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 9BEC62FF16C; Wed, 10 Dec 2025 07:36:03 +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=1765352163; cv=none; b=pycbLux4k7RAiOTaHG6FvyJHMIgJvNWTjCrbSy7WGhOuku1xJ7WG/uQhNyTo+H275/4ba6Q2R7adEeScdRrrKbLwiK0OSpiZXG1buaVN1TlpdLQOcwxzPHyAoWEmZdiyyu0vRNE81tf0IrrREGliBohrRSACunaTuc02u7dBJgA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765352163; c=relaxed/simple; bh=ekPyhSUzDrvz4KRBkNTx+0j2+2Im1+eNtSKUM/CTiwg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RRMwq5RsxGTQ2Ay9caRzyoZn2+F+0W3Yg7WEnEL7C/fOBmmFEeMmHkHNq3O1zq2zOXcDIphhlIVEQcmre5WPOQhHSt8K1gYWwWLXH6DRGLGttx8bZWcIPA9FWpiGPHL0FjUvHtdPZV3pcNPGKwAy/dI7BULBAGIp9Rn8a9F5rxU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=zjp0QkzQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="zjp0QkzQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 42294C4CEF1; Wed, 10 Dec 2025 07:36:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1765352163; bh=ekPyhSUzDrvz4KRBkNTx+0j2+2Im1+eNtSKUM/CTiwg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zjp0QkzQssOveq89Qgayw8LlouZt/oVJQCIP7eLsgFi2g/NSv885gGQ2L/OmlB4T8 dZ2H+W342vUby7aFSHlQOM35NbhhXfuvYLdGHlPFaPoVVwqIgCUZzdxi1cZETRHSC6 QOjzvsCMAKFkfCctqJklfuJwDKKi0DZG0SRcf9Rs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Giovanni Cabiddu , Suman Kumar Chakraborty , Herbert Xu Subject: [PATCH 6.18 06/29] crypto: zstd - fix double-free in per-CPU stream cleanup Date: Wed, 10 Dec 2025 16:30:16 +0900 Message-ID: <20251210072944.542909790@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251210072944.363788552@linuxfoundation.org> References: <20251210072944.363788552@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Giovanni Cabiddu commit 48bc9da3c97c15f1ea24934bcb3b736acd30163d upstream. The crypto/zstd module has a double-free bug that occurs when multiple tfms are allocated and freed. The issue happens because zstd_streams (per-CPU contexts) are freed in zstd_exit() during every tfm destruction, rather than being managed at the module level. When multiple tfms exist, each tfm exit attempts to free the same shared per-CPU streams, resulting in a double-free. This leads to a stack trace similar to: BUG: Bad page state in process kworker/u16:1 pfn:106fd93 page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106fd93 flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff) page_type: 0xffffffff() raw: 0017ffffc0000000 dead000000000100 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: nonzero entire_mapcount Modules linked in: ... CPU: 3 UID: 0 PID: 2506 Comm: kworker/u16:1 Kdump: loaded Tainted: G B Hardware name: ... Workqueue: btrfs-delalloc btrfs_work_helper Call Trace: dump_stack_lvl+0x5d/0x80 bad_page+0x71/0xd0 free_unref_page_prepare+0x24e/0x490 free_unref_page+0x60/0x170 crypto_acomp_free_streams+0x5d/0xc0 crypto_acomp_exit_tfm+0x23/0x50 crypto_destroy_tfm+0x60/0xc0 ... Change the lifecycle management of zstd_streams to free the streams only once during module cleanup. Fixes: f5ad93ffb541 ("crypto: zstd - convert to acomp") Cc: stable@vger.kernel.org Signed-off-by: Giovanni Cabiddu Reviewed-by: Suman Kumar Chakraborty Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- crypto/zstd.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) --- a/crypto/zstd.c +++ b/crypto/zstd.c @@ -75,11 +75,6 @@ static int zstd_init(struct crypto_acomp return ret; } -static void zstd_exit(struct crypto_acomp *acomp_tfm) -{ - crypto_acomp_free_streams(&zstd_streams); -} - static int zstd_compress_one(struct acomp_req *req, struct zstd_ctx *ctx, const void *src, void *dst, unsigned int *dlen) { @@ -297,7 +292,6 @@ static struct acomp_alg zstd_acomp = { .cra_module = THIS_MODULE, }, .init = zstd_init, - .exit = zstd_exit, .compress = zstd_compress, .decompress = zstd_decompress, }; @@ -310,6 +304,7 @@ static int __init zstd_mod_init(void) static void __exit zstd_mod_fini(void) { crypto_unregister_acomp(&zstd_acomp); + crypto_acomp_free_streams(&zstd_streams); } module_init(zstd_mod_init);