During early boot, while KASAN is not yet initialized, it is possible to enter reporting code-path and end up in kasan_report(). While uninitialized, the branch there prevents generating any reports, however, under certain circumstances when branches are being traced (TRACE_BRANCH_PROFILING), we may recurse deep enough to cause kernel reboots without warning. To prevent similar issues in future, we should disable branch tracing for the core runtime. [elver@google.com: remove duplicate DISABLE_BRANCH_PROFILING, per Qian Cai] Link: https://lore.kernel.org/lkml/20200517011732.GE24705@shao2-debian/ Link: http://lkml.kernel.org/r/20200522075207.157349-1-elver@google.com Reported-by: kernel test robot <rong.a.chen@intel.com> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Qian Cai <cai@lca.pw> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r//20200517011732.GE24705@shao2-debian/ Link: http://lkml.kernel.org/r/20200519182459.87166-1-elver@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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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