more correct, if the creation of the file fails, then we
have no record of the filename that the user tried to create.
This patch adds a call to audit_inode_child to may_create. This creates
an AUDIT_TYPE_CHILD_CREATE record that will sit in place until the
create succeeds. When and if the create does succeed, then this record
will be updated with the correct inode info from the create.
This fixes what was broken in commit bfcec708.
Commit 79f6530c should also be backported to stable v3.7+.
Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: use nlmsg_len() to get message payload length
Using the nlmsg_len member of the netlink header to test if the message
is valid is wrong as it includes the size of the netlink header itself.
Thereby allowing to send short netlink messages that pass those checks.
Use nlmsg_len() instead to test for the right message length. The result
of nlmsg_len() is guaranteed to be non-negative as the netlink message
already passed the checks of nlmsg_ok().
Also switch to min_t() to please checkpatch.pl.
Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric Paris <eparis@redhat.com> Cc: stable@vger.kernel.org # v2.6.6+ for the 1st hunk, v2.6.23+ for the 2nd Signed-off-by: Mathias Krause <minipli@googlemail.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Eric Paris [Tue, 5 Nov 2013 15:48:02 +0000 (10:48 -0500)]
audit: use memset instead of trying to initialize field by field
We currently are setting fields to 0 to initialize the structure
declared on the stack. This is a bad idea as if the structure has holes
or unpacked space these will not be initialized. Just use memset. This
is not a performance critical section of code.
We leak 4 bytes of kernel stack in response to an AUDIT_GET request as
we miss to initialize the mask member of status_set. Fix that.
Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric Paris <eparis@redhat.com> Cc: stable@vger.kernel.org # v2.6.6+ Signed-off-by: Mathias Krause <minipli@googlemail.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Eric Paris [Thu, 23 May 2013 18:26:00 +0000 (14:26 -0400)]
audit: audit feature to set loginuid immutable
This adds a new 'audit_feature' bit which allows userspace to set it
such that the loginuid is absolutely immutable, even if you have
CAP_AUDIT_CONTROL.
Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Eric Paris [Fri, 24 May 2013 13:18:04 +0000 (09:18 -0400)]
audit: audit feature to only allow unsetting the loginuid
This is a new audit feature which only grants processes with
CAP_AUDIT_CONTROL the ability to unset their loginuid. They cannot
directly set it from a valid uid to another valid uid. The ability to
unset the loginuid is nice because a priviledged task, like that of
container creation, can unset the loginuid and then priv is not needed
inside the container when a login daemon needs to set the loginuid.
Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Eric Paris [Fri, 24 May 2013 13:49:14 +0000 (09:49 -0400)]
audit: allow unsetting the loginuid (with priv)
If a task has CAP_AUDIT_CONTROL allow that task to unset their loginuid.
This would allow a child of that task to set their loginuid without
CAP_AUDIT_CONTROL. Thus when launching a new login daemon, a
priviledged helper would be able to unset the loginuid and then the
daemon, which may be malicious user facing, do not need priv to function
correctly.
Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Eric Paris [Fri, 24 May 2013 13:39:29 +0000 (09:39 -0400)]
audit: remove CONFIG_AUDIT_LOGINUID_IMMUTABLE
After trying to use this feature in Fedora we found the hard coding
policy like this into the kernel was a bad idea. Surprise surprise.
We ran into these problems because it was impossible to launch a
container as a logged in user and run a login daemon inside that container.
This reverts back to the old behavior before this option was added. The
option will be re-added in a userspace selectable manor such that
userspace can choose when it is and when it is not appropriate.
Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Eric Paris [Fri, 24 May 2013 12:58:31 +0000 (08:58 -0400)]
audit: loginuid functions coding style
This is just a code rework. It makes things more readable. It does not
make any functional changes.
It does change the log messages to include both the old session id as
well the new and it includes a new res field, which means we get
messages even when the user did not have permission to change the
loginuid.
Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Eric Paris [Wed, 22 May 2013 16:54:49 +0000 (12:54 -0400)]
audit: implement generic feature setting and retrieving
The audit_status structure was not designed with extensibility in mind.
Define a new AUDIT_SET_FEATURE message type which takes a new structure
of bits where things can be enabled/disabled/locked one at a time. This
structure should be able to grow in the future while maintaining forward
and backward compatibility (based loosly on the ideas from capabilities
and prctl)
This does not actually add any features, but is just infrastructure to
allow new on/off types of audit system features.
Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: change decimal constant to macro for invalid uid
SFR reported this 2013-05-15:
> After merging the final tree, today's linux-next build (i386 defconfig)
> produced this warning:
>
> kernel/auditfilter.c: In function 'audit_data_to_entry':
> kernel/auditfilter.c:426:3: warning: this decimal constant is unsigned only
> in ISO C90 [enabled by default]
>
> Introduced by commit 780a7654cee8 ("audit: Make testing for a valid
> loginuid explicit") from Linus' tree.
Replace this decimal constant in the code with a macro to make it more readable
(add to the unsigned cast to quiet the warning).
Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: printk USER_AVC messages when audit isn't enabled
When the audit=1 kernel parameter is absent and auditd is not running,
AUDIT_USER_AVC messages are being silently discarded.
AUDIT_USER_AVC messages should be sent to userspace using printk(), as
mentioned in the commit message of 4a4cd633 ("AUDIT: Optimise the
audit-disabled case for discarding user messages").
When audit_enabled is 0, audit_receive_msg() discards all user messages
except for AUDIT_USER_AVC messages. However, audit_log_common_recv_msg()
refuses to allocate an audit_buffer if audit_enabled is 0. The fix is to
special case AUDIT_USER_AVC messages in both functions.
It looks like commit 50397bd1 ("[AUDIT] clean up audit_receive_msg()")
introduced this bug.
Cc: <stable@kernel.org> # v2.6.25+ Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric Paris <eparis@redhat.com> Cc: linux-audit@redhat.com Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit_alloc: clear TIF_SYSCALL_AUDIT if !audit_context
If audit_filter_task() nacks the new thread it makes sense
to clear TIF_SYSCALL_AUDIT which can be copied from parent
by dup_task_struct().
A wrong TIF_SYSCALL_AUDIT is not really bad but it triggers
the "slow" audit paths in entry.S to ensure the task can not
miss audit_syscall_*() calls, this is pointless if the task
has no ->audit_context.
Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Steve Grubb <sgrubb@redhat.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: remove newline accidentally added during session id helper refactor
A newline was accidentally added during session ID helper refactorization in
commit 4d3fb709. This needlessly uses up buffer space, messes up syslog
formatting and makes userspace processing less efficient. Remove it.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: remove duplicate inclusion of the netlink header
Signed-off-by: Ilya V. Matveychikov <matvejchikov@gmail.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
audit: format user messages to size of MAX_AUDIT_MESSAGE_LENGTH
Messages of type AUDIT_USER_TTY were being formatted to 1024 octets,
truncating messages approaching MAX_AUDIT_MESSAGE_LENGTH (8970 octets).
Set the formatting to 8560 characters, given maximum estimates for prefix and
suffix budgets.
See the problem discussion:
https://www.redhat.com/archives/linux-audit/2009-January/msg00030.html
And the new size rationale:
https://www.redhat.com/archives/linux-audit/2013-September/msg00016.html
Test ~8k messages with:
auditctl -m "$(for i in $(seq -w 001 820);do echo -n "${i}0______";done)"
Reported-by: LC Bruzenak <lenny@magitekltd.com> Reported-by: Justin Stephenson <jstephen@redhat.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Linus Torvalds [Sun, 3 Nov 2013 19:36:41 +0000 (11:36 -0800)]
Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus
Pull MIPS fixes from Ralf Baechle:
"Three fixes across arch/mips with the most complex one being the GIC
interrupt fix - at nine lines still not monster. I'm confident this
are the final MIPS patches even if there should go for an rc8"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
MIPS: ralink: fix return value check in rt_timer_probe()
MIPS: malta: Fix GIC interrupt offsets
MIPS: Perf: Fix 74K cache map
Mathias Krause [Sun, 3 Nov 2013 11:36:28 +0000 (12:36 +0100)]
ipc, msg: forbid negative values for "msg{max,mnb,mni}"
Negative message lengths make no sense -- so don't do negative queue
lenghts or identifier counts. Prevent them from getting negative.
Also change the underlying data types to be unsigned to avoid hairy
surprises with sign extensions in cases where those variables get
evaluated in unsigned expressions with bigger data types, e.g size_t.
In case a user still wants to have "unlimited" sizes she could just use
INT_MAX instead.
Vineet Gupta [Sat, 2 Nov 2013 12:17:49 +0000 (17:47 +0530)]
ARC: Incorrect mm reference used in vmalloc fault handler
A vmalloc fault needs to sync up PGD/PTE entry from init_mm to current
task's "active_mm". ARC vmalloc fault handler however was using mm.
A vmalloc fault for non user task context (actually pre-userland, from
init thread's open for /dev/console) caused the handler to deref NULL mm
(for mm->pgd)
The reasons it worked so far is amazing:
1. By default (!SMP), vmalloc fault handler uses a cached value of PGD.
In SMP that MMU register is repurposed hence need for mm pointer deref.
2. In pre-3.12 SMP kernel, the problem triggering vmalloc didn't exist in
pre-userland code path - it was introduced with commit 20bafb3d23d108bc
"n_tty: Move buffers into n_tty_data"
Ming Lei [Fri, 1 Nov 2013 22:41:33 +0000 (09:11 +1030)]
scripts/kallsyms: filter symbols not in kernel address space
This patch uses CONFIG_PAGE_OFFSET to filter symbols which
are not in kernel address space because these symbols are
generally for generating code purpose and can't be run at
kernel mode, so we needn't keep them in /proc/kallsyms.
For example, on ARM there are some symbols which may be
linked in relocatable code section, then perf can't parse
symbols any more from /proc/kallsyms, this patch fixes the
problem (introduced b9b32bf70f2fb710b07c94e13afbc729afe221da)
Cc: Russell King <linux@arm.linux.org.uk> Cc: linux-arm-kernel@lists.infradead.org Cc: Michal Marek <mmarek@suse.cz> Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: stable@vger.kernel.org
Linus Torvalds [Fri, 1 Nov 2013 19:23:56 +0000 (12:23 -0700)]
Merge tag 'usb-3.12-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
Pull USB fixes from Greg KH:
"Here is a set of patches that revert all of the changes done to the
pl2303 USB serial driver in the 3.12-rc timeframe, as it turns out
they break some devices that work just fine on 3.11. As it's not a
good idea to break working systems, drop them all and they will be
reworked for future kernel versions such that there is no breakage.
I've also included a MAINTAINERS update for the USB serial subsystem
and a new device id for the ftdi_sio driver as well"
* tag 'usb-3.12-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
USB: serial: ftdi_sio: add id for Z3X Box device
USB: Maintainers change for usb serial drivers
Revert "USB: pl2303: restrict the divisor based baud rate encoding method to the "HX" chip type"
Revert "usb: pl2303: fix+improve the divsor based baud rate encoding method"
Revert "usb: pl2303: do not round to the next nearest standard baud rate for the divisor based baud rate encoding method"
Revert "usb: pl2303: remove 500000 baud from the list of standard baud rates"
Revert "usb: pl2303: move the two baud rate encoding methods to separate functions"
Revert "usb: pl2303: increase the allowed baud rate range for the divisor based encoding method"
Revert "usb: pl2303: also use the divisor based baud rate encoding method for baud rates < 115200 with HX chips"
Revert "usb: pl2303: add two comments concerning the supported baud rates with HX chips"
Revert "pl2303: simplify the else-if contruct for type_1 chips in pl2303_startup()"
Revert "pl2303: improve the chip type information output on startup"
Revert "pl2303: improve the chip type detection/distinction"
Revert "USB: pl2303: distinguish between original and cloned HX chips"
Linus Torvalds [Fri, 1 Nov 2013 19:23:22 +0000 (12:23 -0700)]
Merge tag 'sound-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull more sound fixes from Takashi Iwai:
"The fixes for random bugs that have been reported lately in the game:
a few fixes in ASoC dpam and wm_hubs bugs spotted by Coverity, a
one-liner HD-audio fixup, and a fix for Oops with DPCM.
They are not so critically urgent bugs, but all small and safe"
* tag 'sound-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: fix oops in snd_pcm_info() caused by ASoC DPCM
ASoC: wm_hubs: Add missing break in hp_supply_event()
ALSA: hda - Add a fixup for ASUS N76VZ
ASoC: dapm: Return -ENOMEM in snd_soc_dapm_new_dai_widgets()
ASoC: dapm: Fix source list debugfs outputs
Linus Torvalds [Fri, 1 Nov 2013 19:22:47 +0000 (12:22 -0700)]
Merge tag 'clk-fixes-for-linus' of git://git.linaro.org/people/mturquette/linux
Pull clock subsystem fixes from Mike Turquette.
* tag 'clk-fixes-for-linus' of git://git.linaro.org/people/mturquette/linux:
clk: fixup argument order when setting VCO parameters
clk: socfpga: Fix incorrect sdmmc clock name
clk: armada-370: fix tclk frequencies
clk: nomadik: set all timers to use 2.4 MHz TIMCLK
Greg Thelen [Fri, 1 Nov 2013 19:16:59 +0000 (12:16 -0700)]
memcg: remove incorrect underflow check
When a memcg is deleted mem_cgroup_reparent_charges() moves charged
memory to the parent memcg. As of v3.11-9444-g3ea67d0 "memcg: add per
cgroup writeback pages accounting" there's bad pointer read. The goal
was to check for counter underflow. The counter is a per cpu counter
and there are two problems with the code:
(1) per cpu access function isn't used, instead a naked pointer is used
which easily causes oops.
(2) the check doesn't sum all cpus
The fix is to remove the check. It's currently dangerous and isn't
worth fixing it to use something expensive, such as
percpu_counter_sum(), for each reparented page. __this_cpu_read() isn't
enough to fix this because there's no guarantees of the current cpus
count. The only guarantees is that the sum of all per-cpu counter is >=
nr_pages.
Greg KH [Wed, 30 Oct 2013 18:07:31 +0000 (11:07 -0700)]
USB: Maintainers change for usb serial drivers
Johan has been conned^Wgracious in accepting the maintainership of the
USB serial drivers, especially as he's been doing all of the real work
for the past few years.
At the same time, remove a bunch of old entries for USB serial drivers
that don't make sense anymore, given that the developers are no longer
around, and individual driver maintainerships for tiny things like this
is pretty pointless.
Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip. This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip. This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip. This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip. This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip. This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip. This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip. This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip. This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip. This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip. This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip. This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip. This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Frank Schäfer <fschaefer.oss@googlemail.com> Acked-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linus Torvalds [Thu, 31 Oct 2013 23:58:23 +0000 (16:58 -0700)]
Merge branch 'akpm' (fixes from Andrew Morton)
Merge four more fixes from Andrew Morton.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
lib/scatterlist.c: don't flush_kernel_dcache_page on slab page
mm: memcg: fix test for child groups
mm: memcg: lockdep annotation for memcg OOM lock
mm: memcg: use proper memcg in limit bypass
Ming Lei [Thu, 31 Oct 2013 23:34:17 +0000 (16:34 -0700)]
lib/scatterlist.c: don't flush_kernel_dcache_page on slab page
Commit b1adaf65ba03 ("[SCSI] block: add sg buffer copy helper
functions") introduces two sg buffer copy helpers, and calls
flush_kernel_dcache_page() on pages in SG list after these pages are
written to.
Unfortunately, the commit may introduce a potential bug:
- Before sending some SCSI commands, kmalloc() buffer may be passed to
block layper, so flush_kernel_dcache_page() can see a slab page
finally
- According to cachetlb.txt, flush_kernel_dcache_page() is only called
on "a user page", which surely can't be a slab page.
- ARCH's implementation of flush_kernel_dcache_page() may use page
mapping information to do optimization so page_mapping() will see the
slab page, then VM_BUG_ON() is triggered.
Aaro Koskinen reported the bug on ARM/kirkwood when DEBUG_VM is enabled,
and this patch fixes the bug by adding test of '!PageSlab(miter->page)'
before calling flush_kernel_dcache_page().
Signed-off-by: Ming Lei <ming.lei@canonical.com> Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi> Tested-by: Simon Baatz <gmbnomis@gmail.com> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> Cc: Will Deacon <will.deacon@arm.com> Cc: Aaro Koskinen <aaro.koskinen@iki.fi> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Tejun Heo <tj@kernel.org> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: <stable@vger.kernel.org> [3.2+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Thu, 31 Oct 2013 23:34:15 +0000 (16:34 -0700)]
mm: memcg: fix test for child groups
When memcg code needs to know whether any given memcg has children, it
uses the cgroup child iteration primitives and returns true/false
depending on whether the iteration loop is executed at least once or
not.
Because a cgroup's list of children is RCU protected, these primitives
require the RCU read-lock to be held, which is not the case for all
memcg callers. This results in the following splat when e.g. enabling
hierarchy mode:
In the memcg case, we only care about children when we are attempting to
modify inheritable attributes interactively. Racing with deletion could
mean a spurious -EBUSY, no problem. Racing with addition is handled
just fine as well through the memcg_create_mutex: if the child group is
not on the list after the mutex is acquired, it won't be initialized
from the parent's attributes until after the unlock.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
projects / linux-beck.git / log