From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792678947; b=2sjvivM+mg5X0fwIdn42jok4w2A4sozLUsUlQ484stcYGLO9rvOI7TGOFQ2qZx5jYPzx GnHB6WtPpRgCil9crKbcSizGLBdrvT98hSqYARWExZd0wUm0JCZhBwZW5l814vizE88JR Rj5roFxlAD03zXDeiOeqQvSjv1bS1/GwcORT1rUthwecoKkQ4rvPCPPnmH/SI/klws6Pq M8RpOlTYk2c4zvZw1345Eh6IQD7GSSWRLu4k+V0AjXELeECq4VVrrnM+BZFi4UvfoDu+u syRGyl86U5sMsMVEJjE3XVcQZKVIIyGMlJB+DyKa3qx+snqbklin0bpvdDj3X9UbJ3Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792678947; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=5g472a3W7vVawC72w7jxU2fEzFDDELB8yS2gjaZQmsU=; b=APPYZboBv0KDuPadrRkeEjw+mPuZXuWW6G1OroNTF1KauhWG/JCVXtE67+kHVD2UIV47 rDJ57yoPJOTtaNznPOhKIBY9J6EvSzTR09GXXBw0aE62QJCehLTUaQAG1xJDdiwf706iZ rznhktRJpCQkJY7MG5SwiC/rilHN3oWrV+Av5lGIPzp4lb8Zv7terswXRxL0/lU5p3UaA 2EObZ61cL5DKSU3IM9lxBARkPufYPWNh0enE0yc2xFsj0qukdTsY+EH2cMzzagOEo+tOx t1cUWCgnlr4BjnJGibheGvgiWVTZPghq2jorXhF7QPhI+aYAfMHWzQOVFMsCuobMwEw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="JImdU/3i"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CFACF606A319 for ; Thu, 22 Oct 2026 14:22:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=JImdU/3i Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1640F1F000C1; Thu, 22 Oct 2026 14:22:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792678946; bh=5g472a3W7vVawC72w7jxU2fEzFDDELB8yS2gjaZQmsU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JImdU/3idoz7p4lOhZ7p1dofm97NKdnQ2sxbW4yCBoa8/ITessr9U8BVuSttjd6ga uWys63X3xEAd7o5k5zAF6uV42rWqpDZ3NPKu93Byp8pDoynfLCYAgGolYaMRRM9u+D 3ZpiKqbUms+Tebg5H7P+m3DtFn++pbvqvd0GJ1QVvyEH5ilvXPAGcot92lE/gWlTPp TQH73uMJSkoD5oR0JVXqtY2SNO7UoYstvBf59oE13mb0YtJT6OccIFvfjsp9qzXfUp fabLTnPq3MY6D/Gcs6GpU/TyQPnT4dHvcQDgnSCFN+K06CEeNjaStL78P3V3sSczk9 VgRBM9IzjIqPw== From: Sasha Levin To: stable@vger.kernel.org Cc: Ben Cressey , "Jose Fernandez (Anthropic)" , Mikulas Patocka , Sasha Levin Subject: [PATCH 6.6.y] dm-integrity: fix infinite loop on discard with large tag size Date: Thu, 22 Oct 2026 10:22:24 -0400 Message-ID: <20261022142214.1516335-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026102106-hacker-likely-7fd3@gregkh> References: <2026102106-hacker-likely-7fd3@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Ben Cressey [ Upstream commit 18d80c77b4c7dd20699e81cedfbbff4e9d198f28 ] When integrity_metadata handles a discard, it fills a buffer with DISCARD_FILLER and writes it over the tags, max_blocks blocks at a time. If the kmalloc fails, the buffer is the on-stack array checksums_onstack and max_size is set to HASH_MAX_DIGESTSIZE. So if the tag size is larger than HASH_MAX_DIGESTSIZE, max_blocks is zero, bi_size is never decremented and the loop never terminates. Fix this by using sizeof(checksums_onstack) as max_size. The array has MAX_TAG_SIZE bytes since commit b93b6643e9b5 ("dm integrity: fix a crash with unusually large tag size"), so max_blocks is at least 1. Fixes: 84597a44a9d8 ("dm integrity: add optional discard support") Cc: stable@vger.kernel.org Reviewed-by: Jose Fernandez (Anthropic) Signed-off-by: Ben Cressey Assisted-by: Claude:unspecified Signed-off-by: Mikulas Patocka [ sashal: Adjusted context for the absence of keyed-discard support. ] Signed-off-by: Sasha Levin --- drivers/md/dm-integrity.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c index aa6f3e71c4fa2..74cce5111637f 100644 --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -1814,7 +1814,7 @@ static void integrity_metadata(struct work_struct *w) if (unlikely(dio->op == REQ_OP_DISCARD)) { unsigned int bi_size = dio->bio_details.bi_iter.bi_size; - unsigned int max_size = likely(checksums != checksums_onstack) ? PAGE_SIZE : HASH_MAX_DIGESTSIZE; + unsigned int max_size = likely(checksums != checksums_onstack) ? PAGE_SIZE : sizeof(checksums_onstack); unsigned int max_blocks = max_size / ic->tag_size; memset(checksums, DISCARD_FILLER, max_size); -- 2.53.0