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| author | Kuan-Wei Chiu <visitorckw@gmail.com> | 2024-12-26 15:03:32 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-12-31 02:59:11 +0100 |
| commit | 0210d251162f4033350a94a43f95b1c39ec84a90 (patch) | |
| tree | 4fbb01aa7345b32b027fab1af097fe6a26dcac99 /scripts | |
| parent | mm/util: make memdup_user_nul() similar to memdup_user() (diff) | |
| download | linux-0210d251162f4033350a94a43f95b1c39ec84a90.tar.xz linux-0210d251162f4033350a94a43f95b1c39ec84a90.zip | |
scripts/sorttable: fix orc_sort_cmp() to maintain symmetry and transitivity
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>
Diffstat (limited to 'scripts')
| -rw-r--r-- | scripts/sorttable.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/scripts/sorttable.h b/scripts/sorttable.h index 7bd0184380d3..a7c5445baf00 100644 --- a/scripts/sorttable.h +++ b/scripts/sorttable.h @@ -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 +128,9 @@ 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->type == ORC_TYPE_UNDEFINED && orc_b->type == ORC_TYPE_UNDEFINED) + return 0; return orc_a->type == ORC_TYPE_UNDEFINED ? -1 : 1; } |