Document limitation of vppid and ppid context wrt eventual RCU instrumentation

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

Cleanup: no need to hold RCU read-side lock when reading current nsproxy

As documented in include/linux/nsproxy.h.

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

Add env hostname information

Approximation in case of hostname change or in case of
contextualisation, but it does the job for 95% of use-cases.

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

Fix: lttng_statedump_process_state for each PID NS has infinite loop

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

lttng_statedump_process_state for each PID NS

When a process is in a namespace, its pid, tid and ppid are relative to
the namespace. Since namespaces can be nested, we need to know the
representation of each process in each namespace.

This patch changes the lttng_enumerate_task_fd to iterate over each
PID namespace of a process if any, that way we generate, in the
statedump, an entry for each process in each namespace it belongs.
To know the nesting level, the field "level" is added to the
lttng_statedump_process_state event, 0 being the top-level.
For processes running on the top-level namespace, the statedump
behaviour is unchanged (except the added "level" field).

For example (no nesting, just one level of namespace) :
lttng_statedump_process_state: {
        tid = 32185, vtid = 1, pid = 32185,
        vpid = 1, ppid = 32173, vppid = 0,
        level = 1, name = "init" }
lttng_statedump_process_state: {
        tid = 32185, vtid = 32185, pid = 32185,
        vpid = 32185, ppid = 32173, vppid = 32173,
        level = 0, name = "init" }

Confirmed that the process 32173 in the top-level namespace is indeed
the lxc-start command that created the container and its namespace.

[ Edit by Mathieu Desnoyers: Minor cleanups ]

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

Support the hostname context

This is particularly useful when tracing a machine with containers
(lxc), that way we can easily distinguish events generated inside
a container.

[ Edit by Mathieu Desnoyers: various fix. ]

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

Fix: statedump namespaced pid, tid and ppid

Use the target process namespace to lookup the value (pid, tid or ppid),
not the current task.

[ Edit by Mathieu Desnoyers: removed extra p->nsproxy check. Already
  performed within rcu read-side critical section. ]

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

Fix: statedump: disable vm maps enumeration

We need the tasklist lock to correctly dump these, which is unavailable
to modules. Disable this feature for now.

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

Fix: ensure userspace accesses are done with _inatomic

Otherwise, triggers scheduling while atomic (might_sleep()) warnings,
since we call those from a tracepoint probe (with preemption disabled).

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

Fix: vppid context should test for current nsproxy

Triggers a NULL pointer exception with tracing scheduling events with
vppid context activated.

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

Add MIPS system call support

[ Edit by Mathieu: currently missing: update of arch-independent headers
  to include the MIPS headers to complete system call support. ]

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Change mode of lttng-syscalls-generate-headers.sh to 755

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

cleanup: fix typo in syscall instrumentation header

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: remove trailing whitespace in README

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

trace event: introduce TP_MODULE_NOAUTOLOAD and TP_MODULE_NOINIT

In preparation for introducing uevent tracing. (user-space events)

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

LTTng: probe-statedump: add #include <linux/sched.h>

This fixes the following build error on ARM;

  CC [M]  drivers/staging/lttng/probes/lttng-probe-statedump.o
In file included from drivers/staging/lttng/probes/../instrumentation/events/lttng-module/../../../probes/lttng-events.h:221:0,
                 from drivers/staging/lttng/probes/../instrumentation/events/lttng-module/../../../probes/define_trace.h:117,
                 from drivers/staging/lttng/probes/../instrumentation/events/lttng-module/lttng-statedump.h:162,
                 from drivers/staging/lttng/probes/lttng-probe-statedump.c:41:
drivers/staging/lttng/probes/../instrumentation/events/lttng-module/../../../probes/../instrumentation/events/lttng-module/lttng-statedump.h:29:1: error: 'TASK_COMM_LEN' undeclared here (not in a function)

Signed-off-by: UCHINO Satoshi <satoshi.uchino@toshiba.co.jp>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

fix: signal_generate event should print utf8 for comm field

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

Makes write operation a parameter for tp_memcpy macro

Memcpy source can be either user-space or kernel-space. To avoid code
duplication, this patch makes the operation a parameter to the macros.
Available macros are thus:

* tp_memcpy:               kernel-space array copy
* tp_memcpy_from_user:     user-space array copy
* tp_memcpy_dyn:           kernel-space sequence copy
* tp_memcpy_dyn_from_user: user-space sequence copy

Those are TP_fast_assign macros that can be used with __dynamic_array
macros in TP_STRUCT__entry in a TRACE_EVENT.

Signed-off-by: Francis Giraldeau <francis.giraldeau@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add coding style document

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

Update instrumentation/events README file

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

Add makefile target for preprocessor

By specifying .i target, it runs gcc preprocessor for that file.
Example:

  make myfile.i

will read myfile.c and output preprocessor to myfile.i

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

Fix: free_event_id check should compare unsigned int with -1U

Otherwise, on 32-bit:

lttng-modules/lttng-events.c:295: warning: comparison is always false due
to limited range of data type

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

Use unsigned long type for events discarded counter

Overflows at 64-bit on 64-bit systems.

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

Fix: update signal instrumentation for 3.4 kernel

Fix #226

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

LTTng Modules ARM syscall instrumentation

This patch adds detailed instrumentation for ARM system calls, based on
a 2.6.38 kernel.

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

Fix: generate header missing echo -e for escape chars

"why is the -e needed ? What was the experienced oddness ?"

   The \n wasn't getting evaluated to a newline and was being inserted
into the header file as '\n'

   From man echo(1):

       If -e is in effect, the following sequences are recognized:

       \\     backslash

       \a     alert (BEL)

       \b     backspace

       \c     produce no further output

       \e     escape

       \f     form feed

       \n     new line

       \r     carriage return

       \t     horizontal tab

       \v     vertical tab

Suggested-by: Ryan Kyser <Ryan.Kyser@jci.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: add missing uaccess.h include (for ARM)

"What required uaccess.h ?"

   I was getting the following error:
   syscalls_pointers_override.h:6:1: error: implicit declaration of function ?strlen_user?

   I found that strlen_user was defined in asm/uaccess.h, which is
included by linux/uaccess.h.

Suggested-by: Ryan Kyser <Ryan.Kyser@jci.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

README: Document that CONFIG_MODULES is required

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

Fix: README typo

Reported-by: Ryan Kyser <Ryan.Kyser@jci.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: document required and optional kernel config options in README

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

Update version to 2.0.1

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

Fix: is_compat_task !CONFIG_COMPAT compile error on kernels >= 3.3

The Linux kernel already defines a is_compat_task()   (0) when
!CONFIG_COMPAT since kernel 3.3, so if we see it is already defined,
don't redefine it.

Closes #195

Reported-by: David Goulet <dgoulet@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update version to 2.0.0 stable

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

Update version to 2.0.0-rc4

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

Update README and add version name place-holder

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

Update version to 2.0.0-rc3

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

Fix clock offset 32-bit multiplication overflow

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

Fix : wrong assign of fd in state dump

lttng_statedump_file_descriptor was using the tgid instead of the fd for
the fd field.

Reported-by: Mathieu Bain <mathieu.bain@polymtl.ca>
Signed-off-by: Julien Desfossez <julien.desfossez@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

License cleanup, ifdef namespace cleanup

- Spell out the LGPL license completely in each file.
- Change LINUX_* ifdefs for LIB_* in lib/ringbuffer header.

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

Fix: ensure power of 2 check handles 64-bit size_t entirely

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

Update version to 2.0.0-rc2

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

Fix: dmesg printout should not print metadata warnings

Metadata channel retry when an event is dropped by the underlying
buffer. We should not print a message showing that the event has been
dropped to the user on dmesg console.

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

Fix: use transport name as channel name

Clarify dmesg printout.

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

Fix: Return -EINVAL instead of print warning if non power of 2 size/num_subbuf

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

Update Version to 2.0.0-rc1

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

Standardize version across toolchain

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

statedump: Use old macro name for kernel 2.6.38

Signed-off-by: Juha Niskanen <juniskane@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update ChangeLog to 2.0-pre15

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

Add timer instrumentation

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

fix: need to undef mainline define

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

fix: Include signal.h instead of irq.h for prototype match check

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

Add signal instrumentation

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

Update ChangeLog to 2.0-pre14

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

syscall tracing: sys_getcpu

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

Add sys_clone x86 instrumentation

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

statedump: fix include circular dep

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

Implement state dump

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

Update Changelog to 2.0-pre13

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

Update README

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

environment: write sysname, release, version, domain to metadata

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

Allow open /proc/lttng for read & write

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

Update Changelog to 2.0-pre12

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

Add x86 32/64 execve syscall instrumentation override

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

Remove unused defines

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

Add padding to ABI

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

Use LTTNG_KERNEL_SYM_NAME_LEN

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

Update version to 1.9.9

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

Add missing double-quotes to clock uuid

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

clock: read bootid as clock monotonic ID

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

Fix comment

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

Cleanup comment

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

clock: output clock description in metadata

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

Properly fix the timekeeping overflow detection

The underlying issue was a mismatch between the ring buffer
configuration description of the number of clock bits (32) saved and the
actual number used (27).

Introduce LTTNG_COMPACT_EVENT_BITS and LTTNG_COMPACT_TSC_BITS across the
code to remove all hardcoded instances of these values to ensure this
kind of mistake does not happen again.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reported-by: Sébastien Barthélémy <barthelemy@crans.org>

Fix init bug

Fix reversed logic bug introduced by commit
80996790fa42072d6525f2adb9a910312077bef6

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

rename lib-ring-buffer to lttng-lib-ring-buffer

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

Remove #warning

Keep a comment about future work, but don't generate compiler warnings.

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

Mass rename: ltt_*/ltt-* to LTTNG_*/LTTNG-*

For files, defines and symbols.

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

Update TODO

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

Update TODO

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

Remove debugfs file (keep only proc file)

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

Rename lttng-debugfs-abi files to lttng-abi

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

Update ChangeLog for 2.0-pre11

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

Fix OOPS caused by reference of config pointer

The config pointer points to data that may vanish across the life-time
of the ring buffer stream references. It's only kept valid for the
duration between the channel create and destroy, but the streams can
keep an extra reference on the channel, and thus need the config to stay
valid.

Perform a copy of the config rather than keeping a pointer to it.

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

Gather detailed info from x86 64 32-bit compat syscall instrumentation

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

lttng lib: ring buffer move null pointer check to open

Let's move the NULL buf check to the file "open", where it belongs.  The
"open" file operation is the actual interface between lib ring buffer
and the modules using it.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

lttng lib: ring buffer remove duplicate null pointer

This check is performed at mapping setup time in
lib_ring_buffer_mmap_buf() already, so we can safely remove this
duplicata.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

lttng lib: ring buffer: remove stale null-pointer

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

lttng wrapper: add missing include to kallsyms wrapper

Needed to keep bissectability.

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

lttng: cleanup one-bit signed bitfields

* Dan Carpenter <dan.carpenter@oracle.com> wrote:
> Sparse complains that these signed bitfields look "dubious".  The
> problem is that instead of being either 0 or 1 like people would expect,
> signed one bit variables like this are either 0 or -1.  It doesn't cause
> a problem in this case but it's ugly so lets fix them.

* walter harms (wharms@bfs.de) wrote:
> hi,
> This patch looks ok to me but this design is ugly by itself.
> It should be replaced by an uchar uint whatever or use a
> real bool (obviously not preferred by this programmes).

bool :1, uchar :1 or uint :1 could make sense. uchar:1/bool:1 won't save
any space here, because the surrounding fields are either uint or
pointers, so alignment will just add padding.

I try to use int/uint whenever possible because x86 CPUs tend to get
less register false-dependencies when using instructions modifying the
whole register (generated by using int/uint types) rather than only part
of it (uchar/char/bool). I only use char/uchar/bool when there is a
clear wanted space gain.

The reason why I never use the bool type within a structure when I want
a compact representation is that bool takes a whole byte just to
represent one bit:

struct usebitfield {
int a;
unsigned int f:1, g:1, h:1, i:1, j:1;
int b;
};

struct usebool {
int a;
bool f, g, h, i, j;
int b;
};

struct useboolbf {
int a;
bool f:1, g:1, h:1, i:1, j:1;
int b;
};

int main()
{
printf("bitfield %d bytes, bool %d bytes, boolbitfield %d bytes\n",
sizeof(struct usebitfield), sizeof(struct usebool),
sizeof(struct useboolbf));
}

result:

bitfield 12 bytes, bool 16 bytes, boolbitfield 12 bytes

This is because each bool takes one byte, while the bitfields are put in
units of "unsigned int" (or bool for the 3rd struct). So in this
example, we need 5 bytes + 3 bytes alignment for the bool, but only 4
bytes to hold the "unsigned int" unit for the bitfields.

The choice between bool and bitfields must also take into account the
frequency of access to the variable, because bitfields require mask
operations to access the selected bit(s). You will notice that none of
these bitfields are accessed on the tracing fast-path: only in
slow-paths. Therefore, space gain is more important than speed here.

One might argue that I have so few of these fields here that it does not
make an actual difference to go for bitfield or bool. I am just trying
to choose types best suited for their intended purpose, ensuring they
are future-proof and will allow simply adding more fields using the same
type, as needed.

So I guess I'll go for unsigned int :1 (rather than uint:1, so we
keep source-level compatibility with user-space LTTng-UST).

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add TODO file

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

Update symbol name length max size to 256

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

Fix last modifications to string_from_user operations

Signed-off-by: Yannick Brosseau <yannick.brosseau@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Document that depmod needs to be executed by hand

External modules don't seem to actually execute depmod on make install,
even though the console output says so. Document that it needs to be
manually executed in the README file.

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

Fix strlen_user fault space reservation

The previous fix took care of kernel OOPS, but did not reserve space for
the \0.

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

Fix tp_copy_string_from_user handling of faults

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

Disable block layer tracing support for kernels < 2.6.38

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

lttng context: perf counter, fix 32-bit vs 64-bit field size bug

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

Update trace clock warning to match the current development plan

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

ringbuffer: make ring buffer printk less verbose

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

Makefile: do not run depmod manually

The modules_install target of the kernel build infrastructure already
runs depmod properly, taking into account the cross-compilation
case. Therefore, it is useless to re-run depmod here, and also harmful
since it does not work in cross-compilation contexts (it does the
depmod on the modules installed on the host and not the ones being
built for the target).

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>