If there's no tracefs (RHEL7) support the tracing_path_mount returns debugfs path which results in following fail: # perf probe sys_write kprobe_events file does not exist - please rebuild kernel with CONFIG_KPROBE_EVENTS. Error: Failed to add events. In tracing_path_debugfs_mount function we need to return the 'tracing' path instead of just the mount to make it work: # perf probe sys_write Added new event: probe:sys_write (on sys_write) You can now use it in all perf tools, such as: perf record -e probe:sys_write -aR sleep 1 Adding the 'return tracing_path;' also to tracing_path_tracefs_mount function just for consistency with tracing_path_debugfs_mount. Upstream keeps working, because it has the tracefs support. Link: http://lkml.kernel.org/n/tip-yiwkzexq9fk1ey1xg3gnjlw4@git.kernel.org Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Fixes: 23773ca18b39 ("perf tools: Make perf aware of tracefs") Link: http://lkml.kernel.org/r/20181016114818.3595-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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