Remove some optimizations
Signed-off-by: Paul Beeler <sparksco@gmail.com>
crypto: algif - suppress sending source address information in recvmsg

commit 72a763d805a48ac8c0bf48fdb510e84c12de51fe upstream.

The current code does not set the msg_namelen member to 0 and therefore
makes net/socket.c leak the local sockaddr_storage variable to userland
-- 128 bytes of kernel stack memory. Fix that.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
aio: fix possible invalid memory access when DEBUG is enabled

commit 91d80a84bbc8f28375cca7e65ec666577b4209ad upstream.

dprintk() shouldn't access @ring after it's unmapped.

Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: keep the second argument to kunmap_atomic()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
tracing: Use stack of calling function for stack tracer

commit 87889501d0adfae10e3b0f0e6f2d7536eed9ae84 upstream.

Use the stack of stack_trace_call() instead of check_stack() as
the test pointer for max stack size. It makes it a bit cleaner
and a little more accurate.

Adding stable, as a later fix depends on this patch.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
tracing: Fix stack tracer with fentry use

commit d4ecbfc49b4b1d4b597fb5ba9e4fa25d62f105c5 upstream.

When gcc 4.6 on x86 is used, the function tracer will use the new
option -mfentry which does a call to "fentry" at every function
instead of "mcount". The significance of this is that fentry is
called as the first operation of the function instead of the mcount
usage of being called after the stack.

This causes the stack tracer to show some bogus results for the size
of the last function traced, as well as showing "ftrace_call" instead
of the function. This is due to the stack frame not being set up
by the function that is about to be traced.

 # cat stack_trace
        Depth    Size   Location    (48 entries)
        -----    ----   --------
  0)     4824     216   ftrace_call+0x5/0x2f
  1)     4608     112   ____cache_alloc+0xb7/0x22d
  2)     4496      80   kmem_cache_alloc+0x63/0x12f

The 216 size for ftrace_call includes both the ftrace_call stack
(which includes the saving of registers it does), as well as the
stack size of the parent.

To fix this, if CC_USING_FENTRY is defined, then the stack_tracer
will reserve the first item in stack_dump_trace[] array when
calling save_stack_trace(), and it will fill it in with the parent ip.
Then the code will look for the parent pointer on the stack and
give the real size of the parent's stack pointer:

 # cat stack_trace
        Depth    Size   Location    (14 entries)
        -----    ----   --------
  0)     2640      48   update_group_power+0x26/0x187
  1)     2592     224   update_sd_lb_stats+0x2a5/0x4ac
  2)     2368     160   find_busiest_group+0x31/0x1f1
  3)     2208     256   load_balance+0xd9/0x662

I'm Cc'ing stable, although it's not urgent, as it only shows bogus
size for item #0, the rest of the trace is legit. It should still be
corrected in previous stable releases.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
tracing: Remove most or all of stack tracer stack size from stack_max_size

commit 4df297129f622bdc18935c856f42b9ddd18f9f28 upstream.

Currently, the depth reported in the stack tracer stack_trace file
does not match the stack_max_size file. This is because the stack_max_size
includes the overhead of stack tracer itself while the depth does not.

The first time a max is triggered, a calculation is not performed that
figures out the overhead of the stack tracer and subtracts it from
the stack_max_size variable. The overhead is stored and is subtracted
from the reported stack size for comparing for a new max.

Now the stack_max_size corresponds to the reported depth:

 # cat stack_max_size
4640

 # cat stack_trace
        Depth    Size   Location    (48 entries)
        -----    ----   --------
  0)     4640      32   _raw_spin_lock+0x18/0x24
  1)     4608     112   ____cache_alloc+0xb7/0x22d
  2)     4496      80   kmem_cache_alloc+0x63/0x12f
  3)     4416      16   mempool_alloc_slab+0x15/0x17
[...]

While testing against and older gcc on x86 that uses mcount instead
of fentry, I found that pasing in ip + MCOUNT_INSN_SIZE let the
stack trace show one more function deep which was missing before.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
splice: fix racy pipe->buffers uses

commit 047fe3605235888f3ebcda0c728cb31937eadfe6 upstream.

Dave Jones reported a kernel BUG at mm/slub.c:3474! triggered
by splice_shrink_spd() called from vmsplice_to_pipe()

commit 35f3d14dbbc5 (pipe: add support for shrinking and growing pipes)
added capability to adjust pipe->buffers.

Problem is some paths don't hold pipe mutex and assume pipe->buffers
doesn't change for their duration.

Fix this by adding nr_pages_max field in struct splice_pipe_desc, and
use it in place of pipe->buffers where appropriate.

splice_shrink_spd() loses its struct pipe_inode_info argument.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Tom Herbert <therbert@google.com>
Tested-by: Dave Jones <davej@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[bwh: Backported to 3.2:
 - Adjust context in vmsplice_to_pipe()
 - Update one more call to splice_shrink_spd(), from skb_splice_bits()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
trace: Add a new readonly entry to report total buffer size

The current file "buffer_size_kb" reports the size of per-cpu buffer and
not the overall memory allocated which could be misleading. A new file
"buffer_total_size_kb" adds up all the enabled CPU buffer sizes and
reports it. This is only a readonly entry.

Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: David Sharp <dhsharp@google.com>
Link: http://lkml.kernel.org/r/1313531179-9323-2-git-send-email-vnagarnaik@google.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
trace: Add ring buffer stats to measure rate of events

The stats file under per_cpu folder provides the number of entries,
overruns and other statistics about the CPU ring buffer. However, the
numbers do not provide any indication of how full the ring buffer is in
bytes compared to the overall size in bytes. Also, it is helpful to know
the rate at which the cpu buffer is filling up.

This patch adds an entry "bytes: " in printed stats for per_cpu ring
buffer which provides the actual bytes consumed in the ring buffer. This
field includes the number of bytes used by recorded events and the
padding bytes added when moving the tail pointer to next page.

It also adds the following time stamps:
"oldest event ts:" - the oldest timestamp in the ring buffer
"now ts:"  - the timestamp at the time of reading

The field "now ts" provides a consistent time snapshot to the userspace
when being read. This is read from the same trace clock used by tracing
event timestamps.

Together, these values provide the rate at which the buffer is filling
up, from the formula:
bytes / (now_ts - oldest_event_ts)

Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: David Sharp <dhsharp@google.com>
Link: http://lkml.kernel.org/r/1313531179-9323-3-git-send-email-vnagarnaik@google.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
locking, tracing: Annotate tracing locks as raw

The tracing locks can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
tracing: Add a counter clock for those that do not trust clocks

When debugging tight race conditions, it can be helpful to have a
synchronized tracing method. Although in most cases the global clock
provides this functionality, if timings is not the issue, it is more
comforting to know that the order of events really happened in a precise
order.

Instead of using a clock, add a "counter" that is simply an incrementing
atomic 64bit counter that orders the events as they are perceived to
happen.

The trace_clock_counter() is added from the attempt by Peter Zijlstra
trying to convert the trace_clock_global() to it. I took Peter's counter
code and made trace_clock_counter() instead, and added it to the choice
of clocks. Just echo counter > /debug/tracing/trace_clock to activate
it.

Requested-by: Thomas Gleixner <tglx@linutronix.de>
Requested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-By: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: Warn on output if the function tracer was found corrupted

As the function tracer is very intrusive, lots of self checks are
performed on the tracer and if something is found to be strange
it will shut itself down keeping it from corrupting the rest of the
kernel. This shutdown may still allow functions to be traced, as the
tracing only stops new modifications from happening. Trying to stop
the function tracer itself can cause more harm as it requires code
modification.

Although a WARN_ON() is executed, a user may not notice it. To help
the user see that something isn't right with the tracing of the system
a big warning is added to the output of the tracer that lets the user
know that their data may be incomplete.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: Do not allocate buffer for trace_marker

When doing intense tracing, the kmalloc inside trace_marker can
introduce side effects to what is being traced.

As trace_marker() is used by userspace to inject data into the
kernel ring buffer, it needs to do so with the least amount
of intrusion to the operations of the kernel or the user space
application.

As the ring buffer is designed to write directly into the buffer
without the need to make a temporary buffer, and userspace already
went through the hassle of knowing how big the write will be,
we can simply pin the userspace pages and write the data directly
into the buffer. This improves the impact of tracing via trace_marker
tremendously!

Thanks to Peter Zijlstra and Thomas Gleixner for pointing out the
use of get_user_pages_fast() and kmap_atomic().

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
ftrace: Fix README to state tracing_on to start/stop tracing

tracing_enabled option is deprecated.
To start/stop tracing, write to /sys/kernel/debug/tracing/tracing_on
without tracing_enabled. This patch is based on Linux 3.1.0-rc1

Signed-off-by: Geunsik Lim <geunsik.lim@samsung.com>
Link: http://lkml.kernel.org/r/1313127022-23830-1-git-send-email-leemgs1@gmail.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: Fix ftrace_dump()

commit 7fe70b579c9e3daba71635e31b6189394e7b79d3 upstream.

ftrace_dump() had a lot of issues. What ftrace_dump() does, is when
ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it
will dump out the ftrace buffers to the console when either a oops,
panic, or a sysrq-z occurs.

This was written a long time ago when ftrace was fragile to recursion.
But it wasn't written well even for that.

There's a possible deadlock that can occur if a ftrace_dump() is happening
and an NMI triggers another dump. This is because it grabs a lock
before checking if the dump ran.

It also totally disables ftrace, and tracing for no good reasons.

As the ring_buffer now checks if it is read via a oops or NMI, where
there's a chance that the buffer gets corrupted, it will disable
itself. No need to have ftrace_dump() do the same.

ftrace_dump() is now cleaned up where it uses an atomic counter to
make sure only one dump happens at a time. A simple atomic_inc_return()
is enough that is needed for both other CPUs and NMIs. No need for
a spinlock, as if one CPU is running the dump, no other CPU needs
to do it too.

The tracing_on variable is turned off and not turned on. The original
code did this, but it wasn't pretty. By just disabling this variable
we get the result of not seeing traces that happen between crashes.

For sysrq-z, it doesn't get turned on, but the user can always write
a '1' to the tracing_on file. If they are using sysrq-z, then they should
know about tracing_on.

The new code is much easier to read and less error prone. No more
deadlock possibility when an NMI triggers here.

Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
cgroup: fix an off-by-one bug which may trigger BUG_ON()

commit 3ac1707a13a3da9cfc8f242a15b2fae6df2c5f88 upstream.

The 3rd parameter of flex_array_prealloc() is the number of elements,
not the index of the last element.

The effect of the bug is, when opening cgroup.procs, a flex array will
be allocated and all elements of the array is allocated with
GFP_KERNEL flag, but the last one is GFP_ATOMIC, and if we fail to
allocate memory for it, it'll trigger a BUG_ON().

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
sysfs: fix use after free in case of concurrent read/write and readdir

commit f7db5e7660b122142410dcf36ba903c73d473250 upstream.

The inode->i_mutex isn't hold when updating filp->f_pos
in read()/write(), so the filp->f_pos might be read as
0 or 1 in readdir() when there is concurrent read()/write()
on this same file, then may cause use after free in readdir().

The bug can be reproduced with Li Zefan's test code on the
link:

	https://patchwork.kernel.org/patch/2160771/

This patch fixes the use after free under this situation.

Reported-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: file position is child inode number, not hash]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
nfsd: don't run get_file if nfs4_preprocess_stateid_op return error

commit b022032e195ffca83d7002d6b84297d796ed443b upstream.

we should return error status directly when nfs4_preprocess_stateid_op
return error.

Signed-off-by: fanchaoting <fanchaoting@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ext4/jbd2: don't wait (forever) for stale tid caused by wraparound

commit d76a3a77113db020d9bb1e894822869410450bd9 upstream.

In the case where an inode has a very stale transaction id (tid) in
i_datasync_tid or i_sync_tid, it's possible that after a very large
(2**31) number of transactions, that the tid number space might wrap,
causing tid_geq()'s calculations to fail.

Commit deeeaf13 "jbd2: fix fsync() tid wraparound bug", later modified
by commit e7b04ac0 "jbd2: don't wake kjournald unnecessarily",
attempted to fix this problem, but it only avoided kjournald spinning
forever by fixing the logic in jbd2_log_start_commit().

Unfortunately, in the codepaths in fs/ext4/fsync.c and fs/ext4/inode.c
that might call jbd2_log_start_commit() with a stale tid, those
functions will subsequently call jbd2_log_wait_commit() with the same
stale tid, and then wait for a very long time.  To fix this, we
replace the calls to jbd2_log_start_commit() and
jbd2_log_wait_commit() with a call to a new function,
jbd2_complete_transaction(), which will correctly handle stale tid's.

As a bonus, jbd2_complete_transaction() will avoid locking
j_state_lock for writing unless a commit needs to be started.  This
should have a small (but probably not measurable) improvement for
ext4's scalability.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Reported-by: George Barnett <gbarnett@atlassian.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
hrtimer: Add expiry time overflow check in hrtimer_interrupt

commit 8f294b5a139ee4b75e890ad5b443c93d1e558a8b upstream.

The settimeofday01 test in the LTP testsuite effectively does

        gettimeofday(current time);
        settimeofday(Jan 1, 1970 + 100 seconds);
        settimeofday(current time);

This test causes a stack trace to be displayed on the console during the
setting of timeofday to Jan 1, 1970 + 100 seconds:

[  131.066751] ------------[ cut here ]------------
[  131.096448] WARNING: at kernel/time/clockevents.c:209 clockevents_program_event+0x135/0x140()
[  131.104935] Hardware name: Dinar
[  131.108150] Modules linked in: sg nfsv3 nfs_acl nfsv4 auth_rpcgss nfs dns_resolver fscache lockd sunrpc nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 iptable_nat nf_nat_ipv4 nf_nat iptable_mangle ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter ip_tables kvm_amd kvm sp5100_tco bnx2 i2c_piix4 crc32c_intel k10temp fam15h_power ghash_clmulni_intel amd64_edac_mod pcspkr serio_raw edac_mce_amd edac_core microcode xfs libcrc32c sr_mod sd_mod cdrom ata_generic crc_t10dif pata_acpi radeon i2c_algo_bit drm_kms_helper ttm drm ahci pata_atiixp libahci libata usb_storage i2c_core dm_mirror dm_region_hash dm_log dm_mod
[  131.176784] Pid: 0, comm: swapper/28 Not tainted 3.8.0+ #6
[  131.182248] Call Trace:
[  131.184684]  <IRQ>  [<ffffffff810612af>] warn_slowpath_common+0x7f/0xc0
[  131.191312]  [<ffffffff8106130a>] warn_slowpath_null+0x1a/0x20
[  131.197131]  [<ffffffff810b9fd5>] clockevents_program_event+0x135/0x140
[  131.203721]  [<ffffffff810bb584>] tick_program_event+0x24/0x30
[  131.209534]  [<ffffffff81089ab1>] hrtimer_interrupt+0x131/0x230
[  131.215437]  [<ffffffff814b9600>] ? cpufreq_p4_target+0x130/0x130
[  131.221509]  [<ffffffff81619119>] smp_apic_timer_interrupt+0x69/0x99
[  131.227839]  [<ffffffff8161805d>] apic_timer_interrupt+0x6d/0x80
[  131.233816]  <EOI>  [<ffffffff81099745>] ? sched_clock_cpu+0xc5/0x120
[  131.240267]  [<ffffffff814b9ff0>] ? cpuidle_wrap_enter+0x50/0xa0
[  131.246252]  [<ffffffff814b9fe9>] ? cpuidle_wrap_enter+0x49/0xa0
[  131.252238]  [<ffffffff814ba050>] cpuidle_enter_tk+0x10/0x20
[  131.257877]  [<ffffffff814b9c89>] cpuidle_idle_call+0xa9/0x260
[  131.263692]  [<ffffffff8101c42f>] cpu_idle+0xaf/0x120
[  131.268727]  [<ffffffff815f8971>] start_secondary+0x255/0x257
[  131.274449] ---[ end trace 1151a50552231615 ]---

When we change the system time to a low value like this, the value of
timekeeper->offs_real will be a negative value.

It seems that the WARN occurs because an hrtimer has been started in the time
between the releasing of the timekeeper lock and the IPI call (via a call to
on_each_cpu) in clock_was_set() in the do_settimeofday() code.  The end result
is that a REALTIME_CLOCK timer has been added with softexpires = expires =
KTIME_MAX.  The hrtimer_interrupt() fires/is called and the loop at
kernel/hrtimer.c:1289 is executed.  In this loop the code subtracts the
clock base's offset (which was set to timekeeper->offs_real in
do_settimeofday()) from the current hrtimer_cpu_base->expiry value (which
was KTIME_MAX):

	KTIME_MAX - (a negative value) = overflow

A simple check for an overflow can resolve this problem.  Using KTIME_MAX
instead of the overflow value will result in the hrtimer function being run,
and the reprogramming of the timer after that.

Cc: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
[jstultz: Tweaked commit subject]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>