e16c2ce7c5
Commit da231338ec9c0987 ("perf record: Use an eventfd to wakeup when
done") uses eventfd() to solve a rare race where the setting and
checking of 'done' which add done_fd to pollfd. When draining buffer,
revents of done_fd is 0 and evlist__filter_pollfd function returns a
non-zero value. As a result, perf record does not stop profiling.
The following simple scenarios can trigger this condition:
# sleep 10 &
# perf record -p $!
After the sleep process exits, perf record should stop profiling and exit.
However, perf record keeps running.
If pollfd revents contains only POLLERR or POLLHUP, perf record
indicates that buffer is draining and need to stop profiling. Use
fdarray_flag__nonfilterable() to set done eventfd to nonfilterable
objects, so that evlist__filter_pollfd() does not filter and check done
eventfd.
Fixes: da231338ec9c0987 ("perf record: Use an eventfd to wakeup when done")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: zhangjinhao2@huawei.com
Link: http://lore.kernel.org/lkml/20210205065001.23252-1-yangjihong1@huawei.com
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.
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.