Fix: update kmem instrumentation for kernel 4.15

See upstream commit:

  commit 2d4894b5d2ae0fe1725ea7abd57b33bfbbe45492
  Author: Mel Gorman <mgorman@techsingularity.net>
  Date:   Wed Nov 15 17:37:59 2017 -0800

    mm: remove cold parameter from free_hot_cold_page*

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.9.7

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: lttng_kvmalloc helper NULL pointer OOPS

The static function __vmalloc_node is not visible by KALLSYMS_ALL on at
least some kernels, which leads to a call to a NULL function when trying
to perform allocation of lttng buffer memory under memory fragmentation
conditions (kmalloc_node failure).

Use __vmalloc_node_range instead, and check that the returned pointer
is non-NULL to ensure this type of failure does not happen in any
condition.

Fallback to __vmalloc(), even though it is not NUMA-aware, in case
we fail to find __vmalloc_node_range, and print an explicit warning
to the user console about the need to enable KALLSYMS_ALL.

This affects kernels < 4.12. Later kernels provide kvmalloc(), which
we use.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.9.6

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: lttng-logger get_user_pages_fast error handling

Comparing a signed return value against an unsigned nr_pages performs
the comparison as "unsigned", and therefore mistakenly considers
get_user_pages_fast() errors as success.

By passing an invalid pointer to write() to the /proc/lttng-logger
interface, unprivileged user-space processes can trigger a kernel OOPS.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.9.5

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update block instrumentation for 4.14 kernel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Revert "Fix: update block instrumentation for kernel 4.14"

This reverts commit 49447902967115fe5a07ee7a1df3d17fbf4b1ab8.

It introduces a NULL pointer dereference:

[ 37.862398] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
181.3  [ 37.864108] IP: [<ffffffffa01c41b7>] __event_probe__block_get_rq+0x127/0x4b0 [lttng_probe_block]
181.4  [ 37.864108] PGD 7a402067 PUD 7a4c7067 PMD 0
181.5  [ 37.864108] Oops: 0000 [#1] SMP
181.6  [ 37.864108] Modules linked in: lttng_probe_x86_exceptions(OE) lttng_probe_x86_irq_vectors(OE) lttng_probe_writeback(OE) lttng_probe_workqueue(OE) lttng_probe_vmscan(OE) lttng_probe_udp(OE) lttng_probe_timer(OE) lttng_probe_sunrpc(OE) lttng_probe_statedump(OE) lttng_probe_sock(OE) lttng_probe_skb(OE) lttng_probe_signal(OE) lttng_probe_scsi(OE) lttng_probe_sched(OE) lttng_probe_regulator(OE) lttng_probe_regmap(OE) lttng_probe_rcu(OE) lttng_probe_random(OE) lttng_probe_printk(OE) lttng_probe_power(OE) lttng_probe_net(OE) lttng_probe_napi(OE) lttng_probe_module(OE) lttng_probe_kvm_x86_mmu(OE) lttng_probe_kvm_x86(OE) lttng_probe_kvm(OE) lttng_probe_kmem(OE) lttng_probe_jbd2(OE) lttng_probe_irq(OE) lttng_probe_i2c(OE) lttng_probe_gpio(OE) lttng_probe_ext4(OE) lttng_probe_compaction(OE) lttng_probe_btrfs(OE) lttng_probe_block(OE) lttng_ring_buffer_metadata_mmap_client(OE) lttng_ring_buffer_client_mmap_overwrite(OE) lttng_ring_buffer_client_mmap_discard(OE) lttng_ring_buffer_metadata_client(OE) lttng_ring_buffer_client_overwrite(OE) lttng_ring_buffer_client_discard(OE) lttng_tracer(OE) lttng_statedump(OE) lttng_ftrace(OE) lttng_kprobes(OE) lttng_clock(OE) lttng_lib_ring_buffer(OE) lttng_kretprobes(OE)
181.7  [ 37.864108] CPU: 1 PID: 6 Comm: kworker/u4:0 Tainted: G OE 4.4.90 #1
181.8  [ 37.864108] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
181.9  [ 37.864108] Workqueue: events_freezable_power_ disk_events_workfn
181.10  [ 37.864108] task: ffff88007c861bc0 ti: ffff88007c868000 task.ti: ffff88007c868000
181.11  [ 37.864108] RIP: 0010:[<ffffffffa01c41b7>] [<ffffffffa01c41b7>] __event_probe__block_get_rq+0x127/0x4b0 [lttng_probe_block]
181.12  [ 37.864108] RSP: 0018:ffff88007c86ba98 EFLAGS: 00010246
181.13  [ 37.864108] RAX: 0000000000000000 RBX: ffff880073683348 RCX: ffff8800747d0000
181.14  [ 37.864108] RDX: 00000008d0c5bde9 RSI: 00000000000009f2 RDI: 0000000000400000
181.15  [ 37.864108] RBP: ffff88007c86bba8 R08: 00000000001789ed R09: 0000000000100000
181.16  [ 37.864108] R10: ffffe8ffffd02460 R11: 0000000000000000 R12: 0000000000000000
181.17  [ 37.864108] R13: 0000000000017fe0 R14: ffff88007363c6e8 R15: ffff88007bef83c0
181.18  [ 37.864108] FS: 0000000000000000(0000) GS:ffff88007fd00000(0000) knlGS:0000000000000000
181.19  [ 37.864108] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
181.20  [ 37.864108] CR2: 0000000000000008 CR3: 000000007a4d0000 CR4: 00000000000006e0
181.21  [ 37.864108] Stack:
181.22  [ 37.864108] 0000000000000000 ffffffff8115a46b ffff88007c86bbe8 ffff88007bc67e30
181.23  [ 37.864108] ffff880073683348 00000000ffffff01 ffff88007a7a1000 ffff88007c86bab8
181.24  [ 37.864108] 0000000000000028 0000000100000001 ffffe8ffffd02460 0000000000000035
181.25  [ 37.864108] Call Trace:
181.26  [ 37.864108] [<ffffffff8115a46b>] ? ktime_get_mono_fast_ns+0x4b/0x90
181.27  [ 37.864108] [<ffffffff81532849>] ? alloc_request_struct+0x19/0x20
181.28  [ 37.864108] [<ffffffff811e8d8f>] ? mempool_alloc+0x5f/0x150
181.29  [ 37.864108] [<ffffffffa021815c>] ? __event_probe__kmem_alloc+0x1dc/0x2c0 [lttng_probe_kmem]
181.30  [ 37.864108] [<ffffffff810ad85e>] ? kvm_clock_read+0x1e/0x20
181.31  [ 37.864108] [<ffffffff81535f4f>] get_request+0x4af/0x760
181.32  [ 37.864108] [<ffffffff8112c270>] ? wake_atomic_t_function+0x60/0x60
181.33  [ 37.864108] [<ffffffff81536283>] blk_get_request+0x83/0xe0
181.34  [ 37.864108] [<ffffffff81773b5d>] scsi_execute+0x3d/0x1d0
181.35  [ 37.864108] [<ffffffff817758fe>] scsi_execute_req_flags+0x8e/0xf0
181.36  [ 37.864108] [<ffffffff81788f4d>] sr_check_events+0x8d/0x2a0
181.37  [ 37.864108] [<ffffffff81547590>] ? disk_check_events+0x130/0x130
181.38  [ 37.864108] [<ffffffff8181b618>] cdrom_check_events+0x18/0x30
181.39  [ 37.864108] [<ffffffff8178935a>] sr_block_check_events+0x2a/0x30
181.40  [ 37.864108] [<ffffffff815474b1>] disk_check_events+0x51/0x130
181.41  [ 37.864108] [<ffffffff815475a6>] disk_events_workfn+0x16/0x20
181.42  [ 37.864108] [<ffffffff81102b85>] process_one_work+0x165/0x480
181.43  [ 37.864108] [<ffffffff81102eeb>] worker_thread+0x4b/0x4c0
181.44  [ 37.864108] [<ffffffff81102ea0>] ? process_one_work+0x480/0x480
181.45  [ 37.864108] [<ffffffff81108d86>] kthread+0xd6/0xf0
181.46  [ 37.864108] [<ffffffff81108cb0>] ? kthread_create_on_node+0x180/0x180
181.47  [ 37.864108] [<ffffffff81aa690f>] ret_from_fork+0x3f/0x70
181.48  [ 37.864108] [<ffffffff81108cb0>] ? kthread_create_on_node+0x180/0x180
181.49  [ 37.864108] Code: 00 00 00 00 48 89 85 20 ff ff ff 48 8d 85 10 ff ff ff 8b 73 04 48 89 85 28 ff ff ff 49 8b 47 48 ff 50 28 85 c0 0f 88 5d 01 00 00 <49> 8b 44 24 08 48 85 c0 0f 84 3d 03 00 00 8b 00 89 85 08 ff ff
181.50  [ 37.864108] RIP [<ffffffffa01c41b7>] __event_probe__block_get_rq+0x127/0x4b0 [lttng_probe_block]
181.51  [ 37.864108] RSP <ffff88007c86ba98>
181.52  [ 37.864108] CR2: 0000000000000008

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.9.4

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: version check error in btrfs instrumentation

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update btrfs instrumentation for kernel 4.14

See upstream commit:

  Author: Jeff Mahoney <jeffm@suse.com>
  Date:   Wed Jun 28 21:56:54 2017 -0600

    btrfs: constify tracepoint arguments

    Tracepoint arguments are all read-only.  If we mark the arguments
    as const, we're able to keep or convert those arguments to const
    where appropriate.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update writeback instrumentation for kernel 4.14

See upstream commits:

  commit 11fb998986a72aa7e997d96d63d52582a01228c5
  Author: Mel Gorman <mgorman@techsingularity.net>
  Date:   Thu Jul 28 15:46:20 2016 -0700

    mm: move most file-based accounting to the node

    There are now a number of accounting oddities such as mapped file pages
    being accounted for on the node while the total number of file pages are
    accounted on the zone.  This can be coped with to some extent but it's
    confusing so this patch moves the relevant file-based accounted.  Due to
    throttling logic in the page allocator for reliable OOM detection, it is
    still necessary to track dirty and writeback pages on a per-zone basis.

  commit c4a25635b60d08853a3e4eaae3ab34419a36cfa2
  Author: Mel Gorman <mgorman@techsingularity.net>
  Date:   Thu Jul 28 15:46:23 2016 -0700

    mm: move vmscan writes and file write accounting to the node

    As reclaim is now node-based, it follows that page write activity due to
    page reclaim should also be accounted for on the node.  For consistency,
    also account page writes and page dirtying on a per-node basis.

    After this patch, there are a few remaining zone counters that may appear
    strange but are fine.  NUMA stats are still per-zone as this is a
    user-space interface that tools consume.  NR_MLOCK, NR_SLAB_*,
    NR_PAGETABLE, NR_KERNEL_STACK and NR_BOUNCE are all allocations that
    potentially pin low memory and cannot trivially be reclaimed on demand.
    This information is still useful for debugging a page allocation failure
    warning.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update block instrumentation for kernel 4.14

See upstream commit:

  commit 74d46992e0d9dee7f1f376de0d56d31614c8a17a
  Author: Christoph Hellwig <hch@lst.de>
  Date:   Wed Aug 23 19:10:32 2017 +0200

    block: replace bi_bdev with a gendisk pointer and partitions index

    This way we don't need a block_device structure to submit I/O.  The
    block_device has different life time rules from the gendisk and
    request_queue and is usually only available when the block device node
    is open.  Other callers need to explicitly create one (e.g. the lightnvm
    passthrough code, or the new nvme multipathing code).

    For the actual I/O path all that we need is the gendisk, which exists
    once per block device.  But given that the block layer also does
    partition remapping we additionally need a partition index, which is
    used for said remapping in generic_make_request.

    Note that all the block drivers generally want request_queue or
    sometimes the gendisk, so this removes a layer of indirection all
    over the stack.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: vmalloc wrapper on kernel < 2.6.38

Ensure that all probes end up including the vmalloc wrapper through the
lttng-tracer.h header so the trace_*() static inlines are generated
through inclusion of include/trace/events/kmem.h before we define
CREATE_TRACE_POINTS.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: vmalloc wrapper on kernel >= 4.12

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add kmalloc failover to vmalloc

This patch is based on the kvmalloc helpers introduced in kernel 4.12.

It will gracefully failover memory allocations of more than one page to
vmalloc for systems under high memory pressure or fragmentation.

See Linux kernel commit:
  commit a7c3e901a46ff54c016d040847eda598a9e3e653
  Author: Michal Hocko <mhocko@suse.com>
  Date:   Mon May 8 15:57:09 2017 -0700

    mm: introduce kv[mz]alloc helpers

    Patch series "kvmalloc", v5.

    There are many open coded kmalloc with vmalloc fallback instances in the
    tree.  Most of them are not careful enough or simply do not care about
    the underlying semantic of the kmalloc/page allocator which means that
    a) some vmalloc fallbacks are basically unreachable because the kmalloc
    part will keep retrying until it succeeds b) the page allocator can
    invoke a really disruptive steps like the OOM killer to move forward
    which doesn't sound appropriate when we consider that the vmalloc
    fallback is available.

    As it can be seen implementing kvmalloc requires quite an intimate
    knowledge if the page allocator and the memory reclaim internals which
    strongly suggests that a helper should be implemented in the memory
    subsystem proper.

    Most callers, I could find, have been converted to use the helper
    instead.  This is patch 6.  There are some more relying on __GFP_REPEAT
    in the networking stack which I have converted as well and Eric Dumazet
    was not opposed [2] to convert them as well.

    [1] http://lkml.kernel.org/r/20170130094940.13546-1-mhocko@kernel.org
    [2] http://lkml.kernel.org/r/1485273626.16328.301.camel@edumazet-glaptop3.roam.corp.google.com

    This patch (of 9):

    Using kmalloc with the vmalloc fallback for larger allocations is a
    common pattern in the kernel code.  Yet we do not have any common helper
    for that and so users have invented their own helpers.  Some of them are
    really creative when doing so.  Let's just add kv[mz]alloc and make sure
    it is implemented properly.  This implementation makes sure to not make
    a large memory pressure for > PAGE_SZE requests (__GFP_NORETRY) and also
    to not warn about allocation failures.  This also rules out the OOM
    killer as the vmalloc is a more approapriate fallback than a disruptive
    user visible action.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: mmap: caches aliased on virtual addresses

Some architectures (e.g. implementations of arm64) implement their
caches based on the virtual addresses (rather than physical address).
It has the upside of making the cache access faster (no TLB lookup
required to access the cache line), but the downside of requiring
virtual mappings (e.g. kernel vs user-space) to be aligned on the number
of bits used for cache aliasing.

Perform dcache flushing for the entire sub-buffer in the get_subbuf
operation on those architectures, thus ensuring we don't end up with
cache aliasing issues.

An alternative approach we could eventually take would be to create a
kernel mapping for the ring buffer that is aligned with the user-space
mapping.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update ext4 instrumentation for kernel 4.13

See this upstream commit :

  commit a627b0a7c15ee4d2c87a86d5be5c8167382e8d0d
  Author: Eric Whitney <enwlinux@gmail.com>
  Date:   Sun Jul 30 22:30:11 2017 -0400

      ext4: remove unused metadata accounting variables

      Two variables in ext4_inode_info, i_reserved_meta_blocks and
      i_allocated_meta_blocks, are unused.  Removing them saves a little
      memory per in-memory inode and cleans up clutter in several tracepoints.
      Adjust tracepoint output from ext4_alloc_da_blocks() for consistency
      and fix a typo and whitespace near these changes.

Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Sleeping function called from invalid context

It affects system call instrumentation for accept, accept4 and connect,
only on the x86-64 architecture.

We need to use the LTTng accessing functions to touch user-space memory,
which take care of disabling the page fault handler, so we don't preempt
while in preempt-off context (tracepoints disable preemption).

Fixes #1111

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: sched for v4.11.5-rt1

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: handle missing ftrace header on v4.12

Properly handle the case where we build against the distro headers of a
kernel >= 4.12 and ftrace is enabled but the private header is
unavailable.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.9.3

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: pid tracker should track "pgid"

The "pid" notion exposed by LTTng translates to the "pgid" notion in the
Linux kernel. Therefore using "current->pid" as argument to the PID
tracker actually ends up behaving as a "tid" tracker, which does not
match the intent nor the user-space tracer behavior.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Build ftrace probe on kernels prior to 4.12

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update ftrace probe for kernel 4.12

Follow changes introduced by Linux upstream commits:
  ec19b85913486993d7d6f747beed1a711afd47d8
  bca6c8d0480a8aa5c86f8f416db96c71f6b79e29
  b5f081b563a6cdcb85a543df8c851951a8978275
  6e4443199e5354255e8a4c1e8e5cfc8ef064c3ce

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update block instrumentation for kernel 4.12

Follow changes introduced by Linux upstream commits:
  48b77ad6084481ef9330a5d2bee289966da0975b
  cee4b7ce3f9161c88f7255a3d73c1c4d5bbabea7
  caf7df12272118e0274c8353bcfeaf60c7743a47

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Add support for 4.9.27-rt18 kernel

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update btrfs instrumentation for kernel 4.12

See upstream commit 490b54d6fb75f6ffd0471ec58bb38a992e2b40cd

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update ringbuffer for kernel 4.12

flags removed from splice_pipe_desc in 4.12.

See upstream commit f81dc7d7d5a2528f98f26a0b9406e822d0b35011

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update sched instrumentation for kernel 4.12

See upstream commit b91473ff6e979c0028f02f90e40c844959c736d8

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: ext3 was completely removed from the kernel in v4.3

Don't display the warning about missing ext3 headers on kernels >= 4.3

See upstream commit e31fb9e00543e5d3c5b686747d3c862bc09b59f3

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: NULL pointer dereference of THIS_MODULE with built-in modules

THIS MODULE is defined to 0 when a module is built-in the kernel [1].
This caused NULL pointer dereference when booting a kernel with the
lttng-modules built-in.
To fix this issue, add #if guard around the wrapper_lttng_fixup_sig
function checking if the MODULE macro is defined to confirm that this
piece of code will end up in a module and not in the kernel itself.

[1]: linux/include/linux/export.h:32
Fixes: #1107
Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: add "flush empty" ioctl for stream intersection

Changing the behavior of the "snapshot" lttng command to implicitly do a
buffer "flush" (even when current packet is empty) had unwanted
side-effects: for instance, the snapshot ABI is used by the live timer
to grab the buffer positions, and we don't want to generate useless
empty packets in that scenario.

Therefore, add the "flush empty" behavior as a new ioctl to the ring
buffer. This allows lttng-tools to perform buffer flush (even for empty
packets) when it needs to. Given that this new ioctl is added within
stable branches as well, lttng-tools always need to handle "-ENOSYS"
gracefully.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Revert "Fix: flush empty packets on snapshot channel"

This reverts commit dc5cd5702b74d72f0db0141c6d888a1d820aed9c.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Revert "Fix: don't perform extra flush on metadata channel"

This reverts commit 7cf44d034bdda1896f6b0c6374c90c06d45ee4fd.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: remove CONFIG_KALLSYMS_ALL warning on clean

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.9.2

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Always build vmscan probe

The mm/vmscan.c compile unit is a obj-y, even on an old 2.6.36 kernel,
always build the vmscan probe regardless of kernel configuration.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: use of uninitialized ret value in lttng_abi_open_metadata_stream

Fixes the following compiler warning:

lttng-abi.c: In function ‘lttng_metadata_ioctl’:
lttng-abi.c:971:6: warning: ‘ret’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  int ret;
      ^

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: kref changes for kernel 4.11

The underlying type of `struct kref` changed in kernel 4.11 from an
atomic_t to a refcount_t. This change was introduced in kernel
commit:10383ae. This commit also added a builtin overflow checks to
`kref_get()` so we use it.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: atomic_add_unless() returns true/false rather than prior value

The previous implementation assumed that `atomic_add_unless` returned
the prior value of the atomic counter when in fact it returned if the
addition was performed (true) or not performed (false).
Since `atomic_add_unless` can not return INT_MAX, the `lttng_kref_get`
always returned that the call was successful.

This issue had a low likelihood of being triggered since the two refcounts
of the counters used with this call are both bounded by the maximum
number of file descriptors on the system.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: timers cputime_t arguments replaced by ull in kernel 4.11

cputime_t was changed to ull in the kernel commit: 858cf3a

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update scsi instrumentation for kernel 4.11

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: changes to the vm_op fault cb prototype in libringbuffer

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update btrfs instrumentation for kernel 4.11

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update mm_vmscan instrumentation for kernel 4.11

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: section mismatch warning caused by __exit annotation

lttng_logger_exit is used in a non-exit function so it should not be
annotated with `__exit`.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.9.1

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: nmi-safe clock on 32-bit systems

On 32-bit systems, the algorithm within lttng-modules that ensures the
nmi-safe clock increases monotonically on a CPU assumes to have one
clock read per 32-bit LSB overflow period, which is not guaranteed. It
also has an issue on the first clock reads after module load, because
the initial value for the last LSB is 0. It can cause the time to stay
stuck at the same value for a few seconds at the beginning of the trace,
which is unfortunate for the first trace after module load, because this
is where the offset between realtime and trace_clock is sampled, which
prevents correlation of kernel and user-space traces for that session.

It only affects 32-bit systems with kernels >= 3.17.

Fix this by using the non-nmi-safe clock source on 32-bit systems.

While we are there, remove an implementation-defined c99 behavior
regarding casting u64 to long by using unsigned arithmetic instead:

turn:
  if (((long) now - (long) last) < 0)
into:
  if (U64_MAX / 2 < now - last)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: only include linux/cpuhotplug.h for kernels >= 4.10

Kernels at least <= 4.4 did not have this header file.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: 4.10 hotplug adaptation backward compat

                 from /home/compudj/git/lttng-modules/lttng-context-perf-counters.c:23:
/home/compudj/git/lttng-modules/lttng-context-perf-counters.c: In function ‘lttng_add_perf_counter_to_ctx’:
/home/compudj/git/lttng-modules/lttng-context-perf-counters.c:353:22: error: ‘cpu’ undeclared (first use in this function)
  for_each_online_cpu(cpu) {
                      ^
./include/linux/cpumask.h:223:8: note: in definition of macro ‘for_each_cpu’
  for ((cpu) = -1;    \
        ^
/home/compudj/git/lttng-modules/lttng-context-perf-counters.c:353:2: note: in expansion of macro ‘for_each_online_cpu’
  for_each_online_cpu(cpu) {
  ^
/home/compudj/git/lttng-modules/lttng-context-perf-counters.c:353:22: note: each undeclared identifier is reported only once for each function it appears in
  for_each_online_cpu(cpu) {
                      ^
./include/linux/cpumask.h:223:8: note: in definition of macro ‘for_each_cpu’
  for ((cpu) = -1;    \
        ^
/home/compudj/git/lttng-modules/lttng-context-perf-counters.c:353:2: note: in expansion of macro ‘for_each_online_cpu’
  for_each_online_cpu(cpu) {
  ^
./include/linux/cpumask.h:224:38: warning: left-hand operand of comma expression has no effect [-Wunused-value]
   (cpu) = cpumask_next((cpu), (mask)), \
                                      ^
./include/linux/cpumask.h:717:36: note: in expansion of macro ‘for_each_cpu’
 #define for_each_online_cpu(cpu)   for_each_cpu((cpu), cpu_online_mask)
                                    ^
/home/compudj/git/lttng-modules/lttng-context-perf-counters.c:353:2: note: in expansion of macro ‘for_each_online_cpu’
  for_each_online_cpu(cpu) {
  ^
scripts/Makefile.build:289: recipe for target '/home/compudj/git/lttng-modules/lttng-context-perf-counters.o' failed
make[2]: *** [/home/compudj/git/lttng-modules/lttng-context-perf-counters.o] Error 1
make[2]: *** Waiting for unfinished jobs....

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Adapt lttng-modules to Linux 4.10 cpu hotplug state machine

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: 4.10 btrfs instrumentation update backward compat

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update btrfs instrumentation for 4.10 kernel

Based on commit 92a1bf76 "Btrfs: add 'inode' for extent map tracepoint"
in the upstream Linux kernel.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

btrfs instrumentation: update to 4.10 kernel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

timer instrumentation: adapt to ktime_t without union

Introduced in Linux upstream in 4.10.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: asoc instrumentation for RHEL 7.3

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: SCSI instrumentation for SLES12 SP2

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add SUSE Linux Enterprise kernel version tests

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.9.0

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Performance: add missing unlikely in reserve

Add missing branch prediction hints within lttng_event_reserve().

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: preemptible and migratable context error handling

When built against preempt-rt and preempt kernels, the "return 0" case
means success, but lttng-modules incorrectly prints an error in the
kernel log.

Given that we handle the -ENOSYS error in lttng_context_init, there is
no need to keep the ifdefs in that function.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.9.0-rc2

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: bump stable kernel version ranges for clock work-around

Linux commit 27727df240c7 ("Avoid taking lock in NMI path with
CONFIG_DEBUG_TIMEKEEPING"), changed the logic to open-code
the timekeeping_get_ns() function, but forgot to include
the unit conversion from cycles to nanoseconds, breaking the
function's output, which impacts LTTng.

We expected Linux commit 58bfea9532 "timekeeping: Fix
__ktime_get_fast_ns() regression" to make its way into stable
kernels promptly, but it appears new stable kernel releases were
done before the fix was cherry-picked from the master branch.

We therefore need to bump the version ranges for the work-around
in lttng-modules.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: John Stultz <john.stultz@linaro.org>

Version 2.9.0-rc1

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: i2c: support kernels < 3.15

i2c instrumentation has only been added in kernel 3.15.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: show warning for broken clock work-around

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Bump minor ABI version

Command added: LTTNG_KERNEL_SESSION_STATEDUMP

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: work-around upstream Linux timekeeping bug

Linux commit 27727df240c7 ("Avoid taking lock in NMI path with
CONFIG_DEBUG_TIMEKEEPING"), changed the logic to open-code
the timekeeping_get_ns() function, but forgot to include
the unit conversion from cycles to nanoseconds, breaking the
function's output, which impacts LTTng.

The following kernel versions are affected: 4.8, 4.7.4+, 4.4.20+,
4.1.32+

We expect that the upstream fix will reach the master and stable
branches timely before the next releases, so we use 4.8.1, 4.7.7,
4.4.24, and 4.1.34 as upper bounds (exclusive).

Fall-back to the non-NMI-safe trace clock for those kernel versions.
We simply discard events from NMI context with a in_nmi() check,
as we did before Linux 3.17.

Link: http://lkml.kernel.org/r/1475636148-26539-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add support for i2c tracepoints

This patch teaches lttng-modules about the i2c tracepoints in the Linux
kernel.

It contains the following tracepoints:

  * i2c_write
  * i2c_read
  * i2c_reply
  * i2c_result

I translated the fields and assignments from the kernel's
include/trace/events/i2c.h as well as I could.  I also tried building
this module against a kernel without CONFIG_I2C, and it built fine (the
required types are unconditionally defined).  So I don't think any "#if
CONFIG_I2C" or similar are required.

A module parameter (extract_sensitive_payload) controls the extraction
of possibly sensitive data from events.

[ With edit by Mathieu Desnoyers. ]

Signed-off-by: Simon Marchi <simon.marchi@ericsson.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: makefile version checks with single "ge"

Version checks in makefiles should always be a disjunctive normal form
where the conjunctions consist of one or more "equals" comparisons and
at most a single greater-or-equal comparison.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Performance: special-case NULL in lttng_strlen_user_inatomic

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: lttng_inline_memcpy does not take a __user argument

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Performance: implement lttng_inline_memcpy

Because all length parameters received for serializing data coming from
applications go through a callback, they are never constant, and it
hurts performance to perform a call to memcpy each time.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Performance: cache the backend pages pointer in context

Getting the backend pages pointer requires pointer chasing through the
ring buffer backend tables. Cache the current value so it can be re-used
for all backend write operations writing fields for the same event.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: libringbuffer: remove duplicate pointer chasing in slow paths

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Performance: Only dereference commit index once

The commit fast path should not dereference the commit counter index
repeatedly for performance reasons.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Performance: Mark channel and buffer event disabled check unlikely

Channel and buffer are typically enabled when tracing, else the probes
would not be connected. Ensure the compiler optimizes for the right
usual case.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Performance: Relax atomicity constraints for crash handling

Use a store rather than a cmpxchg() for the update of the
sequential commit counter. This speeds up commit. The downside
is that short race windows between the if() check to see if the
counter is larger than the new value and the update could result
in the counter going backwards, in unlikely preemption or signal
delivery scenarios.

Accept that we may lose a few events in a crash dump for the
benefit of tracing speed.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Performance: mark ring buffer do_copy callers always inline

The underlying copy operation is more efficient if the size is a
constant, which only happens if this function is inlined in the caller.
Otherwise, we end up calling memcpy for each field.

Force inlining for performance reasons for:
  - lib_ring_buffer_do_strcpy,
  - lib_ring_buffer_do_strcpy_from_user_inatomic,
  - lib_ring_buffer_copy_from_user_inatomic.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Performance: mark lib_ring_buffer_write always inline

The underlying copy operation is more efficient if the size is a
constant, which only happens if this function is inlined in the caller.
Otherwise, we end up calling memcpy for each field.

Force inlining for performance reasons.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Kconfig: select TRACEPOINTS when built-in

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Performance: disable event counting by default

Performance improvement changelog from lttng-ust, ported back to
lttng-modules:

Disable event counting in the ring buffer, which can count the number of
events produced per ring-buffer, as well as the number of events
overwritten in overwrite mode.

This feature is currently unused anyway: it is not saved in the ring
buffer header, nor made available to lttng-tools.

This saves 70 ns/event in lttng-ust on the ARM32 Cubietruck.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: handle large number of pages or subbuffers per buffer

Do no trigger kernel console warnings when we try to allocate too many
pages, or a too large kmalloc area for page array (within a subbuffer),
or a sub-buffer array (within a buffer).

Use vmalloc/vfree for the "pages" local variable used only during
allocation, which is an array of nr_subbuf * nr_pages_per_subbuf
pointers. This ensures we do not limit the overall buffer size due to
kmalloc limitations.

Fixes #1031

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: unregister cpu hotplug notifier on buffer alloc error

The cpu hotplug notifier needs to be unregistered in the error path of
buffer allocation, else it eventually causes kernel OOPS when the kernel
accesses freed memory of the notifier block.

Fixes #1031

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: sa_family is of type unsigned short

sa_family is an unsigned short in sockaddr definitions. For instance,
the kernel's unix_getname() function sets addrlen to sizeof(short) as it
only returns the socket's family.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: check for sizeof sa_family to save sa_family in accept and connect

The check of addrlen >= sizeof(struct sockaddr) is too restrictive
and causes sa_family to not be saved in the case of AF_UNIX sockets
as the addrlen returned by the syscall may be only sizeof(short).

Individual checks per socket family are performed anyhow in the
switch case, making this safe.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: use printk_once() for wrapper warning messages

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: btrfs instrumentation for 4.8 kernel

Note: there are missing events.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update mm_vmscan instrumentation for kernel 4.8

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: napi instrumentation for 4.8 kernels

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update block instrumentation to compile on 4.8 kernels

These 2 upstream Linux commits break the block instrumentation in lttng
modules master:

https://github.com/torvalds/linux/commit/4e1b2d52a80d79296a5d899d73249748dea71a53

https://github.com/torvalds/linux/commit/288dab8a35a0bde426a09870943c8d3ee3a50dab

The errors are :

lttng-modules/probes/../instrumentation/events/lttng-module/block.h:35:13:
error: ‘REQ_DISCARD’ undeclared (first use in this function)

lttng-modules/probes/../instrumentation/events/lttng-module/block.h:41:14:
error: ‘REQ_SECURE’ undeclared (first use in this function)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: reuse code in accept() and accept4() instrumentation

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add x86-64 override for accept4 syscall

This patch adds an instrumentation override for the accept4() syscall
which is almost identical to accept(), except for an additional
"flags" parameter.

A follow-up patch refactors both overrides to minimize code
duplication as is done for the select/pselect6 overrides.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: timer wrapper: support kernels >= 4.8

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Performance: split check deliver fast/slow paths

Performance improvement changelog from lttng-ust, ported back to
lttng-modules:

On ARMv7l (Cubietruck), the compiler generates a function call for each
lib_ring_buffer_check_deliver, even though it typically only do an
unlikely check. Split it into an inline fast path, and a function call
for the slow path. This brings a performance gain of about 500ns/event
on the Cubietruck.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: x86-64 accept instrumentation

The ipv4/ipv6 addr are output parameters.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Add support for 4.6.4-rt8 kernel

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update scsi instrumentation for 4.7+ kernels

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Use fs_initcall instead of rootfs_initcall

The rootfs_initcall for drivers built as modules was only introduced in
kernel 3.14 by commit b46d0c46ccaa366a5bb8ac709fdf2bcaa76221fd. Use
fs_initcall instead which comes just before and exists in older kernels.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>