linux-kernel - [PATCH v2 -next] PCI: Don't use GFP_KERNEL for kstrbdup in resource_alignment

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190903082229.21488-1-yuehaibing@huawei.com>
Date:   Tue, 3 Sep 2019 16:22:29 +0800
From:   YueHaibing <yuehaibing@...wei.com>
To:     <bhelgaas@...gle.com>, <hch@...radead.org>
CC:     <linux-pci@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        YueHaibing <yuehaibing@...wei.com>
Subject: [PATCH v2 -next] PCI: Don't use GFP_KERNEL for kstrbdup in resource_alignment_store

When allocating memory, the GFP_KERNEL cannot be used during the
spin_lock period. It may cause scheduling when holding spin_lock.

Suggested-by: Christoph Hellwig <hch@...radead.org>
Fixes: f13755318675 ("PCI: Move pci_[get|set]_resource_alignment_param() into their callers")
Signed-off-by: YueHaibing <yuehaibing@...wei.com>
---
v2: move alloc out of spinlock
---
 drivers/pci/pci.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 484e353..a3d5920 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -6145,14 +6145,17 @@ static ssize_t resource_alignment_show(struct bus_type *bus, char *buf)
 static ssize_t resource_alignment_store(struct bus_type *bus,
 					const char *buf, size_t count)
 {
-	spin_lock(&resource_alignment_lock);
+	char *param = kstrndup(buf, count, GFP_KERNEL);
 
-	kfree(resource_alignment_param);
-	resource_alignment_param = kstrndup(buf, count, GFP_KERNEL);
+	if (!param)
+		return -ENOMEM;
 
+	spin_lock(&resource_alignment_lock);
+	kfree(resource_alignment_param);
+	resource_alignment_param = param;
 	spin_unlock(&resource_alignment_lock);
 
-	return resource_alignment_param ? count : -ENOMEM;
+	return count;
 }
 
 static BUS_ATTR_RW(resource_alignment);
-- 
2.7.4