Fix a use after put reference count issue. maps is copied from leader, but the leader is put on line 79 and then maps is used to read the reference count below - so a use after put, with the put of maps happening within thread__put. Fix by reversing the order of puts so that the leader is put last. To explain the reference count checker, I wrote this up as a little example here: https://perf.wiki.kernel.org/index.php/Reference_Count_Checking Note, the bug was introduced by the committer and wasn't present in the original reference count patch set. Committer notes: Yes, the bug predated your patch and is detected by the reference count checking you contributed. This was just part of splitting up your series into smaller chunks, in this case either we fix the problem detected while developing this reference counting infrastructure before the patch introducing REFCNT_CHECKING or fix it later after the merged infrastructure, when built with EXTRA_CFLAGS="-DREFCNT_CHECKING=1" detects it when running 'perf test', which is what this patch does. Signed-off-by: Ian Rogers <irogers@google.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lore.kernel.org/lkml/20230420030430.489243-1-irogers@google.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.
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