The patch titled Subject: scripts/sorttable: fix orc_sort_cmp() to maintain symmetry and transitivity has been added to the -mm mm-hotfixes-unstable branch. Its filename is scripts-sorttable-fix-orc_sort_cmp-to-maintain-symmetry-and-transitivity.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------ From: Kuan-Wei Chiu visitorckw@gmail.com Subject: scripts/sorttable: fix orc_sort_cmp() to maintain symmetry and transitivity Date: Thu, 26 Dec 2024 22:03:32 +0800
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 ---
scripts/sorttable.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/scripts/sorttable.h~scripts-sorttable-fix-orc_sort_cmp-to-maintain-symmetry-and-transitivity +++ a/scripts/sorttable.h @@ -110,7 +110,7 @@ static inline unsigned long orc_ip(const
static int orc_sort_cmp(const void *_a, const void *_b) { - struct orc_entry *orc_a; + struct orc_entry *orc_a, *orc_b; const int *a = g_orc_ip_table + *(int *)_a; const int *b = g_orc_ip_table + *(int *)_b; unsigned long a_val = orc_ip(a); @@ -128,6 +128,9 @@ static int orc_sort_cmp(const void *_a, * whitelisted .o files which didn't get objtool generation. */ orc_a = g_orc_table + (a - g_orc_ip_table); + orc_b = g_orc_table + (b - g_orc_ip_table); + if (orc_a->type == ORC_TYPE_UNDEFINED && orc_b->type == ORC_TYPE_UNDEFINED) + return 0; return orc_a->type == ORC_TYPE_UNDEFINED ? -1 : 1; }
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Patches currently in -mm which might be from visitorckw@gmail.com are
scripts-sorttable-fix-orc_sort_cmp-to-maintain-symmetry-and-transitivity.patch lib-min_heap-improve-type-safety-in-min_heap-macros-by-using-container_of.patch lib-test_min_heap-use-inline-min-heap-variants-to-reduce-attack-vector.patch lib-min_heap-add-brief-introduction-to-min-heap-api.patch documentation-core-api-min_heap-add-author-information.patch