linux-toradex.git/kernel, branch v3.18.20

security_syslog() should be called once only

2015-08-04T18:36:42+00:00

[ Upstream commit d194e5d666225b04c7754471df0948f645b6ab3a ]

The final version of commit 637241a900cb ("kmsg: honor dmesg_restrict
sysctl on /dev/kmsg") lost few hooks, as result security_syslog() are
processed incorrectly:

- open of /dev/kmsg checks syslog access permissions by using
  check_syslog_permissions() where security_syslog() is not called if
  dmesg_restrict is set.

- syslog syscall and /proc/kmsg calls do_syslog() where security_syslog
  can be executed twice (inside check_syslog_permissions() and then
  directly in do_syslog())

With this patch security_syslog() is called once only in all
syslog-related operations regardless of dmesg_restrict value.

Fixes: 637241a900cb ("kmsg: honor dmesg_restrict sysctl on /dev/kmsg")
Signed-off-by: Vasily Averin 
Cc: Kees Cook 
Cc: Josh Boyer 
Cc: Eric Paris 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

tracing: Have branch tracer use recursive field of task struct

2015-08-04T18:30:44+00:00

[ Upstream commit 6224beb12e190ff11f3c7d4bf50cb2922878f600 ]

Fengguang Wu's tests triggered a bug in the branch tracer's start up
test when CONFIG_DEBUG_PREEMPT set. This was because that config
adds some debug logic in the per cpu field, which calls back into
the branch tracer.

The branch tracer has its own recursive checks, but uses a per cpu
variable to implement it. If retrieving the per cpu variable calls
back into the branch tracer, you can see how things will break.

Instead of using a per cpu variable, use the trace_recursion field
of the current task struct. Simply set a bit when entering the
branch tracing and clear it when leaving. If the bit is set on
entry, just don't do the tracing.

There's also the case with lockdep, as the local_irq_save() called
before the recursion can also trigger code that can call back into
the function. Changing that to a raw_local_irq_save() will protect
that as well.

This prevents the recursion and the inevitable crash that follows.

Link: http://lkml.kernel.org/r/20150630141803.GA28071@wfg-t540p.sh.intel.com

Cc: stable@vger.kernel.org # 3.10+
Reported-by: Fengguang Wu 
Tested-by: Fengguang Wu 
Signed-off-by: Steven Rostedt 
Signed-off-by: Sasha Levin

tracing/filter: Do not WARN on operand count going below zero

2015-08-04T18:30:09+00:00

[ Upstream commit b4875bbe7e68f139bd3383828ae8e994a0df6d28 ]

When testing the fix for the trace filter, I could not come up with
a scenario where the operand count goes below zero, so I added a
WARN_ON_ONCE(cnt < 0) to the logic. But there is legitimate case
that it can happen (although the filter would be wrong).

 # echo '>' > /sys/kernel/debug/events/ext4/ext4_truncate_exit/filter

That is, a single operation without any operands will hit the path
where the WARN_ON_ONCE() can trigger. Although this is harmless,
and the filter is reported as a error. But instead of spitting out
a warning to the kernel dmesg, just fail nicely and report it via
the proper channels.

Link: http://lkml.kernel.org/r/558C6082.90608@oracle.com

Reported-by: Vince Weaver 
Reported-by: Sasha Levin 
Cc: stable@vger.kernel.org # 2.6.33+
Signed-off-by: Steven Rostedt 
Signed-off-by: Sasha Levin

perf: Fix ring_buffer_attach() RCU sync, again

2015-07-13T12:50:09+00:00

[ Upstream commit 2f993cf093643b98477c421fa2b9a98dcc940323 ]

While looking for other users of get_state/cond_sync. I Found
ring_buffer_attach() and it looks obviously buggy?

Don't we need to ensure that we have "synchronize" _between_
list_del() and list_add() ?

IOW. Suppose that ring_buffer_attach() preempts right_after
get_state_synchronize_rcu() and gp completes before spin_lock().

In this case cond_synchronize_rcu() does nothing and we reuse
->rb_entry without waiting for gp in between?

It also moves the ->rcu_pending check under "if (rb)", to make it
more readable imo.

Signed-off-by: Oleg Nesterov 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Alexander Shishkin 
Cc: Andrew Morton 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: dave@stgolabs.net
Cc: der.herr@hofr.at
Cc: josh@joshtriplett.org
Cc: tj@kernel.org
Fixes: b69cf53640da ("perf: Fix a race between ring_buffer_detach() and ring_buffer_attach()")
Link: http://lkml.kernel.org/r/20150530200425.GA15748@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

tracing: Have filter check for balanced ops

2015-07-13T12:50:03+00:00

[ Upstream commit 2cf30dc180cea808077f003c5116388183e54f9e ]

When the following filter is used it causes a warning to trigger:

 # cd /sys/kernel/debug/tracing
 # echo "((dev==1)blocks==2)" > events/ext4/ext4_truncate_exit/filter
-bash: echo: write error: Invalid argument
 # cat events/ext4/ext4_truncate_exit/filter
((dev==1)blocks==2)
^
parse_error: No error

 ------------[ cut here ]------------
 WARNING: CPU: 2 PID: 1223 at kernel/trace/trace_events_filter.c:1640 replace_preds+0x3c5/0x990()
 Modules linked in: bnep lockd grace bluetooth  ...
 CPU: 3 PID: 1223 Comm: bash Tainted: G        W       4.1.0-rc3-test+ #450
 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012
  0000000000000668 ffff8800c106bc98 ffffffff816ed4f9 ffff88011ead0cf0
  0000000000000000 ffff8800c106bcd8 ffffffff8107fb07 ffffffff8136b46c
  ffff8800c7d81d48 ffff8800d4c2bc00 ffff8800d4d4f920 00000000ffffffea
 Call Trace:
  [] dump_stack+0x4c/0x6e
  [] warn_slowpath_common+0x97/0xe0
  [] ? _kstrtoull+0x2c/0x80
  [] warn_slowpath_null+0x1a/0x20
  [] replace_preds+0x3c5/0x990
  [] create_filter+0x82/0xb0
  [] apply_event_filter+0xd4/0x180
  [] event_filter_write+0x8f/0x120
  [] __vfs_write+0x28/0xe0
  [] ? __sb_start_write+0x53/0xf0
  [] ? security_file_permission+0x30/0xc0
  [] vfs_write+0xb8/0x1b0
  [] SyS_write+0x4f/0xb0
  [] system_call_fastpath+0x12/0x6a
 ---[ end trace e11028bd95818dcd ]---

Worse yet, reading the error message (the filter again) it says that
there was no error, when there clearly was. The issue is that the
code that checks the input does not check for balanced ops. That is,
having an op between a closed parenthesis and the next token.

This would only cause a warning, and fail out before doing any real
harm, but it should still not caues a warning, and the error reported
should work:

 # cd /sys/kernel/debug/tracing
 # echo "((dev==1)blocks==2)" > events/ext4/ext4_truncate_exit/filter
-bash: echo: write error: Invalid argument
 # cat events/ext4/ext4_truncate_exit/filter
((dev==1)blocks==2)
^
parse_error: Meaningless filter expression

And give no kernel warning.

Link: http://lkml.kernel.org/r/20150615175025.7e809215@gandalf.local.home

Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Arnaldo Carvalho de Melo 
Cc: stable@vger.kernel.org # 2.6.31+
Reported-by: Vince Weaver 
Tested-by: Vince Weaver 
Signed-off-by: Steven Rostedt 
Signed-off-by: Sasha Levin

tracing/filter: Do not allow infix to exceed end of string

2015-07-05T14:12:52+00:00

[ Upstream commit 6b88f44e161b9ee2a803e5b2b1fbcf4e20e8b980 ]

While debugging a WARN_ON() for filtering, I found that it is possible
for the filter string to be referenced after its end. With the filter:

 # echo '>' > /sys/kernel/debug/events/ext4/ext4_truncate_exit/filter

The filter_parse() function can call infix_get_op() which calls
infix_advance() that updates the infix filter pointers for the cnt
and tail without checking if the filter is already at the end, which
will put the cnt to zero and the tail beyond the end. The loop then calls
infix_next() that has

	ps->infix.cnt--;
	return ps->infix.string[ps->infix.tail++];

The cnt will now be below zero, and the tail that is returned is
already passed the end of the filter string. So far the allocation
of the filter string usually has some buffer that is zeroed out, but
if the filter string is of the exact size of the allocated buffer
there's no guarantee that the charater after the nul terminating
character will be zero.

Luckily, only root can write to the filter.

Cc: stable@vger.kernel.org # 2.6.33+
Signed-off-by: Steven Rostedt 
Signed-off-by: Sasha Levin

PM / sleep: Increase default DPM watchdog timeout to 60

2015-07-05T14:12:49+00:00

[ Upstream commit fff3b16d2754a061a3549c4307a186423a0128fd ]

Many harddisks (mostly WD ones) have firmware problems and take too
long, more than 10 seconds, to resume from suspend.  And this often
exceeds the default DPM watchdog timeout (12 seconds), resulting in a
kernel panic out of sudden.

Since most distros just take the default as is, we should give a bit
more safer value.  This patch increases the default value from 12
seconds to one minute, which has been confirmed to be long enough for
such problematic disks.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=91921
Fixes: 70fea60d888d (PM / Sleep: Detect device suspend/resume lockup and log event)
Cc: 3.13+  # 3.13+
Signed-off-by: Takashi Iwai 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

rcu: Correctly handle non-empty Tiny RCU callback list with none ready

2015-07-04T03:02:21+00:00

[ Upstream commit 6e91f8cb138625be96070b778d9ba71ce520ea7e ]

If, at the time __rcu_process_callbacks() is invoked,  there are callbacks
in Tiny RCU's callback list, but none of them are ready to be invoked,
the current list-management code will knit the non-ready callbacks out
of the list.  This can result in hangs and possibly worse.  This commit
therefore inserts a check for there being no callbacks that can be
invoked immediately.

This bug is unlikely to occur -- you have to get a new callback between
the time rcu_sched_qs() or rcu_bh_qs() was called, but before we get to
__rcu_process_callbacks().  It was detected by the addition of RCU-bh
testing to rcutorture, which in turn was instigated by Iftekhar Ahmed's
mutation testing.  Although this bug was made much more likely by
915e8a4fe45e (rcu: Remove fastpath from __rcu_process_callbacks()), this
did not cause the bug, but rather made it much more probable.   That
said, it takes more than 40 hours of rcutorture testing, on average,
for this bug to appear, so this fix cannot be considered an emergency.

Signed-off-by: Paul E. McKenney 
Cc: 
Reviewed-by: Josh Triplett 
Signed-off-by: Sasha Levin

genirq: devres: Fix testing return value of request_any_context_irq()

2015-07-04T03:02:16+00:00

[ Upstream commit 63781394c540dd9e666a6b21d70b64dd52bce76e ]

request_any_context_irq() returns a negative value on failure.
It returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED on success.
So fix testing return value of request_any_context_irq().

Also fixup the return value of devm_request_any_context_irq() to make it
consistent with request_any_context_irq().

Fixes: 0668d3065128 ("genirq: Add devm_request_any_context_irq()")
Signed-off-by: Axel Lin 
Reviewed-by: Stephen Boyd 
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1431334978.17783.4.camel@ingics.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Sasha Levin

ring-buffer-benchmark: Fix the wrong sched_priority of producer

2015-07-03T16:34:40+00:00

[ Upstream commit 108029323910c5dd1ef8fa2d10da1ce5fbce6e12 ]

The producer should be used producer_fifo as its sched_priority,
so correct it.

Link: http://lkml.kernel.org/r/1433923957-67842-1-git-send-email-long.wanglong@huawei.com

Cc: stable@vger.kernel.org # 2.6.33+
Signed-off-by: Wang Long 
Signed-off-by: Steven Rostedt 
Signed-off-by: Sasha Levin