linux/kernel/trace/trace.h, branch v5.4

tracing: Add tracing_check_open_get_tr()

2019-10-13T00:44:07Z

Currently, most files in the tracefs directory test if tracing_disabled is set. If so, it should return -ENODEV. The tracing_disabled is called when tracing is found to be broken. Originally it was done in case the ring buffer was found to be corrupted, and we wanted to prevent reading it from crashing the kernel. But it's also called if a tracing selftest fails on boot. It's a one way switch. That is, once it is triggered, tracing is disabled until reboot. As most tracefs files can also be used by instances in the tracefs directory, they need to be carefully done. Each instance has a trace_array associated to it, and when the instance is removed, the trace_array is freed. But if an instance is opened with a reference to the trace_array, then it requires looking up the trace_array to get its ref counter (as there could be a race with it being deleted and the open itself). Once it is found, a reference is added to prevent the instance from being removed (and the trace_array associated with it freed). Combine the two checks (tracing_disabled and trace_array_get()) into a single helper function. This will also make it easier to add lockdown to tracefs later. Link: http://lkml.kernel.org/r/20191011135458.7399da44@gandalf.local.home Signed-off-by: Steven Rostedt (VMware)

tracing: Have trace events system open call tracing_open_generic_tr()

2019-10-13T00:43:00Z

Instead of having the trace events system open call open code the taking of the trace_array descriptor (with trace_array_get()) and then calling trace_open_generic(), have it use the tracing_open_generic_tr() that does the combination of the two. This requires making tracing_open_generic_tr() global. Signed-off-by: Steven Rostedt (VMware)

tracing: Fix clang -Wint-in-bool-context warnings in IF_ASSIGN macro

2019-09-28T21:13:39Z

After r372664 in clang, the IF_ASSIGN macro causes a couple hundred warnings along the lines of: kernel/trace/trace_output.c:1331:2: warning: converting the enum constant to a boolean [-Wint-in-bool-context] kernel/trace/trace.h:409:3: note: expanded from macro 'trace_assign_type' IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry, ^ kernel/trace/trace.h:371:14: note: expanded from macro 'IF_ASSIGN' WARN_ON(id && (entry)->type != id); \ ^ 264 warnings generated. This warning can catch issues with constructs like: if (state == A || B) where the developer really meant: if (state == A || state == B) This is currently the only occurrence of the warning in the kernel tree across defconfig, allyesconfig, allmodconfig for arm32, arm64, and x86_64. Add the implicit '!= 0' to the WARN_ON statement to fix the warnings and find potential issues in the future. Link: https://github.com/llvm/llvm-project/commit/28b38c277a2941e9e891b2db30652cfd962f070b Link: https://github.com/ClangBuiltLinux/linux/issues/686 Link: http://lkml.kernel.org/r/20190926162258.466321-1-natechancellor@gmail.com Reviewed-by: Nick Desaulniers Signed-off-by: Nathan Chancellor Signed-off-by: Steven Rostedt (VMware)

tracing: Rename tracing_reset() to tracing_reset_cpu()

2019-08-31T16:19:40Z

The name tracing_reset() was a misnomer, as it really only reset a single CPU buffer. Rename it to tracing_reset_cpu() and also make it static and remove the prototype from trace.h, as it is only used in a single function. Signed-off-by: Steven Rostedt (VMware)

tracing: Silence GCC 9 array bounds warning

2019-05-26T03:04:30Z

Starting with GCC 9, -Warray-bounds detects cases when memset is called starting on a member of a struct but the size to be cleared ends up writing over further members. Such a call happens in the trace code to clear, at once, all members after and including `seq` on struct trace_iterator: In function 'memset', inlined from 'ftrace_dump' at kernel/trace/trace.c:8914:3: ./include/linux/string.h:344:9: warning: '__builtin_memset' offset [8505, 8560] from the object at 'iter' is out of the bounds of referenced subobject 'seq' with type 'struct trace_seq' at offset 4368 [-Warray-bounds] 344 | return __builtin_memset(p, c, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ In order to avoid GCC complaining about it, we compute the address ourselves by adding the offsetof distance instead of referring directly to the member. Since there are two places doing this clear (trace.c and trace_kdb.c), take the chance to move the workaround into a single place in the internal header. Link: http://lkml.kernel.org/r/20190523124535.GA12931@gmail.com Signed-off-by: Miguel Ojeda [ Removed unnecessary parenthesis around "iter" ] Signed-off-by: Steven Rostedt (VMware)

kernel/trace/trace.h: Remove duplicate header of trace_seq.h

2019-05-22T19:37:41Z

Remove duplicate header which is included twice. Link: http://lkml.kernel.org/r/1553725186-41442-1-git-send-email-jagdsh.linux@gmail.com Reviewed-by: Mukesh Ojha Signed-off-by: Jagadeesh Pagadala Signed-off-by: Steven Rostedt (VMware)

Merge tag 'trace-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2019-05-15T23:05:47Z

Pull tracing updates from Steven Rostedt: "The major changes in this tracing update includes: - Removal of non-DYNAMIC_FTRACE from 32bit x86 - Removal of mcount support from x86 - Emulating a call from int3 on x86_64, fixes live kernel patching - Consolidated Tracing Error logs file Minor updates: - Removal of klp_check_compiler_support() - kdb ftrace dumping output changes - Accessing and creating ftrace instances from inside the kernel - Clean up of #define if macro - Introduction of TRACE_EVENT_NOP() to disable trace events based on config options And other minor fixes and clean ups" * tag 'trace-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits) x86: Hide the int3_emulate_call/jmp functions from UML livepatch: Remove klp_check_compiler_support() ftrace/x86: Remove mcount support ftrace/x86_32: Remove support for non DYNAMIC_FTRACE tracing: Simplify "if" macro code tracing: Fix documentation about disabling options using trace_options tracing: Replace kzalloc with kcalloc tracing: Fix partial reading of trace event's id file tracing: Allow RCU to run between postponed startup tests tracing: Fix white space issues in parse_pred() function tracing: Eliminate const char[] auto variables ring-buffer: Fix mispelling of Calculate tracing: probeevent: Fix to make the type of $comm string tracing: probeevent: Do not accumulate on ret variable tracing: uprobes: Re-enable $comm support for uprobe events ftrace/x86_64: Emulate call function while updating in breakpoint handler x86_64: Allow breakpoints to emulate call instructions x86_64: Add gap to int3 to allow for call emulation tracing: kdb: Allow ftdump to skip all but the last few entries tracing: Add trace_total_entries() / trace_total_entries_cpu() ...

tracing: Add trace_total_entries() / trace_total_entries_cpu()

2019-05-03T01:32:31Z

These two new exported functions will be used in a future patch by kdb_ftdump() to quickly skip all but the last few trace entries. Link: http://lkml.kernel.org/r/20190319171206.97107-2-dianders@chromium.org Acked-by: Daniel Thompson Suggested-by: Steven Rostedt Signed-off-by: Douglas Anderson Signed-off-by: Steven Rostedt (VMware)

tracing: Make ftrace_trace_userstack() static and conditional

2019-04-29T10:37:55Z

It's only used in trace.c and there is absolutely no point in compiling it in when user space stack traces are not supported. Signed-off-by: Thomas Gleixner Reviewed-by: Steven Rostedt Reviewed-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Alexander Potapenko Cc: Alexey Dobriyan Cc: Andrew Morton Cc: Christoph Lameter Cc: Pekka Enberg Cc: linux-mm@kvack.org Cc: David Rientjes Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport Cc: Akinobu Mita Cc: Christoph Hellwig Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy Cc: Marek Szyprowski Cc: Johannes Thumshirn Cc: David Sterba Cc: Chris Mason Cc: Josef Bacik Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer Cc: Alasdair Kergon Cc: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen Cc: Maarten Lankhorst Cc: dri-devel@lists.freedesktop.org Cc: David Airlie Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Tom Zanussi Cc: Miroslav Benes Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094803.162400595@linutronix.de

tracing: Have the error logs show up in the proper instances

2019-04-08T13:22:44Z

As each instance has their own error_log file, it makes more sense that the instances show the errors of their own instead of all error_logs having the same data. Make it that the errors show up in the instance error_log file that the error happens in. If no instance trace_array is available, then NULL can be passed in which will create the error in the top level instance (the one at the top of the tracefs directory). Reviewed-by: Masami Hiramatsu Reviewed-by: Tom Zanussi Tested-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware)