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=1792680560; b=SXK9Mjp3x3hS9+wn1OqS9iTusnv20mxslYZ32JOi/GGRFChHfT7GOikjoZqlxSTzUr4v UaWjJfeXdGIxdxAS0XMVEithcUhkwgn8jT3UG9vZkZtyxYhsvlmOGr1IbqRgke3TsLokr VoIYu+13MsbtvAv/FBlwVkjwOjhAAx3Yr2pHKH/khISlU+aKw3LY3r96NkEA/L0Fscrkb 3wQ5JbcoXHhHzKYo+rq8gE1TXqzbu6oNGnGNRwNsLcBhf6eEbFNgfF5mk+0D5GHpwBJzP LBHpLdCLByymOyV70yJIt75+w7Ow8QS6RlP7trCVV/KfWnZqmPqLKZIcGnIL/dlnNcg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792680560; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=a2e1+s/dkUyzgp4aM3yqleUClBWwjYKBUO/fowk/ZYg=; b=NmF1/qQxNdJmCpzXg4zRQ5DLkeo/Oc8BUz8PYFZbERRUfqcizpnZA2lbIyKkFFwgj5h9 0BPHmHYMKas78nWqxyf0YI34mySSneXFkmv2fJYUU0IWBxZs6BMNwVaPSmNXQQjtK4Wj0 MGVANNK3gb4nPozkZoYtjYnTxzREs2RCaY3Px/+osPfO+h3BFwyhNgaPodpYmjn946Bws 1KJZBPmx5wzjxIUCmMn2WSjQDA8J8AklG2pcmnXJ22WCIsOSTXfW28S+ESuvtHURAj1rl 4uf9dwD6T7j5FaKERyYq+FWhqry8D6vgVFFm7wud0r24xVm6q11Sqcu7DTYzEr+iaNw== 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=JK+hF4M4; 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 C6A1E60A261D for ; Thu, 22 Oct 2026 14:49:19 +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=JK+hF4M4 Received: by smtp.kernel.org (Postfix) with ESMTPSA id E20881F000C1; Thu, 22 Oct 2026 14:49:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792680559; bh=a2e1+s/dkUyzgp4aM3yqleUClBWwjYKBUO/fowk/ZYg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JK+hF4M4wH3UhteYKhWhdJWzE8u7ycD46W7iIXhml/VUxn7ESkbdrlCRf2vZqyJsW U8f34JYqwA45hA1EUn6qschMTEH/lmrPbLmSatss79pjThTKjAPayEk6eOq4vyfOZc VxmCs18e5dr67F67b88Jyr9D/WBNWvhGMqOjKugjIvxEtgCN1yZ4/NKli+tt9u8gLA Ata/scQBfWY9GZ5gtcMRu3H8lfrkJsPBDHqFrPNUa8a4r9l2+mgyKywI0+0Fra2fpW 1SFJwk3sbVEx0j9XPHW0holn9LM2jbpm0kGediFObaVULbmWwVSh47Cj778NeTHNe9 KbVY73NUbNxGA== From: Sasha Levin To: stable@vger.kernel.org Cc: Ben Cressey , "Jose Fernandez (Anthropic)" , Mikulas Patocka , Sasha Levin Subject: [PATCH 6.1.y] dm-integrity: fix infinite loop on discard with large tag size Date: Thu, 22 Oct 2026 10:49:17 -0400 Message-ID: <20261022144856.1605379-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026102106-constable-postage-e400@gregkh> References: <2026102106-constable-postage-e400@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 max_blocks calculation without extra_space. ] 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 f552c402b3c17..7988a2da6f048 100644 --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -1830,7 +1830,7 @@ 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