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 F280C1C03 for ; Mon, 20 Mar 2023 14:58:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7452BC433EF; Mon, 20 Mar 2023 14:58:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1679324284; bh=XyUhfPhNEkwt8xo0Wmx2PNebzxIeLjlrgrO9/ksGCQM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PNstYbmLrHbY9Lg8BK6pcciGyex6HAC15NP4eXV9Y4ZJoE25YD5KzwxobnPQoF3ZR VImuHVE9YxkFS6ioizTdAmNhSFcUMXCa9VsfeeEbyqVsE/mo0S4wj3Et7v/3ZKX0rd DylQsePC1fYjTPiqIbHhyoDrrVjlgbGjGsKwB2mg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, kernel test robot , Eric Biggers Subject: [PATCH 4.19 02/36] fs: sysfs_emit_at: Remove PAGE_SIZE alignment check Date: Mon, 20 Mar 2023 15:54:28 +0100 Message-Id: <20230320145424.287346352@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230320145424.191578432@linuxfoundation.org> References: <20230320145424.191578432@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Eric Biggers From: Eric Biggers [No upstream commit because this fixes a bug in a backport.] Before upstream commit 59bb47985c1d ("mm, sl[aou]b: guarantee natural alignment for kmalloc(power-of-two)") which went into v5.4, kmalloc did *not* always guarantee that PAGE_SIZE allocations are PAGE_SIZE-aligned. Upstream commit 2efc459d06f1 ("sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output") added two WARN()s that trigger when PAGE_SIZE allocations are not PAGE_SIZE-aligned. This was backported to old kernels that don't guarantee PAGE_SIZE alignment. Commit 10ddfb495232 ("fs: sysfs_emit: Remove PAGE_SIZE alignment check") in 4.19.y, and its equivalent in 4.14.y and 4.9.y, tried to fix this bug. However, only it handled sysfs_emit(), not sysfs_emit_at(). Fix it in sysfs_emit_at() too. A reproducer is to build the kernel with the following options: CONFIG_SLUB=y CONFIG_SLUB_DEBUG=y CONFIG_SLUB_DEBUG_ON=y CONFIG_PM=y CONFIG_SUSPEND=y CONFIG_PM_WAKELOCKS=y Then run: echo foo > /sys/power/wake_lock && cat /sys/power/wake_lock Fixes: cb1f69d53ac8 ("sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output") Reported-by: kernel test robot Link: https://lore.kernel.org/r/202303141634.1e64fd76-yujie.liu@intel.com Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -599,7 +599,7 @@ int sysfs_emit_at(char *buf, int at, con va_list args; int len; - if (WARN(!buf || offset_in_page(buf) || at < 0 || at >= PAGE_SIZE, + if (WARN(!buf || at < 0 || at >= PAGE_SIZE, "invalid sysfs_emit_at: buf:%p at:%d\n", buf, at)) return 0;