hamza.kesraoui/sst-linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

scripts/sorttable: fix orc_sort_cmp() to maintain symmetry and transitivity

Browse Source 
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: 57fa189942 ("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>
This commit is contained in:
Kuan-Wei Chiu 2025-01-07 01:44:59 +08:00 committed by Greg Kroah-Hartman
parent d23f2621fc
commit 939d239fe8
1 changed files with 5 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
scripts/sorttable.h
View File

@ -110,7 +110,7 @@ static inline unsigned long orc_ip(const int *ip)
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 +128,10 @@ static int orc_sort_cmp(const void *_a, const void *_b)
* 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->sp_reg == ORC_REG_UNDEFINED && !orc_a->end &&
orc_b->sp_reg == ORC_REG_UNDEFINED && !orc_b->end)
return 0;
return orc_a->sp_reg == ORC_REG_UNDEFINED && !orc_a->end ? -1 : 1;
}