Re: [PATCH v2] ocxl: fix pci device refcount leak when calling get_function_0()
From: Frederic Barrat <hidden>
Date: 2022-11-24 08:11:44
On 21/11/2022 16:43, Yang Yingliang wrote:
get_function_0() calls pci_get_domain_bus_and_slot(), as comment
says, it returns a pci device with refcount increment, so after
using it, pci_dev_put() needs be called.
Get the device reference when get_function_0() is not called, so
pci_dev_put() can be called in the error path and callers
unconditionally. And add comment above get_dvsec_vendor0() to tell
callers to call pci_dev_put().
Fixes: 87db7579ebd5 ("ocxl: control via sysfs whether the FPGA is reloaded on a link reset")
Suggested-by: Andrew Donnellan <redacted>
Signed-off-by: Yang Yingliang <redacted>
---Thanks for fixing it! Acked-by: Frederic Barrat <redacted> Fred
quoted hunk ↗ jump to hunk
v1 -> v2: Add comment above get_dvsec_vendor0(). Get reference where dev is function 0, and call pci_dev_put() unconditionally in callers. --- drivers/misc/ocxl/config.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-)diff --git a/drivers/misc/ocxl/config.c b/drivers/misc/ocxl/config.c index e401a51596b9..92ab49705f64 100644 --- a/drivers/misc/ocxl/config.c +++ b/drivers/misc/ocxl/config.c@@ -193,6 +193,18 @@ static int read_dvsec_vendor(struct pci_dev *dev) return 0; } +/** + * get_dvsec_vendor0() - Find a related PCI device (function 0) + * @dev: PCI device to match + * @dev0: The PCI device (function 0) found + * @out_pos: The position of PCI device (function 0) + * + * Returns 0 on success, negative on failure. + * + * NOTE: If it's successful, the reference of dev0 is increased, + * so after using it, the callers must call pci_dev_put() to give + * up the reference. + */ static int get_dvsec_vendor0(struct pci_dev *dev, struct pci_dev **dev0, int *out_pos) {@@ -202,10 +214,14 @@ static int get_dvsec_vendor0(struct pci_dev *dev, struct pci_dev **dev0, dev = get_function_0(dev); if (!dev) return -1; + } else { + dev = pci_dev_get(dev); } pos = find_dvsec(dev, OCXL_DVSEC_VENDOR_ID); - if (!pos) + if (!pos) { + pci_dev_put(dev); return -1; + } *dev0 = dev; *out_pos = pos; return 0;@@ -222,6 +238,7 @@ int ocxl_config_get_reset_reload(struct pci_dev *dev, int *val) pci_read_config_dword(dev0, pos + OCXL_DVSEC_VENDOR_RESET_RELOAD, &reset_reload); + pci_dev_put(dev0); *val = !!(reset_reload & BIT(0)); return 0; }@@ -243,6 +260,7 @@ int ocxl_config_set_reset_reload(struct pci_dev *dev, int val) reset_reload &= ~BIT(0); pci_write_config_dword(dev0, pos + OCXL_DVSEC_VENDOR_RESET_RELOAD, reset_reload); + pci_dev_put(dev0); return 0; }