[+cc Sergey, Alex, Krzysztof since you all posted similar patches in the past]
On Fri, Oct 07, 2022 at 09:07:35AM +0200, Sascha Hauer wrote:
On Fri, Oct 07, 2022 at 08:56:18AM +0200, Sascha Hauer wrote:
When pci_create_attr() fails then pci_remove_resource_files() is called which will iterate over the res_attr[_wc] arrays and frees every non NULL entry. To avoid a double free here we have to set the failed entry to NULL in pci_create_attr() when freeing it.
You might consider applying this alternative version instead which IMO looks a bit better.
Thanks, I agree, I like how this one doesn't set res_attr[] until we know we're going to return success.
Applied to pci/sysfs for v6.2, thanks!
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From fe8e0e6f914c14395c751b7dc165967b12427995 Mon Sep 17 00:00:00 2001 From: Sascha Hauer s.hauer@pengutronix.de Date: Fri, 7 Oct 2022 07:35:35 +0200 Subject: [PATCH] PCI/sysfs: Fix double free in error path
When pci_create_attr() fails then pci_remove_resource_files() is called which will iterate over the res_attr[_wc] arrays and frees every non NULL entry. To avoid a double free here set the array entry only after it's clear we successfully initialized it.
Fixes: b562ec8f74e4 ("PCI: Don't leak memory if sysfs_create_bin_file() fails") Signed-off-by: Sascha Hauer s.hauer@pengutronix.de Cc: stable@vger.kernel.org
drivers/pci/pci-sysfs.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index fc804e08e3cb5..6dd4050c9f2ed 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1174,11 +1174,9 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine) sysfs_bin_attr_init(res_attr); if (write_combine) {
pdev->res_attr_wc[num] = res_attr;pdev->res_attr[num] = res_attr;@@ -1196,10 +1194,17 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine) res_attr->size = pci_resource_len(pdev, num); res_attr->private = (void *)(unsigned long)num; retval = sysfs_create_bin_file(&pdev->dev.kobj, res_attr);
- if (retval)
- if (retval) { kfree(res_attr);
return retval;- }
- if (write_combine)
pdev->res_attr_wc[num] = res_attr;- else
pdev->res_attr[num] = res_attr;
- return retval;
- return 0;
} /** -- 2.30.2
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