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 40ACA12FB31; Wed, 19 Jun 2024 13:03:22 +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=1718802202; cv=none; b=qFJedGUmNDFlV0R21wiM5pbvryknNgnjLzCRxTHcKJ3IunXufuyKqoxcdtWIijlpMH0dVREuXk5eXxfm7DJLiR+NQHUbcHtIzwSiEivDHfX5NY9R3q+7DU6gUmXE2I9MftAEJF5EP3QYscCHc8ZfMLTarH5wpxNPdYEsTKI/PfI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718802202; c=relaxed/simple; bh=yf0vl1x5dNyfp2npKzq0OpDpjDTyP3WsJ65vAdqzRFA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=G9z51KVT2yJHuGswZ1J6p2CaJOQrY8G1TCUhowZZxjKhbjEeUUxzd8jYcF+V8yxYSxO/ofTGVYM8c8tWhSyWElMVXzdNeDzxzWFj8xczk0ukh33yBTily64C58gYosyDKrZbi2bR/Qfblt5P/ldzOJZhhgjkpwe2b/56ZIlg+to= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fXbgmSvK; 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="fXbgmSvK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BCCA7C2BBFC; Wed, 19 Jun 2024 13:03:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718802202; bh=yf0vl1x5dNyfp2npKzq0OpDpjDTyP3WsJ65vAdqzRFA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fXbgmSvKKY0vA8e2/d6+E2HE0MlH7jyCRBR9SpAYBY9tOTlUcbSxq3V3X/91kuJPP c3DRMfQm2kWf6APDzpaY3qHEJ4H+Y35xGW9jdIar2BH6T5KGIQRB5jHRwcEINoRy1y EGbqlSgNIqybHeDRH3dqGe5vkBpaPRUwQn8sq0Ro= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Baokun Li , Jeff Layton , Christian Brauner , Sasha Levin Subject: [PATCH 6.6 115/267] cachefiles: flush all requests after setting CACHEFILES_DEAD Date: Wed, 19 Jun 2024 14:54:26 +0200 Message-ID: <20240619125610.764860715@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240619125606.345939659@linuxfoundation.org> References: <20240619125606.345939659@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baokun Li [ Upstream commit 85e833cd7243bda7285492b0653c3abb1e2e757b ] In ondemand mode, when the daemon is processing an open request, if the kernel flags the cache as CACHEFILES_DEAD, the cachefiles_daemon_write() will always return -EIO, so the daemon can't pass the copen to the kernel. Then the kernel process that is waiting for the copen triggers a hung_task. Since the DEAD state is irreversible, it can only be exited by closing /dev/cachefiles. Therefore, after calling cachefiles_io_error() to mark the cache as CACHEFILES_DEAD, if in ondemand mode, flush all requests to avoid the above hungtask. We may still be able to read some of the cached data before closing the fd of /dev/cachefiles. Note that this relies on the patch that adds reference counting to the req, otherwise it may UAF. Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie") Signed-off-by: Baokun Li Link: https://lore.kernel.org/r/20240522114308.2402121-12-libaokun@huaweicloud.com Acked-by: Jeff Layton Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin --- fs/cachefiles/daemon.c | 2 +- fs/cachefiles/internal.h | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index 26b487e112596..b9945e4f697be 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -133,7 +133,7 @@ static int cachefiles_daemon_open(struct inode *inode, struct file *file) return 0; } -static void cachefiles_flush_reqs(struct cachefiles_cache *cache) +void cachefiles_flush_reqs(struct cachefiles_cache *cache) { struct xarray *xa = &cache->reqs; struct cachefiles_req *req; diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index 28799c8e2c6f6..3eea52462fc87 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -188,6 +188,7 @@ extern int cachefiles_has_space(struct cachefiles_cache *cache, * daemon.c */ extern const struct file_operations cachefiles_daemon_fops; +extern void cachefiles_flush_reqs(struct cachefiles_cache *cache); extern void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache); extern void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache); @@ -414,6 +415,8 @@ do { \ pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__); \ fscache_io_error((___cache)->cache); \ set_bit(CACHEFILES_DEAD, &(___cache)->flags); \ + if (cachefiles_in_ondemand_mode(___cache)) \ + cachefiles_flush_reqs(___cache); \ } while (0) #define cachefiles_io_error_obj(object, FMT, ...) \ -- 2.43.0