The orc_sort_cmp() function, used with qsort(), previously violated the
symmetry and transitivity rules required by the C standard. Specifically,
when both entries are ORC_REG_UNDEFINED, it could result in both a < b
and b < a, which breaks the required symmetry and transitivity. This can
lead to undefined behavior and incorrect sorting results, potentially
causing memory corruption in glibc implementations [1].
Symmetry: If x < y, then y > x.
Transitivity: If x < y and y < z, then x < z.
Fix the comparison logic to return 0 when both entries are
ORC_REG_UNDEFINED, ensuring compliance with qsort() requirements.
Link: https://www.qualys.com/2024/01/30/qsort.txt [1]
Link: https://lkml.kernel.org/r/20241226140332.2670689-1-visitorckw@gmail.com
Fixes: 57fa18994285 ("scripts/sorttable: Implement build-time ORC unwind table sorting")
Fixes: fb799447ae29 ("x86,objtool: Split UNWIND_HINT_EMPTY in two")
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: <chuang@cs.nycu.edu.tw>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shile Zhang <shile.zhang@linux.alibaba.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit 0210d251162f4033350a94a43f95b1c39ec84a90)
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
elf_mcount_loc and mcount_sort_thread definitions are not
initialized immediately within the function, which can cause
the judgment logic to use uninitialized values when the
initialization logic of subsequent code fails.
Link: https://lkml.kernel.org/r/20211212113358.34208-2-yinan@linux.alibaba.com
Link: https://lkml.kernel.org/r/20220118065241.42364-1-yinan@linux.alibaba.com
Fixes: 72b3942a173c ("scripts: ftrace - move the sort-processing in ftrace_init")
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Yinan Liu <yinan@linux.alibaba.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When the kernel starts, the initialization of ftrace takes
up a portion of the time (approximately 6~8ms) to sort mcount
addresses. We can save this time by moving mcount-sorting to
compile time.
Link: https://lkml.kernel.org/r/20211212113358.34208-2-yinan@linux.alibaba.com
Signed-off-by: Yinan Liu <yinan@linux.alibaba.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The ORC unwinder has two tables: .orc_unwind_ip and .orc_unwind, which
need to be sorted for binary search. Previously this sorting was done
during bootup.
Sort them at build time to speed up booting.
Add the ORC tables sorting in a parallel build process to speed up the build.
[ mingo: Rewrote the changelog and fixed some comments. ]
Suggested-by: Andy Lutomirski <luto@amacapital.net>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: linux-kbuild@vger.kernel.org
Link: https://lkml.kernel.org/r/20191204004633.88660-7-shile.zhang@linux.alibaba.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Use a more generic name for additional table sorting usecases,
such as the upcoming ORC table sorting feature. This tool is
not tied to exception table sorting anymore.
No functional changes intended.
[ mingo: Rewrote the changelog. ]
Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: linux-kbuild@vger.kernel.org
Link: https://lkml.kernel.org/r/20191204004633.88660-6-shile.zhang@linux.alibaba.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
