linux.git/scripts/sorttable.h, branch v6.6.132 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git scripts/sorttable: fix orc_sort_cmp() to maintain symmetry and transitivity 2025-01-09T12:32:07+00:00 Kuan-Wei Chiu visitorckw@gmail.com 2024-12-26T14:03:32+00:00 c9818b61d0a859ecec77ec3253b418dc89e5e695 commit 0210d251162f4033350a94a43f95b1c39ec84a90 upstream. 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_TYPE_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_TYPE_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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 0210d251162f4033350a94a43f95b1c39ec84a90 upstream.

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_TYPE_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_TYPE_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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86,objtool: Split UNWIND_HINT_EMPTY in two 2023-03-23T22:18:58+00:00 Josh Poimboeuf jpoimboe@kernel.org 2023-03-01T15:13:12+00:00 fb799447ae2974a07907906dff5bd4b9e47b7123 Mark reported that the ORC unwinder incorrectly marks an unwind as reliable when the unwind terminates prematurely in the dark corners of return_to_handler() due to lack of information about the next frame. The problem is UNWIND_HINT_EMPTY is used in two different situations: 1) The end of the kernel stack unwind before hitting user entry, boot code, or fork entry 2) A blind spot in ORC coverage where the unwinder has to bail due to lack of information about the next frame The ORC unwinder has no way to tell the difference between the two. When it encounters an undefined stack state with 'end=1', it blindly marks the stack reliable, which can break the livepatch consistency model. Fix it by splitting UNWIND_HINT_EMPTY into UNWIND_HINT_UNDEFINED and UNWIND_HINT_END_OF_STACK. Reported-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/fd6212c8b450d3564b855e1cb48404d6277b4d9f.1677683419.git.jpoimboe@kernel.org 
Mark reported that the ORC unwinder incorrectly marks an unwind as
reliable when the unwind terminates prematurely in the dark corners of
return_to_handler() due to lack of information about the next frame.

The problem is UNWIND_HINT_EMPTY is used in two different situations:

  1) The end of the kernel stack unwind before hitting user entry, boot
     code, or fork entry

  2) A blind spot in ORC coverage where the unwinder has to bail due to
     lack of information about the next frame

The ORC unwinder has no way to tell the difference between the two.
When it encounters an undefined stack state with 'end=1', it blindly
marks the stack reliable, which can break the livepatch consistency
model.

Fix it by splitting UNWIND_HINT_EMPTY into UNWIND_HINT_UNDEFINED and
UNWIND_HINT_END_OF_STACK.

Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/fd6212c8b450d3564b855e1cb48404d6277b4d9f.1677683419.git.jpoimboe@kernel.org
script/sorttable: Fix some initialization problems 2022-01-18T15:17:18+00:00 Yinan Liu yinan@linux.alibaba.com 2022-01-18T06:52:41+00:00 35140d399db2b67153fc53b51a97ddb8ba3b5956 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> 
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>
scripts: ftrace - move the sort-processing in ftrace_init 2022-01-13T21:23:04+00:00 Yinan Liu yinan@linux.alibaba.com 2021-12-12T11:33:58+00:00 72b3942a173c387b27860ba1069636726e208777 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> 
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>
script/sorttable: Code style improvements 2021-12-11T14:34:31+00:00 Yinan Liu yinan@linux.alibaba.com 2021-12-07T15:13:47+00:00 c8a7ff13f5fc6e6b313de2a8e02304c2a90a3906 Modified the code style issue of if() {}, keep the code style consistent. Link: https://lkml.kernel.org/r/20211207151348.54921-3-yinan@linux.alibaba.com Signed-off-by: Yinan Liu <yinan@linux.alibaba.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> 
Modified the code style issue of if() {},
keep the code style consistent.

Link: https://lkml.kernel.org/r/20211207151348.54921-3-yinan@linux.alibaba.com

Signed-off-by: Yinan Liu <yinan@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
scripts/sorttable: Implement build-time ORC unwind table sorting 2019-12-13T09:47:58+00:00 Shile Zhang shile.zhang@linux.alibaba.com 2019-12-04T00:46:32+00:00 57fa1899428538e314a7e0d52a5b617af082389a 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> 
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>
scripts/sorttable: Rename 'sortextable' to 'sorttable' 2019-12-13T09:47:58+00:00 Shile Zhang shile.zhang@linux.alibaba.com 2019-12-04T00:46:31+00:00 1091670637be8bd34a39dd1ddcc0a10a7c88d4e2 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> 
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>