From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3170C3E5EFF for ; Wed, 18 Mar 2026 19:08:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773860898; cv=none; b=bQ9ZQmrOJ4puikTbr39shLcSLaINX87RYUJZ/yau2AwQe0/oZFQRMKOCDfpwormMUSoEAvhBPiCVN9iKgyoPck63t1tmepy4fqY9gTFzHZDiMghRJXIdXQakC2i0iMVo0NwP2Y75SeBstZaFlB35skA0QPpGmFDeg6pO42mYa4U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773860898; c=relaxed/simple; bh=D7gYURAJU5+7QTSoIs6F0HbiMgUTwl4Wm3nOesNUXOc=; h=Date:To:From:Subject:Message-Id; b=V0p84goY7sIkMZo8kvkUfy0MGAU2uuwGeK0iVX6XbAPGkIRS1HCDmZKDxJ/A2iuDK3BLHpyM7cuXrKSZbSLf95ClG38fmHIbkO7CHWymXP4XDZEi9bGSHaBAGlouY8IleEvbOtOUBIMFH5JzWNffmQCacAyAO2TK3IrIxeKmHqs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=SxBzuntE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="SxBzuntE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C57B3C19421; Wed, 18 Mar 2026 19:08:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1773860897; bh=D7gYURAJU5+7QTSoIs6F0HbiMgUTwl4Wm3nOesNUXOc=; h=Date:To:From:Subject:From; b=SxBzuntEyOSa7TRtHubsz4RrS0NnHD0wwXuEAr0s88pUdJ8YNha/QnEJkGlScVX02 AFQOehbFGuVyxE5dwS9zDrn7tHi5wYLiJJOokgd6vMwNw+qEX8Dyo+6jd5Kqn083Ty /DIsYyzQDHw9ewEORlC74p13cL7RVQXrz8zyZ9lQ= Date: Wed, 18 Mar 2026 12:08:17 -0700 To: mm-commits@vger.kernel.org,ivan.djelic@parrot.com,akpm@linux-foundation.org,objecting@objecting.org,akpm@linux-foundation.org From: Andrew Morton Subject: + lib-bch-fix-signed-left-shift-undefined-behavior.patch added to mm-nonmm-unstable branch Message-Id: <20260318190817.C57B3C19421@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: lib/bch: fix signed left-shift undefined behavior has been added to the -mm mm-nonmm-unstable branch. Its filename is lib-bch-fix-signed-left-shift-undefined-behavior.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-left-shift-undefined-behavior.patch This patch will later appear in the mm-nonmm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Josh Law Subject: lib/bch: fix signed left-shift undefined behavior Date: Wed, 18 Mar 2026 07:48:05 +0000 Patch series "lib/bch: fix undefined behavior from signed left-shifts". Fix two instances of undefined behavior in lib/bch.c caused by left-shifting signed integers into or past the sign bit. While the kernel's -fno-strict-overflow flag prevents miscompilation today, these are formally UB per C11 6.5.7p4 and trivial to fix. This patch (of 2): Use 1u instead of 1 to avoid undefined behavior when left-shifting into the sign bit of a signed int. deg() can return up to 31, and 1 << 31 is UB per C11. Link: https://lkml.kernel.org/r/20260318074806.16527-2-objecting@objecting.org Signed-off-by: Josh Law Reviewed-by: Andrew Morton Cc: Ivan Djelic Signed-off-by: Andrew Morton --- lib/bch.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/lib/bch.c~lib-bch-fix-signed-left-shift-undefined-behavior +++ a/lib/bch.c @@ -392,7 +392,7 @@ static void compute_syndromes(struct bch for (j = 0; j < 2*t; j += 2) syn[j] ^= a_pow(bch, (j+1)*(i+s)); - poly ^= (1 << i); + poly ^= (1u << i); } } while (s > 0); @@ -612,7 +612,7 @@ static int find_poly_deg2_roots(struct b while (v) { i = deg(v); r ^= bch->xi_tab[i]; - v ^= (1 << i); + v ^= (1u << i); } /* verify root */ if ((gf_sqr(bch, r)^r) == u) { _ 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