linux-stable.git/kernel/trace/trace_kprobe.c, branch v3.2.99

tracing/kprobes: Allow to create probe with a module name starting with a digit

2017-09-15T17:30:56+00:00

commit 9e52b32567126fe146f198971364f68d3bc5233f upstream.

Always try to parse an address, since kstrtoul() will safely fail when
given a symbol as input. If that fails (which will be the case for a
symbol), try to parse a symbol instead.

This allows creating a probe such as:

    p:probe/vlan_gro_receive 8021q:vlan_gro_receive+0

Which is necessary for this command to work:

    perf probe -m 8021q -a vlan_gro_receive

Link: http://lkml.kernel.org/r/fd72d666f45b114e2c5b9cf7e27b91de1ec966f1.1498122881.git.sd@queasysnail.net

Fixes: 413d37d1e ("tracing: Add kprobe-based event tracer")
Acked-by: Masami Hiramatsu 
Signed-off-by: Sabrina Dubroca 
Signed-off-by: Steven Rostedt (VMware) 
[bwh: Backported to 3.2: preserve the check that an addresses isn't used for
 a kretprobe]
Signed-off-by: Ben Hutchings

tracing/kprobes: Enforce kprobes teardown after testing

2017-09-15T17:30:44+00:00

commit 30e7d894c1478c88d50ce94ddcdbd7f9763d9cdd upstream.

Enabling the tracer selftest triggers occasionally the warning in
text_poke(), which warns when the to be modified page is not marked
reserved.

The reason is that the tracer selftest installs kprobes on functions marked
__init for testing. These probes are removed after the tests, but that
removal schedules the delayed kprobes_optimizer work, which will do the
actual text poke. If the work is executed after the init text is freed,
then the warning triggers. The bug can be reproduced reliably when the work
delay is increased.

Flush the optimizer work and wait for the optimizing/unoptimizing lists to
become empty before returning from the kprobes tracer selftest. That
ensures that all operations which were queued due to the probes removal
have completed.

Link: http://lkml.kernel.org/r/20170516094802.76a468bb@gandalf.local.home

Signed-off-by: Thomas Gleixner 
Acked-by: Masami Hiramatsu 
Fixes: 6274de498 ("kprobes: Support delayed unoptimizing")
Signed-off-by: Steven Rostedt (VMware) 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

ftrace/kprobes: Fix not to delete probes if in use

2011-10-10T19:13:03+00:00

Fix kprobe-tracer not to delete a probe if the probe is in use.
In that case, delete operation will return -EBUSY.

This bug can cause a kernel panic if enabled probes are deleted
during perf record.

(Add some probes on functions)
sh-4.2# perf probe --del probe:\*
sh-4.2# exit
(kernel panic)

This is originally reported on the fedora bugzilla:

 https://bugzilla.redhat.com/show_bug.cgi?id=742383

I've also checked that this problem doesn't happen on
tracepoints when module removing because perf event
locks target module.

$ sudo ./perf record -e xfs:\* -aR sh
sh-4.2# rmmod xfs
ERROR: Module xfs is in use
sh-4.2# exit
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.203 MB perf.data (~8862 samples) ]

Signed-off-by: Masami Hiramatsu 
Cc: Arnaldo Carvalho de Melo 
Cc: Ingo Molnar 
Cc: Frederic Weisbecker 
Cc: Frank Ch. Eigler 
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/20111004104438.14591.6553.stgit@fedora15
Signed-off-by: Steven Rostedt

tracing/kprobe: Update symbol reference when loading module

2011-07-15T19:45:32+00:00

Since the address of a module-local variable can only be
solved after the target module is loaded, the symbol
fetch-argument should be updated when loading target
module.

Signed-off-by: Masami Hiramatsu 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Frederic Weisbecker 
Cc: Arnaldo Carvalho de Melo 
Link: http://lkml.kernel.org/r/20110627072703.6528.75042.stgit@fedora15
Signed-off-by: Steven Rostedt

tracing/kprobes: Support module init function probing

2011-07-15T19:17:14+00:00

To support probing module init functions, kprobe-tracer allows
user to define a probe on non-existed function when it is given
with a module name. This also enables user to set a probe on
a function on a specific module, even if a same name (but different)
function is locally defined in another module.

The module name must be in the front of function name and separated
by a ':'. e.g. btrfs:btrfs_init_sysfs

Signed-off-by: Masami Hiramatsu 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Frederic Weisbecker 
Cc: Arnaldo Carvalho de Melo 
Link: http://lkml.kernel.org/r/20110627072656.6528.89970.stgit@fedora15
Signed-off-by: Steven Rostedt

tracing/kprobes: Merge trace probe enable/disable functions

2011-07-15T19:10:58+00:00

Merge redundant enable/disable functions into enable_trace_probe()
and disable_trace_probe().

Signed-off-by: Masami Hiramatsu 
Cc: Arnaldo Carvalho de Melo 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Link: http://lkml.kernel.org/r/20110627072644.6528.26910.stgit@fedora15

[ converted kprobe selftest to use  enable_trace_probe ]

Signed-off-by: Steven Rostedt

tracing/kprobes: Rename probe_* to trace_probe_*

2011-07-14T21:44:43+00:00

Rename probe_* to trace_probe_* for avoiding namespace
confliction. This also fixes improper names of find_probe_event()
and cleanup_all_probes() to find_trace_probe() and
release_all_trace_probes() respectively.

Signed-off-by: Masami Hiramatsu 
Cc: Arnaldo Carvalho de Melo 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Frederic Weisbecker 
Link: http://lkml.kernel.org/r/20110627072636.6528.60374.stgit@fedora15
Signed-off-by: Steven Rostedt

Merge branch 'tip/perf/core-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core

2011-07-05T09:55:43+00:00

tracing/kprobes: Fix kprobe-tracer to support stack trace

2011-06-15T02:48:53+00:00

Fix to support kernel stack trace correctly on kprobe-tracer.
Since the execution path of kprobe-based dynamic events is different
from other tracepoint-based events, normal ftrace_trace_stack() doesn't
work correctly. To fix that, this introduces ftrace_trace_stack_regs()
which traces stack via pt_regs instead of current stack register.

e.g.

 # echo p schedule+4 > /sys/kernel/debug/tracing/kprobe_events
 # echo 1 > /sys/kernel/debug/tracing/options/stacktrace
 # echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable
 # head -n 20 /sys/kernel/debug/tracing/trace
            bash-2968  [000] 10297.050245: p_schedule_4: (schedule+0x4/0x4ca)
            bash-2968  [000] 10297.050247: 
 => schedule_timeout
 => n_tty_read
 => tty_read
 => vfs_read
 => sys_read
 => system_call_fastpath
     kworker/0:1-2940  [000] 10297.050265: p_schedule_4: (schedule+0x4/0x4ca)
     kworker/0:1-2940  [000] 10297.050266: 
 => worker_thread
 => kthread
 => kernel_thread_helper
            sshd-1132  [000] 10297.050365: p_schedule_4: (schedule+0x4/0x4ca)
            sshd-1132  [000] 10297.050365: 
 => sysret_careful

Note: Even with this fix, the first entry will be skipped
if the probe is put on the function entry area before
the frame pointer is set up (usually, that is 4 bytes
 (push %bp; mov %sp %bp) on x86), because stack unwinder
depends on the frame pointer.

Signed-off-by: Masami Hiramatsu 
Cc: Frederic Weisbecker 
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Peter Zijlstra 
Cc: Namhyung Kim 
Link: http://lkml.kernel.org/r/20110608070934.17777.17116.stgit@fedora15
Signed-off-by: Steven Rostedt

kprobes/trace: Fix kprobe selftest for gcc 4.6

2011-06-07T18:47:36+00:00

With gcc 4.6, the self test kprobe function:

 kprobe_trace_selftest_target()

is optimized such that kallsyms does not list it. The kprobes
test uses this function to insert a probe and test it. But
it will fail the test if the function is not listed in kallsyms.

Adding a __used annotation keeps the symbol in the kallsyms table.

Suggested-by: David Daney 
Cc: Masami Hiramatsu 
Signed-off-by: Steven Rostedt