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2019-05-25tracing: Silence GCC 9 array bounds warningMiguel Ojeda
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 <miguel.ojeda.sandonis@gmail.com> [ Removed unnecessary parenthesis around "iter" ] Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-05-02tracing: kdb: Allow ftdump to skip all but the last few entriesDouglas Anderson
The 'ftdump' command in kdb is currently a bit of a last resort, at least if you have lots of traces turned on. It's going to print a whole boatload of data out your serial port which is probably running at 115200. This could easily take many, many minutes. Usually you're most interested in what's at the _end_ of the ftrace buffer, AKA what happened most recently. That means you've got to wait the full time for the dump. The 'ftdump' command does attempt to help you a little bit by allowing you to skip a fixed number of entries. Unfortunately it provides no way for you to know how many entries you should skip. Let's do similar to python and allow you to use a negative number to indicate that you want to skip all entries except the last few. This allows you to quickly see what you want. Note that we also change the printout in ftdump to print the (positive) number of entries actually skipped since that could be helpful to know when you've specified a negative skip count. Link: http://lkml.kernel.org/r/20190319171206.97107-3-dianders@chromium.org Signed-off-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-05-02tracing: kdb: The skip_lines parameter should have been skip_entriesDouglas Anderson
The things skipped by kdb's "ftdump" command when you pass it a parameter has always been entries, not lines. The difference usually doesn't matter but when the trace buffer has multi-line entries (like a stack dump) it can matter. Let's fix this both in the help text for ftdump and also in the local variable names. Link: http://lkml.kernel.org/r/20190319171206.97107-1-dianders@chromium.org Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-03-13tracing: kdb: Fix ftdump to not sleepDouglas Anderson
As reported back in 2016-11 [1], the "ftdump" kdb command triggers a BUG for "sleeping function called from invalid context". kdb's "ftdump" command wants to call ring_buffer_read_prepare() in atomic context. A very simple solution for this is to add allocation flags to ring_buffer_read_prepare() so kdb can call it without triggering the allocation error. This patch does that. Note that in the original email thread about this, it was suggested that perhaps the solution for kdb was to either preallocate the buffer ahead of time or create our own iterator. I'm hoping that this alternative of adding allocation flags to ring_buffer_read_prepare() can be considered since it means I don't need to duplicate more of the core trace code into "trace_kdb.c" (for either creating my own iterator or re-preparing a ring allocator whose memory was already allocated). NOTE: another option for kdb is to actually figure out how to make it reuse the existing ftrace_dump() function and totally eliminate the duplication. This sounds very appealing and actually works (the "sr z" command can be seen to properly dump the ftrace buffer). The downside here is that ftrace_dump() fully consumes the trace buffer. Unless that is changed I'd rather not use it because it means "ftdump | grep xyz" won't be very useful to search the ftrace buffer since it will throw away the whole trace on the first grep. A future patch to dump only the last few lines of the buffer will also be hard to implement. [1] https://lkml.kernel.org/r/20161117191605.GA21459@google.com Link: http://lkml.kernel.org/r/20190308193205.213659-1-dianders@chromium.org Reported-by: Brian Norris <briannorris@chromium.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-09-30tracing: Move trace_flags from global to a trace_array fieldSteven Rostedt (Red Hat)
In preparation to make trace options per instance, the global trace_flags needs to be moved from being a global variable to a field within the trace instance trace_array structure. There's still more work to do, as there's some functions that use trace_flags without passing in a way to get to the current_trace array. For those, the global_trace is used directly (from trace.c). This includes setting and clearing the trace_flags. This means that when a new instance is created, it just gets the trace_flags of the global_trace and will not be able to modify them. Depending on the functions that have access to the trace_array, the flags of an instance may not affect parts of its trace, where the global_trace is used. These will be fixed in future changes. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-01-09Merge tag 'for_linus-3.19-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb Pull kgdb/kdb fixes from Jason Wessel: "These have been around since 3.17 and in kgdb-next for the last 9 weeks and some will go back to -stable. Summary of changes: Cleanups - kdb: Remove unused command flags, repeat flags and KDB_REPEAT_NONE Fixes - kgdb/kdb: Allow access on a single core, if a CPU round up is deemed impossible, which will allow inspection of the now "trashed" kernel - kdb: Add enable mask for the command groups - kdb: access controls to restrict sensitive commands" * tag 'for_linus-3.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb: kernel/debug/debug_core.c: Logging clean-up kgdb: timeout if secondary CPUs ignore the roundup kdb: Allow access to sensitive commands to be restricted by default kdb: Add enable mask for groups of commands kdb: Categorize kdb commands (similar to SysRq categorization) kdb: Remove KDB_REPEAT_NONE flag kdb: Use KDB_REPEAT_* values as flags kdb: Rename kdb_register_repeat() to kdb_register_flags() kdb: Rename kdb_repeat_t to kdb_cmdflags_t, cmd_repeat to cmd_flags kdb: Remove currently unused kdbtab_t->cmd_flags
2014-11-13tracing: kdb: Fix kernel livelock with empty buffersDaniel Thompson
Currently kdb's ftdump command will livelock by constantly printk'ing the empty string at KERN_EMERG level if it run when the ftrace system is not in use. This occurs because trace_empty() never returns false when the ring buffers are left at the start of a non-consuming read [launched by ring_buffer_read_start()]. This patch changes the loop exit condition to use the result of trace_find_next_entry_inc(). Effectively this switches the non-consuming kdb dumper to follow the approach of the non-consuming userspace interface [s_next()] rather than the consuming ftrace_dump(). Link: http://lkml.kernel.org/r/1415277716-19419-3-git-send-email-daniel.thompson@linaro.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-13tracing: kdb: Fix kernel panic during ftdumpDaniel Thompson
Currently kdb's ftdump command unconditionally crashes due to a null pointer de-reference whenever the command is run. This in turn causes the kernel to panic. The abridged stacktrace (gathered with ARCH=arm) is: --- cut here --- [<c09535ac>] (panic) from [<c02132dc>] (die+0x264/0x440) [<c02132dc>] (die) from [<c0952eb8>] (__do_kernel_fault.part.11+0x74/0x84) [<c0952eb8>] (__do_kernel_fault.part.11) from [<c021f954>] (do_page_fault+0x1d0/0x3c4) [<c021f954>] (do_page_fault) from [<c020846c>] (do_DataAbort+0x48/0xac) [<c020846c>] (do_DataAbort) from [<c0213c58>] (__dabt_svc+0x38/0x60) Exception stack(0xc0deba88 to 0xc0debad0) ba80: e8c29180 00000001 e9854304 e9854300 c0f567d8 c0df2580 baa0: 00000000 00000000 00000000 c0f117b8 c0e3a3c0 c0debb0c 00000000 c0debad0 bac0: 0000672e c02f4d60 60000193 ffffffff [<c0213c58>] (__dabt_svc) from [<c02f4d60>] (kdb_ftdump+0x1e4/0x3d8) [<c02f4d60>] (kdb_ftdump) from [<c02ce328>] (kdb_parse+0x2b8/0x698) [<c02ce328>] (kdb_parse) from [<c02ceef0>] (kdb_main_loop+0x52c/0x784) [<c02ceef0>] (kdb_main_loop) from [<c02d1b0c>] (kdb_stub+0x238/0x490) --- cut here --- The NULL deref occurs due to the initialized use of struct trace_iter's buffer_iter member. This is a regression, albeit a fairly elderly one. It was introduced by commit 6d158a813efc ("tracing: Remove NR_CPUS array from trace_iterator"). This patch solves this by providing a collection of ring_buffer_iter(s) and using this to initialize buffer_iter. Note that static allocation is used solely because the trace_iter itself is also static allocated. Static allocation also means that we have to NULL-ify the pointer during cleanup to avoid use-after-free problems. Link: http://lkml.kernel.org/r/1415277716-19419-2-git-send-email-daniel.thompson@linaro.org Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-11kdb: Categorize kdb commands (similar to SysRq categorization)Daniel Thompson
This patch introduces several new flags to collect kdb commands into groups (later allowing them to be optionally disabled). This follows similar prior art to enable/disable magic sysrq commands. The commands have been categorized as follows: Always on: go (w/o args), env, set, help, ?, cpu (w/o args), sr, dmesg, disable_nmi, defcmd, summary, grephelp Mem read: md, mdr, mdp, mds, ef, bt (with args), per_cpu Mem write: mm Reg read: rd Reg write: go (with args), rm Inspect: bt (w/o args), btp, bta, btc, btt, ps, pid, lsmod Flow ctrl: bp, bl, bph, bc, be, bd, ss Signal: kill Reboot: reboot All: cpu, kgdb, (and all of the above), nmi_console Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2014-11-11kdb: Remove KDB_REPEAT_NONE flagAnton Vorontsov
Since we now treat KDB_REPEAT_* as flags, there is no need to pass KDB_REPEAT_NONE. It's just the default behaviour when no flags are specified. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2014-11-11kdb: Rename kdb_register_repeat() to kdb_register_flags()Anton Vorontsov
We're about to add more options for commands behaviour, so let's give a more generic name to the low-level kdb command registration function. There are just various renames, no functional changes. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-15tracing: Consolidate max_tr into main trace_array structureSteven Rostedt (Red Hat)
Currently, the way the latency tracers and snapshot feature works is to have a separate trace_array called "max_tr" that holds the snapshot buffer. For latency tracers, this snapshot buffer is used to swap the running buffer with this buffer to save the current max latency. The only items needed for the max_tr is really just a copy of the buffer itself, the per_cpu data pointers, the time_start timestamp that states when the max latency was triggered, and the cpu that the max latency was triggered on. All other fields in trace_array are unused by the max_tr, making the max_tr mostly bloat. This change removes the max_tr completely, and adds a new structure called trace_buffer, that holds the buffer pointer, the per_cpu data pointers, the time_start timestamp, and the cpu where the latency occurred. The trace_array, now has two trace_buffers, one for the normal trace and one for the max trace or snapshot. By doing this, not only do we remove the bloat from the max_trace but the instances of traces can now use their own snapshot feature and not have just the top level global_trace have the snapshot feature and latency tracers for itself. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15tracing: Replace the static global per_cpu arrays with allocated per_cpuSteven Rostedt
The global and max-tr currently use static per_cpu arrays for the CPU data descriptors. But in order to get new allocated trace_arrays, they need to be allocated per_cpu arrays. Instead of using the static arrays, switch the global and max-tr to use allocated data. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15tracing: Use RING_BUFFER_ALL_CPUS for TRACE_PIPE_ALL_CPUSteven Rostedt
Both RING_BUFFER_ALL_CPUS and TRACE_PIPE_ALL_CPU are defined as -1 and used to say that all the ring buffers are to be modified or read (instead of just a single cpu, which would be >= 0). There's no reason to keep TRACE_PIPE_ALL_CPU as it is also started to be used for more than what it was created for, and now that the ring buffer code added a generic RING_BUFFER_ALL_CPUS define, we can clean up the trace code to use that instead and remove the TRACE_PIPE_ALL_CPU macro. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-22kdb,ftdump: Remove reference to internal kdb includeJason Wessel
Now that include/linux/kdb.h properly exports all the functions required to dynamically add a kdb shell command, the reference to the private kdb header can be removed. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2010-08-05ftrace,kdb: Allow dumping a specific cpu's buffer with ftdumpJason Wessel
In systems with more than one processor it is desirable to look at the per cpu trace buffers. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> CC: Frederic Weisbecker <fweisbec@gmail.com>
2010-08-05ftrace,kdb: Extend kdb to be able to dump the ftrace bufferJason Wessel
Add in a helper function to allow the kdb shell to dump the ftrace buffer. Modify trace.c to expose the capability to iterate over the ftrace buffer in a read only capacity. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> CC: Frederic Weisbecker <fweisbec@gmail.com>