kernel/linux.git/Documentation/trace, branch v6.12.80

Documentation: tracing: Add PCI tracepoint documentation

2026-03-04T12:19:59+00:00

[ Upstream commit 8236fc613d44e59f6736d6c3e9efffaf26ab7f00 ] The PCI tracing system provides tracepoints to monitor critical hardware events that can impact system performance and reliability. Add documentation about it. Signed-off-by: Shuai Xue [bhelgaas: squash fixes: https://lore.kernel.org/r/20260108013956.14351-2-bagasdotme@gmail.com https://lore.kernel.org/r/20260108013956.14351-3-bagasdotme@gmail.com] Signed-off-by: Bjorn Helgaas Reviewed-by: Ilpo Järvinen Link: https://patch.msgid.link/20251210132907.58799-4-xueshuai@linux.alibaba.com Signed-off-by: Sasha Levin

Documentation: trace: Refactor toctree

2026-03-04T12:19:59+00:00

[ Upstream commit f0ba72e65516d1d86f40c79a49c4ba01c9555592 ] Refactor table of contents of kernel tracing subsystem docs to improve clarity, structure, and organization: - Reformat sections and add appropriate headings - Improve section grouping and refine descriptions for each group - Add docs intro paragraph Signed-off-by: Purva Yeshi Link: https://lore.kernel.org/r/20250318113230.24950-2-purvayeshi550@gmail.com [Bagas: massage commit message and address reviews] Co-developed-by: Bagas Sanjaya Signed-off-by: Bagas Sanjaya Acked-by: Steven Rostedt (Google) Signed-off-by: Jonathan Corbet Stable-dep-of: 8236fc613d44 ("Documentation: tracing: Add PCI tracepoint documentation") Signed-off-by: Sasha Levin

docs: fix WARNING document not included in any toctree

2026-03-04T12:19:59+00:00

[ Upstream commit 998bece1d22bf2cbc819cb3a492148932d4e12a8 ] Add debugging.rst to the relevant toctree to fix warning about missing documentation inclusion in toctree. Signed-off-by: SurajSonawane2415 Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20241002195817.22972-1-surajsonawane0215@gmail.com Stable-dep-of: 8236fc613d44 ("Documentation: tracing: Add PCI tracepoint documentation") Signed-off-by: Sasha Levin

Documentation: trace: historgram-design: Separate sched_waking histogram section heading and the following diagram

2025-10-15T10:00:13+00:00

[ Upstream commit 8c716e87ea33519920811338100d6d8a7fb32456 ] Section heading for sched_waking histogram is shown as normal paragraph instead due to codeblock marker for the following diagram being in the same line as the section underline. Separate them. Fixes: daceabf1b494 ("tracing/doc: Fix ascii-art in histogram-design.rst") Reviewed-by: Tom Zanussi Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Bagas Sanjaya Acked-by: Steven Rostedt (Google) Signed-off-by: Jonathan Corbet Message-ID: <20250916054202.582074-5-bagasdotme@gmail.com> Signed-off-by: Sasha Levin

tracing/Documentation: Start a document on how to debug with tracing

2024-08-26T17:54:08+00:00

Add a new document Documentation/trace/debugging.rst that will hold various ways to debug tracing. This initial version mentions trace_printk and how to create persistent buffers that can last across bootups. Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Andrew Morton Cc: Vincent Donnefort Cc: Joel Fernandes Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vineeth Pillai Cc: Beau Belgrave Cc: Alexander Graf Cc: Baoquan He Cc: Borislav Petkov Cc: "Paul E. McKenney" Cc: David Howells Cc: Mike Rapoport Cc: Dave Hansen Cc: Tony Luck Cc: Guenter Roeck Cc: Ross Zwisler Cc: Kees Cook Cc: Alexander Aring Cc: "Luis Claudio R. Goncalves" Cc: Tomas Glozar Cc: John Kacur Cc: Clark Williams Cc: Linus Torvalds Cc: "Jonathan Corbet" Link: https://lore.kernel.org/20240823014019.702433486@goodmis.org Signed-off-by: Steven Rostedt (Google)

tracing: Add option to set an instance to be the trace_printk destination

2024-08-26T17:54:08+00:00

Add a option "trace_printk_dest" that will make the tracing instance the location that trace_printk() will go to. This is useful if the trace_printk or one of the top level tracers is too noisy and there's a need to separate the two. Then an instance can be created, the trace_printk can be set to go there instead, where it will not be lost in the noise of the top level tracer. Note, only one instance can be the destination of trace_printk at a time. If an instance sets this flag, the instance that had it set will have it cleared. There is always one instance that has this set. By default, that is the top instance. This flag cannot be cleared from the top instance. Doing so will result in an -EINVAL. The only way this flag can be cleared from the top instance is by another instance setting it. Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Andrew Morton Cc: Vincent Donnefort Cc: Joel Fernandes Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vineeth Pillai Cc: Beau Belgrave Cc: Alexander Graf Cc: Baoquan He Cc: Borislav Petkov Cc: "Paul E. McKenney" Cc: David Howells Cc: Mike Rapoport Cc: Dave Hansen Cc: Tony Luck Cc: Guenter Roeck Cc: Ross Zwisler Cc: Kees Cook Cc: Alexander Aring Cc: "Luis Claudio R. Goncalves" Cc: Tomas Glozar Cc: John Kacur Cc: Clark Williams Cc: Linus Torvalds Cc: "Jonathan Corbet" Link: https://lore.kernel.org/20240823014019.545459018@goodmis.org Signed-off-by: Steven Rostedt (Google)

Merge tag 'ftrace-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2024-07-18T20:36:33+00:00

Pull ftrace updates from Steven Rostedt: "Rewrite of function graph tracer to allow multiple users Up until now, the function graph tracer could only have a single user attached to it. If another user tried to attach to the function graph tracer while one was already attached, it would fail. Allowing function graph tracer to have more than one user has been asked for since 2009, but it required a rewrite to the logic to pull it off so it never happened. Until now! There's three systems that trace the return of a function. That is kretprobes, function graph tracer, and BPF. kretprobes and function graph tracing both do it similarly. The difference is that kretprobes uses a shadow stack per callback and function graph tracer creates a shadow stack for all tasks. The function graph tracer method makes it possible to trace the return of all functions. As kretprobes now needs that feature too, allowing it to use function graph tracer was needed. BPF also wants to trace the return of many probes and its method doesn't scale either. Having it use function graph tracer would improve that. By allowing function graph tracer to have multiple users allows both kretprobes and BPF to use function graph tracer in these cases. This will allow kretprobes code to be removed in the future as it's version will no longer be needed. Note, function graph tracer is only limited to 16 simultaneous users, due to shadow stack size and allocated slots" * tag 'ftrace-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (49 commits) fgraph: Use str_plural() in test_graph_storage_single() function_graph: Add READ_ONCE() when accessing fgraph_array[] ftrace: Add missing kerneldoc parameters to unregister_ftrace_direct() function_graph: Everyone uses HAVE_FUNCTION_GRAPH_RET_ADDR_PTR, remove it function_graph: Fix up ftrace_graph_ret_addr() function_graph: Make fgraph_update_pid_func() a stub for !DYNAMIC_FTRACE function_graph: Rename BYTE_NUMBER to CHAR_NUMBER in selftests fgraph: Remove some unused functions ftrace: Hide one more entry in stack trace when ftrace_pid is enabled function_graph: Do not update pid func if CONFIG_DYNAMIC_FTRACE not enabled function_graph: Make fgraph_do_direct static key static ftrace: Fix prototypes for ftrace_startup/shutdown_subops() ftrace: Assign RCU list variable with rcu_assign_ptr() ftrace: Assign ftrace_list_end to ftrace_ops_list type cast to RCU ftrace: Declare function_trace_op in header to quiet sparse warning ftrace: Add comments to ftrace_hash_move() and friends ftrace: Convert "inc" parameter to bool in ftrace_hash_rec_update_modify() ftrace: Add comments to ftrace_hash_rec_disable/enable() ftrace: Remove "filter_hash" parameter from __ftrace_hash_rec_update() ftrace: Rename dup_hash() and comment it ...

rtla/osnoise: set the default threshold to 1us

2024-07-01T22:54:31+00:00

Change the default threshold for osnoise to 1us, so that any noise equal or above this value is recorded. Let the user set a higher threshold if necessary. Link: https://lore.kernel.org/linux-trace-kernel/Zmb-QhiiiI6jM9To@uudg.org Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Jonathan Corbet Suggested-by: Daniel Bristot de Oliveira Reviewed-by: Clark Williams Signed-off-by: Luis Claudio R. Goncalves Acked-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google)

function_graph: Everyone uses HAVE_FUNCTION_GRAPH_RET_ADDR_PTR, remove it

2024-06-11T15:18:24+00:00

All architectures that implement function graph also implements HAVE_FUNCTION_GRAPH_RET_ADDR_PTR. Remove it, as it is no longer a differentiator. Link: https://lore.kernel.org/linux-trace-kernel/20240611031737.982047614@goodmis.org Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Jonathan Corbet Cc: Catalin Marinas Cc: Will Deacon Cc: Guo Ren Cc: Huacai Chen Cc: WANG Xuerui Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Christophe Leroy Cc: "Naveen N. Rao" Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: Sven Schnelle Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: "H. Peter Anvin" Signed-off-by: Steven Rostedt (Google)

Merge tag 'char-misc-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2024-05-22T19:26:46+00:00

Pull char/misc and other driver subsystem updates from Greg KH: "Here is the big set of char/misc and other driver subsystem updates for 6.10-rc1. Nothing major here, just lots of new drivers and updates for apis and new hardware types. Included in here are: - big IIO driver updates with more devices and drivers added - fpga driver updates - hyper-v driver updates - uio_pruss driver removal, no one uses it, other drivers control the same hardware now - binder minor updates - mhi driver updates - excon driver updates - counter driver updates - accessability driver updates - coresight driver updates - other hwtracing driver updates - nvmem driver updates - slimbus driver updates - spmi driver updates - other smaller misc and char driver updates All of these have been in linux-next for a while with no reported issues" * tag 'char-misc-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (319 commits) misc: ntsync: mark driver as "broken" to prevent from building spmi: pmic-arb: Add multi bus support spmi: pmic-arb: Register controller for bus instead of arbiter spmi: pmic-arb: Make core resources acquiring a version operation spmi: pmic-arb: Make the APID init a version operation spmi: pmic-arb: Fix some compile warnings about members not being described dt-bindings: spmi: Deprecate qcom,bus-id dt-bindings: spmi: Add X1E80100 SPMI PMIC ARB schema spmi: pmic-arb: Replace three IS_ERR() calls by null pointer checks in spmi_pmic_arb_probe() spmi: hisi-spmi-controller: Do not override device identifier dt-bindings: spmi: hisilicon,hisi-spmi-controller: clean up example dt-bindings: spmi: hisilicon,hisi-spmi-controller: fix binding references spmi: make spmi_bus_type const extcon: adc-jack: Document missing struct members extcon: realtek: Remove unused of_gpio.h extcon: usbc-cros-ec: Convert to platform remove callback returning void extcon: usb-gpio: Convert to platform remove callback returning void extcon: max77843: Convert to platform remove callback returning void extcon: max3355: Convert to platform remove callback returning void extcon: intel-mrfld: Convert to platform remove callback returning void ...