+ lib-bch-fix-signed-shift-overflow-in-build_mod8_tables.patch added to mm-nonmm-unstable branch

+ lib-bch-fix-signed-shift-overflow-in-build_mod8_tables.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: lib/bch: fix signed shift overflow in build_mod8_tables
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     lib-bch-fix-signed-shift-overflow-in-build_mod8_tables.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-bch-fix-signed-shift-overflow-in-build_mod8_tables.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Josh Law <objecting@objecting.org>
Subject: lib/bch: fix signed shift overflow in build_mod8_tables
Date: Wed, 18 Mar 2026 07:48:06 +0000

Cast loop variable to unsigned int before left-shifting to avoid undefined
behavior when i >= 128 and b == 3 (i << 24 overflows signed int).

Link: https://lkml.kernel.org/r/20260318074806.16527-3-objecting@objecting.org
Signed-off-by: Josh Law <objecting@objecting.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ivan Djelic <ivan.djelic@parrot.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/bch.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/lib/bch.c~lib-bch-fix-signed-shift-overflow-in-build_mod8_tables
+++ a/lib/bch.c
@@ -1116,7 +1116,7 @@ static void build_mod8_tables(struct bch
 		for (b = 0; b < 4; b++) {
 			/* we want to compute (p(X).X^(8*b+deg(g))) mod g(X) */
 			tab = bch->mod8_tab + (b*256+i)*l;
-			data = i << (8*b);
+			data = (unsigned int)i << (8*b);
 			while (data) {
 				d = deg(data);
 				/* subtract X^d.g(X) from p(X).X^(8*b+deg(g)) */
_

Patches currently in -mm which might be from objecting@objecting.org are

lib-maple_tree-fix-swapped-arguments-in-mas_safe_pivot-call.patch
lib-glob-fix-grammar-and-replace-non-inclusive-terminology.patch
lib-glob-add-explicit-include-for-exporth.patch
lib-glob-replace-bitwise-or-with-logical-operation-on-boolean.patch
lib-glob-clean-up-bool-abuse-in-pointer-arithmetic.patch
lib-uuid-fix-typo-reversion-to-revision-in-comment.patch
lib-inflate-fix-memory-leak-in-inflate_fixed-on-inflate_codes-failure.patch
lib-inflate-fix-memory-leak-in-inflate_dynamic-on-inflate_codes-failure.patch
lib-inflate-fix-grammar-in-comment-variable-to-variables.patch
lib-inflate-fix-typo-this-results-to-the-results-in-comment.patch
lib-bug-fix-inconsistent-capitalization-in-bug-message.patch
lib-bug-remove-unnecessary-variable-initializations.patch
lib-idr-fix-ida_find_first_range-missing-ids-across-chunk-boundaries.patch
lib-decompress_bunzip2-fix-32-bit-shift-undefined-behavior.patch
lib-ts_bm-fix-integer-overflow-in-pattern-length-calculation.patch
lib-ts_kmp-fix-integer-overflow-in-pattern-length-calculation.patch
lib-glob-initialize-back_str-to-silence-uninitialized-variable-warning.patch
lib-bch-fix-signed-left-shift-undefined-behavior.patch
lib-bch-fix-signed-shift-overflow-in-build_mod8_tables.patch