6347244316
Since __sanitizer_cov_trace_const_cmp4 is marked as notrace, the function called from __sanitizer_cov_trace_const_cmp4 shouldn't be traceable either. ftrace_graph_caller() gets called every time func write_comp_data() gets called if it isn't marked 'notrace'. This is the backtrace from gdb: #0 ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179 #1 0xffffff8010201920 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:151 #2 0xffffff8010439714 in write_comp_data (type=5, arg1=0, arg2=0, ip=18446743524224276596) at ../kernel/kcov.c:116 #3 0xffffff8010439894 in __sanitizer_cov_trace_const_cmp4 (arg1=<optimized out>, arg2=<optimized out>) at ../kernel/kcov.c:188 #4 0xffffff8010201874 in prepare_ftrace_return (self_addr=18446743524226602768, parent=0xffffff801014b918, frame_pointer=18446743524223531344) at ./include/generated/atomic-instrumented.h:27 #5 0xffffff801020194c in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:182 Rework so that write_comp_data() that are called from __sanitizer_cov_trace_*_cmp*() are marked as 'notrace'. Commit 903e8ff86753 ("kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc() as notrace") missed to mark write_comp_data() as 'notrace'. When that patch was created gcc-7 was used. In lib/Kconfig.debug config KCOV_ENABLE_COMPARISONS depends on $(cc-option,-fsanitize-coverage=trace-cmp) That code path isn't hit with gcc-7. However, it were that with gcc-8. Link: http://lkml.kernel.org/r/20181206143011.23719-1-anders.roxell@linaro.org Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Co-developed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> 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.