Commit Graph

10 Commits

Author SHA1 Message Date
Saket Kumar Bhaskar
4b65d5ae97 selftests/bpf: Fix bpf selftest build error
On linux-next, build for bpf selftest displays an error due to
mismatch in the expected function signature of bpf_testmod_test_read
and bpf_testmod_test_write.

Commit 97d06802d1 ("sysfs: constify bin_attribute argument of bin_attribute::read/write()")
changed the required type for struct bin_attribute to const struct bin_attribute.

To resolve the error, update corresponding signature for the callback.

Fixes: 97d06802d1 ("sysfs: constify bin_attribute argument of bin_attribute::read/write()")
Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Closes: https://lore.kernel.org/all/e915da49-2b9a-4c4c-a34f-877f378129f6@linux.ibm.com/
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
Link: https://lore.kernel.org/r/20250512091108.2015615-1-skb99@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-06-01 12:57:41 -07:00
Linus Torvalds
b78f1293f9 tracing updates for v6.16:
- Have module addresses get updated in the persistent ring buffer
 
   The addresses of the modules from the previous boot are saved in the
   persistent ring buffer. If the same modules are loaded and an address is
   in the old buffer points to an address that was both saved in the
   persistent ring buffer and is loaded in memory, shift the address to point
   to the address that is loaded in memory in the trace event.
 
 - Print function names for irqs off and preempt off callsites
 
   When ignoring the print fmt of a trace event and just printing the fields
   directly, have the fields for preempt off and irqs off events still show
   the function name (via kallsyms) instead of just showing the raw address.
 
 - Clean ups of the histogram code
 
   The histogram functions saved over 800 bytes on the stack to process
   events as they come in. Instead, create per-cpu buffers that can hold this
   information and have a separate location for each context level (thread,
   softirq, IRQ and NMI).
 
   Also add some more comments to the code.
 
 - Add "common_comm" field for histograms
 
   Add "common_comm" that uses the current->comm as a field in an event
   histogram and acts like any of the other fields of the event.
 
 - Show "subops" in the enabled_functions file
 
   When the function graph infrastructure is used, a subsystem has a "subops"
   that it attaches its callback function to. Instead of the
   enabled_functions just showing a function calling the function that calls
   the subops functions, also show the subops functions that will get called
   for that function too.
 
 - Add "copy_trace_marker" option to instances
 
   There are cases where an instance is created for tooling to write into,
   but the old tooling has the top level instance hardcoded into the
   application. New tools want to consume the data from an instance and not
   the top level buffer. By adding a copy_trace_marker option, whenever the
   top instance trace_marker is written into, a copy of it is also written
   into the instance with this option set. This allows new tools to read what
   old tools are writing into the top buffer.
 
   If this option is cleared by the top instance, then what is written into
   the trace_marker is not written into the top instance. This is a way to
   redirect the trace_marker writes into another instance.
 
 - Have tracepoints created by DECLARE_TRACE() use trace_<name>_tp()
 
   If a tracepoint is created by DECLARE_TRACE() instead of TRACE_EVENT(),
   then it will not be exposed via tracefs. Currently there's no way to
   differentiate in the kernel the tracepoint functions between those that
   are exposed via tracefs or not. A calling convention has been made
   manually to append a "_tp" prefix for events created by DECLARE_TRACE().
   Instead of doing this manually, force it so that all DECLARE_TRACE()
   events have this notation.
 
 - Use __string() for task->comm in some sched events
 
   Instead of hardcoding the comm to be TASK_COMM_LEN in some of the
   scheduler events use __string() which makes it dynamic. Note, if these
   events are parsed by user space it they may break, and the event may have
   to be converted back to the hardcoded size.
 
 - Have function graph "depth" be unsigned to the user
 
   Internally to the kernel, the "depth" field of the function graph event is
   signed due to -1 being used for end of boundary. What actually gets
   recorded in the event itself is zero or positive. Reflect this to user
   space by showing "depth" as unsigned int and be consistent across all
   events.
 
 - Allow an arbitrary long CPU string to osnoise_cpus_write()
 
   The filtering of which CPUs to write to can exceed 256 bytes. If a machine
   has 256 CPUs, and the filter is to filter every other CPU, the write would
   take a string larger than 256 bytes. Instead of using a fixed size buffer
   on the stack that is 256 bytes, allocate it to handle what is passed in.
 
 - Stop having ftrace check the per-cpu data "disabled" flag
 
   The "disabled" flag in the data structure passed to most ftrace functions
   is checked to know if tracing has been disabled or not. This flag was
   added back in 2008 before the ring buffer had its own way to disable
   tracing. The "disable" flag is now not always set when needed, and the
   ring buffer flag should be used in all locations where the disabled is
   needed. Since the "disable" flag is redundant and incorrect, stop using it.
   Fix up some locations that use the "disable" flag to use the ring buffer
   info.
 
 - Use a new tracer_tracing_disable/enable() instead of data->disable flag
 
   There's a few cases that set the data->disable flag to stop tracing, but
   this flag is not consistently used. It is also an on/off switch where if a
   function set it and calls another function that sets it, the called
   function may incorrectly enable it.
 
   Use a new trace_tracing_disable() and tracer_tracing_enable() that uses a
   counter and can be nested. These use the ring buffer flags which are
   always checked making the disabling more consistent.
 
 - Save the trace clock in the persistent ring buffer
 
   Save what clock was used for tracing in the persistent ring buffer and set
   it back to that clock after a reboot.
 
 - Remove unused reference to a per CPU data pointer in mmiotrace functions
 
 - Remove unused buffer_page field from trace_array_cpu structure
 
 - Remove more strncpy() instances
 
 - Other minor clean ups and fixes
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Merge tag 'trace-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Have module addresses get updated in the persistent ring buffer

   The addresses of the modules from the previous boot are saved in the
   persistent ring buffer. If the same modules are loaded and an address
   is in the old buffer points to an address that was both saved in the
   persistent ring buffer and is loaded in memory, shift the address to
   point to the address that is loaded in memory in the trace event.

 - Print function names for irqs off and preempt off callsites

   When ignoring the print fmt of a trace event and just printing the
   fields directly, have the fields for preempt off and irqs off events
   still show the function name (via kallsyms) instead of just showing
   the raw address.

 - Clean ups of the histogram code

   The histogram functions saved over 800 bytes on the stack to process
   events as they come in. Instead, create per-cpu buffers that can hold
   this information and have a separate location for each context level
   (thread, softirq, IRQ and NMI).

   Also add some more comments to the code.

 - Add "common_comm" field for histograms

   Add "common_comm" that uses the current->comm as a field in an event
   histogram and acts like any of the other fields of the event.

 - Show "subops" in the enabled_functions file

   When the function graph infrastructure is used, a subsystem has a
   "subops" that it attaches its callback function to. Instead of the
   enabled_functions just showing a function calling the function that
   calls the subops functions, also show the subops functions that will
   get called for that function too.

 - Add "copy_trace_marker" option to instances

   There are cases where an instance is created for tooling to write
   into, but the old tooling has the top level instance hardcoded into
   the application. New tools want to consume the data from an instance
   and not the top level buffer. By adding a copy_trace_marker option,
   whenever the top instance trace_marker is written into, a copy of it
   is also written into the instance with this option set. This allows
   new tools to read what old tools are writing into the top buffer.

   If this option is cleared by the top instance, then what is written
   into the trace_marker is not written into the top instance. This is a
   way to redirect the trace_marker writes into another instance.

 - Have tracepoints created by DECLARE_TRACE() use trace_<name>_tp()

   If a tracepoint is created by DECLARE_TRACE() instead of
   TRACE_EVENT(), then it will not be exposed via tracefs. Currently
   there's no way to differentiate in the kernel the tracepoint
   functions between those that are exposed via tracefs or not. A
   calling convention has been made manually to append a "_tp" prefix
   for events created by DECLARE_TRACE(). Instead of doing this
   manually, force it so that all DECLARE_TRACE() events have this
   notation.

 - Use __string() for task->comm in some sched events

   Instead of hardcoding the comm to be TASK_COMM_LEN in some of the
   scheduler events use __string() which makes it dynamic. Note, if
   these events are parsed by user space it they may break, and the
   event may have to be converted back to the hardcoded size.

 - Have function graph "depth" be unsigned to the user

   Internally to the kernel, the "depth" field of the function graph
   event is signed due to -1 being used for end of boundary. What
   actually gets recorded in the event itself is zero or positive.
   Reflect this to user space by showing "depth" as unsigned int and be
   consistent across all events.

 - Allow an arbitrary long CPU string to osnoise_cpus_write()

   The filtering of which CPUs to write to can exceed 256 bytes. If a
   machine has 256 CPUs, and the filter is to filter every other CPU,
   the write would take a string larger than 256 bytes. Instead of using
   a fixed size buffer on the stack that is 256 bytes, allocate it to
   handle what is passed in.

 - Stop having ftrace check the per-cpu data "disabled" flag

   The "disabled" flag in the data structure passed to most ftrace
   functions is checked to know if tracing has been disabled or not.
   This flag was added back in 2008 before the ring buffer had its own
   way to disable tracing. The "disable" flag is now not always set when
   needed, and the ring buffer flag should be used in all locations
   where the disabled is needed. Since the "disable" flag is redundant
   and incorrect, stop using it. Fix up some locations that use the
   "disable" flag to use the ring buffer info.

 - Use a new tracer_tracing_disable/enable() instead of data->disable
   flag

   There's a few cases that set the data->disable flag to stop tracing,
   but this flag is not consistently used. It is also an on/off switch
   where if a function set it and calls another function that sets it,
   the called function may incorrectly enable it.

   Use a new trace_tracing_disable() and tracer_tracing_enable() that
   uses a counter and can be nested. These use the ring buffer flags
   which are always checked making the disabling more consistent.

 - Save the trace clock in the persistent ring buffer

   Save what clock was used for tracing in the persistent ring buffer
   and set it back to that clock after a reboot.

 - Remove unused reference to a per CPU data pointer in mmiotrace
   functions

 - Remove unused buffer_page field from trace_array_cpu structure

 - Remove more strncpy() instances

 - Other minor clean ups and fixes

* tag 'trace-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (36 commits)
  tracing: Fix compilation warning on arm32
  tracing: Record trace_clock and recover when reboot
  tracing/sched: Use __string() instead of fixed lengths for task->comm
  tracepoint: Have tracepoints created with DECLARE_TRACE() have _tp suffix
  tracing: Cleanup upper_empty() in pid_list
  tracing: Allow the top level trace_marker to write into another instances
  tracing: Add a helper function to handle the dereference arg in verifier
  tracing: Remove unnecessary "goto out" that simply returns ret is trigger code
  tracing: Fix error handling in event_trigger_parse()
  tracing: Rename event_trigger_alloc() to trigger_data_alloc()
  tracing: Replace deprecated strncpy() with strscpy() for stack_trace_filter_buf
  tracing: Remove unused buffer_page field from trace_array_cpu structure
  tracing: Use atomic_inc_return() for updating "disabled" counter in irqsoff tracer
  tracing: Convert the per CPU "disabled" counter to local from atomic
  tracing: branch: Use trace_tracing_is_on_cpu() instead of "disabled" field
  ring-buffer: Add ring_buffer_record_is_on_cpu()
  tracing: Do not use per CPU array_buffer.data->disabled for cpumask
  ftrace: Do not disabled function graph based on "disabled" field
  tracing: kdb: Use tracer_tracing_on/off() instead of setting per CPU disabled
  tracing: Use tracer_tracing_disable() instead of "disabled" field for ftrace_dump_one()
  ...
2025-05-29 21:04:36 -07:00
Steven Rostedt
ac01fa73f5 tracepoint: Have tracepoints created with DECLARE_TRACE() have _tp suffix
Most tracepoints in the kernel are created with TRACE_EVENT(). The
TRACE_EVENT() macro (and DECLARE_EVENT_CLASS() and DEFINE_EVENT() where in
reality, TRACE_EVENT() is just a helper macro that calls those other two
macros), will create not only a tracepoint (the function trace_<event>()
used in the kernel), it also exposes the tracepoint to user space along
with defining what fields will be saved by that tracepoint.

There are a few places that tracepoints are created in the kernel that are
not exposed to userspace via tracefs. They can only be accessed from code
within the kernel. These tracepoints are created with DEFINE_TRACE()

Most of these tracepoints end with "_tp". This is useful as when the
developer sees that, they know that the tracepoint is for in-kernel only
(meaning it can only be accessed inside the kernel, either directly by the
kernel or indirectly via modules and BPF programs) and is not exposed to
user space.

Instead of making this only a process to add "_tp", enforce it by making
the DECLARE_TRACE() append the "_tp" suffix to the tracepoint. This
requires adding DECLARE_TRACE_EVENT() macros for the TRACE_EVENT() macro
to use that keeps the original name.

Link: https://lore.kernel.org/all/20250418083351.20a60e64@gandalf.local.home/

Cc: netdev <netdev@vger.kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Ahern <dsahern@kernel.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/20250510163730.092fad5b@gandalf.local.home
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-05-14 11:19:32 -04:00
Feng Yang
9b72f3e5b7 selftests/bpf: Add test for attaching kprobe with long event names
This test verifies that attaching kprobe/kretprobe with long event names
does not trigger EINVAL errors.

Signed-off-by: Feng Yang <yangfeng@kylinos.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250417014848.59321-4-yangfeng59949@163.com
2025-04-22 17:13:37 -07:00
Chen Ni
c966139485 selftests/bpf: Convert comma to semicolon
Replace comma between expressions with semicolons.

Using a ',' in place of a ';' can have unintended side effects.
Although that is not the case here, it is seems best to use ';'
unless ',' is intended.

Found by inspection.
No functional change intended.
Compile tested only.

Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Link: https://lore.kernel.org/bpf/20250401061546.1990156-1-nichen@iscas.ac.cn
2025-04-04 08:53:57 -07:00
Amery Hung
4e4136c644 selftests/bpf: Test gen_pro/epilogue that generate kfuncs
Test gen_prologue and gen_epilogue that generate kfuncs that have not
been seen in the main program.

The main bpf program and return value checks are identical to
pro_epilogue.c introduced in commit 47e69431b5 ("selftests/bpf: Test
gen_prologue and gen_epilogue"). However, now when bpf_testmod_st_ops
detects a program name with prefix "test_kfunc_", it generates slightly
different prologue and epilogue: They still add 1000 to args->a in
prologue, add 10000 to args->a and set r0 to 2 * args->a in epilogue,
but involve kfuncs.

At high level, the alternative version of prologue and epilogue look
like this:

  cgrp = bpf_cgroup_from_id(0);
  if (cgrp)
          bpf_cgroup_release(cgrp);
  else
          /* Perform what original bpf_testmod_st_ops prologue or
           * epilogue does
           */

Since 0 is never a valid cgroup id, the original prologue or epilogue
logic will be performed. As a result, the __retval check should expect
the exact same return value.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20250225233545.285481-2-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-02-25 19:04:43 -08:00
Amery Hung
63817c7711 selftests/bpf: Test struct_ops program with __ref arg calling bpf_tail_call
Test if the verifier rejects struct_ops program with __ref argument
calling bpf_tail_call().

Signed-off-by: Amery Hung <ameryhung@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250220221532.1079331-2-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-02-20 18:44:35 -08:00
Amery Hung
af17bad9fb selftests/bpf: Test returning referenced kptr from struct_ops programs
Test struct_ops programs returning referenced kptr. When the return type
of a struct_ops operator is pointer to struct, the verifier should
only allow programs that return a scalar NULL or a non-local kptr with the
correct type in its unmodified form.

Signed-off-by: Amery Hung <amery.hung@bytedance.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20250217190640.1748177-6-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-02-17 18:47:27 -08:00
Amery Hung
6991ec6beb selftests/bpf: Test referenced kptr arguments of struct_ops programs
Test referenced kptr acquired through struct_ops argument tagged with
"__ref". The success case checks whether 1) a reference to the correct
type is acquired, and 2) the referenced kptr argument can be accessed in
multiple paths as long as it hasn't been released. In the fail cases,
we first confirm that a referenced kptr acquried through a struct_ops
argument is not allowed to be leaked. Then, we make sure this new
referenced kptr acquiring mechanism does not accidentally allow referenced
kptrs to flow into global subprograms through their arguments.

Signed-off-by: Amery Hung <amery.hung@bytedance.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20250217190640.1748177-4-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-02-17 18:47:27 -08:00
Toke Høiland-Jørgensen
d6212d82bf selftests/bpf: Consolidate kernel modules into common directory
The selftests build four kernel modules which use copy-pasted Makefile
targets. This is a bit messy, and doesn't scale so well when we add more
modules, so let's consolidate these rules into a single rule generated
for each module name, and move the module sources into a single
directory.

To avoid parallel builds of the different modules stepping on each
other's toes during the 'modpost' phase of the Kbuild 'make modules',
the module files should really be a grouped target. However, make only
added explicit support for grouped targets in version 4.3, which is
newer than the minimum version supported by the kernel. However, make
implicitly treats pattern matching rules with multiple targets as a
grouped target, so we can work around this by turning the rule into a
pattern matching target. We do this by replacing '.ko' with '%ko' in the
targets with subst().

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Viktor Malik <vmalik@redhat.com>
Link: https://lore.kernel.org/bpf/20241204-bpf-selftests-mod-compile-v5-1-b96231134a49@redhat.com
2024-12-06 10:44:10 -08:00