linux-toradex.git/kernel/trace/trace_selftest.c, branch v6.12-rc1

tracing: Fix memory leak in fgraph storage selftest

2024-08-21T19:10:33+00:00

With ftrace boot-time selftest, kmemleak reported some memory leaks in
the new test case for function graph storage for multiple tracers.

unreferenced object 0xffff888005060080 (size 32):
  comm "swapper/0", pid 1, jiffies 4294676440
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 20 10 06 05 80 88 ff ff  ........ .......
    54 0c 1e 81 ff ff ff ff 00 00 00 00 00 00 00 00  T...............
  backtrace (crc 7c93416c):
    [<000000000238ee6f>] __kmalloc_cache_noprof+0x11f/0x2a0
    [<0000000033d2b6c5>] enter_record+0xe8/0x150
    [<0000000054c38424>] match_records+0x1cd/0x230
    [<00000000c775b63d>] ftrace_set_hash+0xff/0x380
    [<000000007bf7208c>] ftrace_set_filter+0x70/0x90
    [<00000000a5c08dda>] test_graph_storage_multi+0x2e/0xf0
    [<000000006ba028ca>] trace_selftest_startup_function_graph+0x1e8/0x260
    [<00000000a715d3eb>] run_tracer_selftest+0x111/0x190
    [<00000000395cbf90>] register_tracer+0xdf/0x1f0
    [<0000000093e67f7b>] do_one_initcall+0x141/0x3b0
    [<00000000c591b682>] do_initcall_level+0x82/0xa0
    [<000000004e4c6600>] do_initcalls+0x43/0x70
    [<0000000034f3c4e4>] kernel_init_freeable+0x170/0x1f0
    [<00000000c7a5dab2>] kernel_init+0x1a/0x1a0
    [<00000000ea105947>] ret_from_fork+0x3a/0x50
    [<00000000a1932e84>] ret_from_fork_asm+0x1a/0x30
...

This means filter hash allocated for the fixtures are not correctly
released after the test.

Free those hash lists after tests are done and split the loop for
initialize fixture and register fixture for rollback.

Fixes: dd120af2d5f8 ("ftrace: Add multiple fgraph storage selftest")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/172411539857.28895.13119957560263401102.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt (Google)

fgraph: Use str_plural() in test_graph_storage_single()

2024-07-01T23:57:51+00:00

Use existing str_plural() function rather than duplicating its
implementation.

./kernel/trace/trace_selftest.c:880:56-60: opportunity for str_plural(size).

Link: https://lore.kernel.org/linux-trace-kernel/20240618072014.20855-1-jiapeng.chong@linux.alibaba.com

Reported-by: Abaci Robot 
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9349
Signed-off-by: Jiapeng Chong 
Acked-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt (Google)

function_graph: Rename BYTE_NUMBER to CHAR_NUMBER in selftests

2024-06-06T19:22:19+00:00

The function_graph selftests checks various size variables to pass from
the entry of the function to the exit. It tests 1, 2, 4 and 8 byte words.
The 1 byte macro was called BYTE_NUMBER but that is used in the sh
architecture: arch/sh/include/asm/bitops-op32.h

Just rename the macro to CHAR_NUMBER.

Link: https://lore.kernel.org/linux-trace-kernel/20240606081846.4cb82dc4@gandalf.local.home

Cc: Masami Hiramatsu 
Cc: Mark Rutland 
Cc: Mathieu Desnoyers 
Fixes: 47c3c70aa3697 ("function_graph: Add selftest for passing local variables")
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202406061744.rZDXfRrG-lkp@intel.com/
Signed-off-by: Steven Rostedt (Google)

ftrace: Add multiple fgraph storage selftest

2024-06-04T14:37:59+00:00

Add a selftest for multiple function graph tracer with storage on a same
function. In this case, the shadow stack entry will be shared among those
fgraph with different data storage. So this will ensure the fgraph will
not mixed those storage data.

Link: https://lore.kernel.org/linux-trace-kernel/171509111465.162236.3795819216426570800.stgit@devnote2
Link: https://lore.kernel.org/linux-trace-kernel/20240603190824.284049716@goodmis.org

Cc: Mark Rutland 
Cc: Mathieu Desnoyers 
Cc: Andrew Morton 
Cc: Alexei Starovoitov 
Cc: Florent Revest 
Cc: Martin KaFai Lau 
Cc: bpf 
Cc: Sven Schnelle 
Cc: Alexei Starovoitov 
Cc: Jiri Olsa 
Cc: Arnaldo Carvalho de Melo 
Cc: Daniel Borkmann 
Cc: Alan Maguire 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Guo Ren 
Reviewed-by: Masami Hiramatsu (Google) 
Signed-off-by: Masami Hiramatsu (Google) 
Suggested-by: Steven Rostedt (Google) 
Signed-off-by: Steven Rostedt (Google)

function_graph: Add selftest for passing local variables

2024-06-04T14:37:52+00:00

Add boot up selftest that passes variables from a function entry to a
function exit, and make sure that they do get passed around.

Co-developed with Masami Hiramatsu:
Link: https://lore.kernel.org/linux-trace-kernel/171509110271.162236.11047551496319744627.stgit@devnote2
Link: https://lore.kernel.org/linux-trace-kernel/20240603190824.122952310@goodmis.org

Cc: Mark Rutland 
Cc: Mathieu Desnoyers 
Cc: Andrew Morton 
Cc: Alexei Starovoitov 
Cc: Florent Revest 
Cc: Martin KaFai Lau 
Cc: bpf 
Cc: Sven Schnelle 
Cc: Alexei Starovoitov 
Cc: Jiri Olsa 
Cc: Arnaldo Carvalho de Melo 
Cc: Daniel Borkmann 
Cc: Alan Maguire 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Guo Ren 
Reviewed-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt (Google)

ftrace: Allow function_graph tracer to be enabled in instances

2024-06-04T14:36:28+00:00

Now that function graph tracing can handle more than one user, allow it to
be enabled in the ftrace instances. Note, the filtering of the functions is
still joined by the top level set_ftrace_filter and friends, as well as the
graph and nograph files.

Co-developed with Masami Hiramatsu:
Link: https://lore.kernel.org/linux-trace-kernel/171509099743.162236.1699959255446248163.stgit@devnote2
Link: https://lore.kernel.org/linux-trace-kernel/20240603190822.190630762@goodmis.org

Cc: Mark Rutland 
Cc: Mathieu Desnoyers 
Cc: Andrew Morton 
Cc: Alexei Starovoitov 
Cc: Florent Revest 
Cc: Martin KaFai Lau 
Cc: bpf 
Cc: Sven Schnelle 
Cc: Alexei Starovoitov 
Cc: Jiri Olsa 
Cc: Arnaldo Carvalho de Melo 
Cc: Daniel Borkmann 
Cc: Alan Maguire 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Guo Ren 
Reviewed-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt (Google)

ftrace/function_graph: Pass fgraph_ops to function graph callbacks

2024-06-04T14:36:22+00:00

Pass the fgraph_ops structure to the function graph callbacks. This will
allow callbacks to add a descriptor to a fgraph_ops private field that wil
be added in the future and use it for the callbacks. This will be useful
when more than one callback can be registered to the function graph tracer.

Co-developed with Masami Hiramatsu:
Link: https://lore.kernel.org/linux-trace-kernel/171509098588.162236.4787930115997357578.stgit@devnote2
Link: https://lore.kernel.org/linux-trace-kernel/20240603190822.035147698@goodmis.org

Cc: Mark Rutland 
Cc: Mathieu Desnoyers 
Cc: Andrew Morton 
Cc: Alexei Starovoitov 
Cc: Florent Revest 
Cc: Martin KaFai Lau 
Cc: bpf 
Cc: Sven Schnelle 
Cc: Alexei Starovoitov 
Cc: Jiri Olsa 
Cc: Arnaldo Carvalho de Melo 
Cc: Daniel Borkmann 
Cc: Alan Maguire 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Guo Ren 
Reviewed-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt (Google)

tracing: Support to dump instance traces by ftrace_dump_on_oops

2024-03-18T14:33:06+00:00

Currently ftrace only dumps the global trace buffer on an OOPs. For
debugging a production usecase, instance trace will be helpful to
check specific problems since global trace buffer may be used for
other purposes.

This patch extend the ftrace_dump_on_oops parameter to dump a specific
or multiple trace instances:

  - ftrace_dump_on_oops=0: as before -- don't dump
  - ftrace_dump_on_oops[=1]: as before -- dump the global trace buffer
  on all CPUs
  - ftrace_dump_on_oops=2 or =orig_cpu: as before -- dump the global
  trace buffer on CPU that triggered the oops
  - ftrace_dump_on_oops=: new behavior -- dump the
  tracing instance matching 
  - ftrace_dump_on_oops[=2/orig_cpu],[=2/orig_cpu],
  [=2/orig_cpu]: new behavior -- dump the global trace
  buffer and multiple instance buffer on all CPUs, or only dump on CPU
  that triggered the oops if =2 or =orig_cpu is given

Also, the sysctl node can handle the input accordingly.

Link: https://lore.kernel.org/linux-trace-kernel/20240223083126.1817731-1-quic_hyiwei@quicinc.com

Cc: Ross Zwisler 
Cc: 
Cc: 
Cc: 
Cc: 
Cc: 
Cc: 
Cc: 
Signed-off-by: Huang Yiwei 
Signed-off-by: Steven Rostedt (Google)

tracing: Have function_graph selftest call cond_resched()

2023-05-29T01:15:46+00:00

When all kernel debugging is enabled (lockdep, KSAN, etc), the function
graph enabling and disabling can take several seconds to complete. The
function_graph selftest enables and disables function graph tracing
several times. With full debugging enabled, the soft lockup watchdog was
triggering because the selftest was running without ever scheduling.

Add cond_resched() throughout the test to make sure it does not trigger
the soft lockup detector.

Link: https://lkml.kernel.org/r/20230528051742.1325503-6-rostedt@goodmis.org

Signed-off-by: Steven Rostedt (Google)

ftrace: selftest: remove broken trace_direct_tramp

2023-03-21T17:59:29+00:00

The ftrace selftest code has a trace_direct_tramp() function which it
uses as a direct call trampoline. This happens to work on x86, since the
direct call's return address is in the usual place, and can be returned
to via a RET, but in general the calling convention for direct calls is
different from regular function calls, and requires a trampoline written
in assembly.

On s390, regular function calls place the return address in %r14, and an
ftrace patch-site in an instrumented function places the trampoline's
return address (which is within the instrumented function) in %r0,
preserving the original %r14 value in-place. As a regular C function
will return to the address in %r14, using a C function as the trampoline
results in the trampoline returning to the caller of the instrumented
function, skipping the body of the instrumented function.

Note that the s390 issue is not detcted by the ftrace selftest code, as
the instrumented function is trivial, and returning back into the caller
happens to be equivalent.

On arm64, regular function calls place the return address in x30, and
an ftrace patch-site in an instrumented function saves this into r9
and places the trampoline's return address (within the instrumented
function) in x30. A regular C function will return to the address in
x30, but will not restore x9 into x30. Consequently, using a C function
as the trampoline results in returning to the trampoline's return
address having corrupted x30, such that when the instrumented function
returns, it will return back into itself.

To avoid future issues in this area, remove the trace_direct_tramp()
function, and require that each architecture with direct calls provides
a stub trampoline, named ftrace_stub_direct_tramp. This can be written
to handle the architecture's trampoline calling convention, and in
future could be used elsewhere (e.g. in the ftrace ops sample, to
measure the overhead of direct calls), so we may as well always build it
in.

Link: https://lkml.kernel.org/r/20230321140424.345218-8-revest@chromium.org

Signed-off-by: Mark Rutland 
Cc: Li Huafei 
Cc: Xu Kuohai 
Signed-off-by: Florent Revest 
Acked-by: Jiri Olsa 
Signed-off-by: Steven Rostedt (Google)