linux.git/kernel/trace, branch v4.17

tracing: Make the snapshot trigger work with instances

2018-05-28T16:49:32+00:00

The snapshot trigger currently only affects the main ring buffer, even when
it is used by the instances. This can be confusing as the snapshot trigger
is listed in the instance.

 > # cd /sys/kernel/tracing
 > # mkdir instances/foo
 > # echo snapshot > instances/foo/events/syscalls/sys_enter_fchownat/trigger
 > # echo top buffer > trace_marker
 > # echo foo buffer > instances/foo/trace_marker
 > # touch /tmp/bar
 > # chown rostedt /tmp/bar
 > # cat instances/foo/snapshot
 # tracer: nop
 #
 #
 # * Snapshot is freed *
 #
 # Snapshot commands:
 # echo 0 > snapshot : Clears and frees snapshot buffer
 # echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.
 #                      Takes a snapshot of the main buffer.
 # echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)
 #                      (Doesn't have to be '2' works with any number that
 #                       is not a '0' or '1')

 > # cat snapshot
 # tracer: nop
 #
 #                              _-----=> irqs-off
 #                             / _----=> need-resched
 #                            | / _---=> hardirq/softirq
 #                            || / _--=> preempt-depth
 #                            ||| /     delay
 #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
 #              | |       |   ||||       |         |
             bash-1189  [000] ....   111.488323: tracing_mark_write: top buffer

Not only did the snapshot occur in the top level buffer, but the instance
snapshot buffer should have been allocated, and it is still free.

Cc: stable@vger.kernel.org
Fixes: 85f2b08268c01 ("tracing: Add basic event trigger framework")
Signed-off-by: Steven Rostedt (VMware)

tracing: Fix crash when freeing instances with event triggers

2018-05-28T00:54:44+00:00

If a instance has an event trigger enabled when it is freed, it could cause
an access of free memory. Here's the case that crashes:

 # cd /sys/kernel/tracing
 # mkdir instances/foo
 # echo snapshot > instances/foo/events/initcall/initcall_start/trigger
 # rmdir instances/foo

Would produce:

 general protection fault: 0000 [#1] PREEMPT SMP PTI
 Modules linked in: tun bridge ...
 CPU: 5 PID: 6203 Comm: rmdir Tainted: G        W         4.17.0-rc4-test+ #933
 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016
 RIP: 0010:clear_event_triggers+0x3b/0x70
 RSP: 0018:ffffc90003783de0 EFLAGS: 00010286
 RAX: 0000000000000000 RBX: 6b6b6b6b6b6b6b2b RCX: 0000000000000000
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8800c7130ba0
 RBP: ffffc90003783e00 R08: ffff8801131993f8 R09: 0000000100230016
 R10: ffffc90003783d80 R11: 0000000000000000 R12: ffff8800c7130ba0
 R13: ffff8800c7130bd8 R14: ffff8800cc093768 R15: 00000000ffffff9c
 FS:  00007f6f4aa86700(0000) GS:ffff88011eb40000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007f6f4a5aed60 CR3: 00000000cd552001 CR4: 00000000001606e0
 Call Trace:
  event_trace_del_tracer+0x2a/0xc5
  instance_rmdir+0x15c/0x200
  tracefs_syscall_rmdir+0x52/0x90
  vfs_rmdir+0xdb/0x160
  do_rmdir+0x16d/0x1c0
  __x64_sys_rmdir+0x17/0x20
  do_syscall_64+0x55/0x1a0
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

This was due to the call the clears out the triggers when an instance is
being deleted not removing the trigger from the link list.

Cc: stable@vger.kernel.org
Fixes: 85f2b08268c01 ("tracing: Add basic event trigger framework")
Signed-off-by: Steven Rostedt (VMware)

tracing: Fix regex_match_front() to not over compare the test string

2018-05-11T14:56:42+00:00

The regex match function regex_match_front() in the tracing filter logic,
was fixed to test just the pattern length from testing the entire test
string. That is, it went from strncmp(str, r->pattern, len) to
strcmp(str, r->pattern, r->len).

The issue is that str is not guaranteed to be nul terminated, and if r->len
is greater than the length of str, it can access more memory than is
allocated.

The solution is to add a simple test if (len < r->len) return 0.

Cc: stable@vger.kernel.org
Fixes: 285caad415f45 ("tracing/filters: Fix MATCH_FRONT_ONLY filter matching")
Signed-off-by: Steven Rostedt (VMware)

Merge tag 'trace-v4.17-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2018-05-05T06:57:28+00:00

Pull tracing fixes from Steven Rostedt:
 "Some of the files in the tracing directory show file mode 0444 when
  they are writable by root. To fix the confusion, they should be 0644.
  Note, either case root can still write to them.

  Zhengyuan asked why I never applied that patch (the first one is from
  2014!). I simply forgot about it. /me lowers head in shame"

* tag 'trace-v4.17-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix the file mode of stack tracer
  ftrace: Have set_graph_* files have normal file modes

tracing: Fix the file mode of stack tracer

2018-05-03T15:58:05+00:00

It looks weird that the stack_trace_filter file can be written by root
but shows that it does not have write permission by ll command.

Link: http://lkml.kernel.org/r/1518054113-28096-1-git-send-email-liuzhengyuan@kylinos.cn

Signed-off-by: Zhengyuan Liu 
Signed-off-by: Steven Rostedt (VMware)

ftrace: Have set_graph_* files have normal file modes

2018-05-03T15:55:31+00:00

The set_graph_function and set_graph_notrace file mode should be 0644
instead of 0444 as they are writeable. Note, the mode appears to be ignored
regardless, but they should at least look sane.

Link: http://lkml.kernel.org/r/1409725869-4501-1-git-send-email-linx.z.chen@intel.com

Acked-by: Namhyung Kim 
Signed-off-by: Chen LinX 
Signed-off-by: Steven Rostedt (VMware)

Merge tag 'trace-v4.17-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2018-05-03T03:38:37+00:00

Pull tracing fixes from Steven Rostedt:
 "Various fixes in tracing:

   - Tracepoints should not give warning on OOM failures

   - Use special field for function pointer in trace event

   - Fix igrab issues in uprobes

   - Fixes to the new histogram triggers"

* tag 'trace-v4.17-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracepoint: Do not warn on ENOMEM
  tracing: Add field modifier parsing hist error for hist triggers
  tracing: Add field parsing hist error for hist triggers
  tracing: Restore proper field flag printing when displaying triggers
  tracing: initcall: Ordered comparison of function pointers
  tracing: Remove igrab() iput() call from uprobes.c
  tracing: Fix bad use of igrab in trace_uprobe.c

Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-04-29T16:03:25+00:00

Pull timer fixes from Thomas Gleixner:
 "Two fixes from the timer departement:

   - Fix a long standing issue in the NOHZ tick code which causes RB
     tree corruption, delayed timers and other malfunctions. The cause
     for this is code which modifies the expiry time of an enqueued
     hrtimer.

   - Revert the CLOCK_MONOTONIC/CLOCK_BOOTTIME unification due to
     regression reports. Seems userspace _is_ relying on the documented
     behaviour despite our hope that it wont"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIME
  tick/sched: Do not mess with an enqueued hrtimer

tracing: Add field modifier parsing hist error for hist triggers

2018-04-27T01:39:58+00:00

If the user specifies an invalid field modifier for a hist trigger,
the current code correctly flags that as an error, but doesn't tell
the user what happened.

Fix this by invoking hist_err() with an appropriate message when
invalid modifiers are specified.

Before:

  # echo 'hist:keys=pid:ts0=common_timestamp.junkusecs' >> /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
  -su: echo: write error: Invalid argument
  # cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/hist

After:

  # echo 'hist:keys=pid:ts0=common_timestamp.junkusecs' >> /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
  -su: echo: write error: Invalid argument
  # cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/hist
  ERROR: Invalid field modifier: junkusecs
    Last command: keys=pid:ts0=common_timestamp.junkusecs

Link: http://lkml.kernel.org/r/b043c59fa79acd06a5f14a1d44dee9e5a3cd1248.1524790601.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi 
Signed-off-by: Steven Rostedt (VMware)

tracing: Add field parsing hist error for hist triggers

2018-04-27T01:39:32+00:00

If the user specifies a nonexistent field for a hist trigger, the
current code correctly flags that as an error, but doesn't tell the
user what happened.

Fix this by invoking hist_err() with an appropriate message when
nonexistent fields are specified.

Before:

  # echo 'hist:keys=pid:ts0=common_timestamp.usecs' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
  -su: echo: write error: Invalid argument
  # cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist

After:

  # echo 'hist:keys=pid:ts0=common_timestamp.usecs' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
  -su: echo: write error: Invalid argument
  # cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist
  ERROR: Couldn't find field: pid
    Last command: keys=pid:ts0=common_timestamp.usecs

Link: http://lkml.kernel.org/r/fdc8746969d16906120f162b99dd71c741e0b62c.1524790601.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi 
Reported-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)