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Subject[PATCH AUTOSEL 5.11 41/52] PCI: Fix pci_register_io_range() memory leak
Date
From: Geert Uytterhoeven <geert+renesas@glider.be>

[ Upstream commit f6bda644fa3a7070621c3bf12cd657f69a42f170 ]

Kmemleak reports:

unreferenced object 0xc328de40 (size 64):
comm "kworker/1:1", pid 21, jiffies 4294938212 (age 1484.670s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 e0 d8 fc eb 00 00 00 00 ................
00 00 10 fe 00 00 00 00 00 00 00 00 00 00 00 00 ................

backtrace:
[<ad758d10>] pci_register_io_range+0x3c/0x80
[<2c7f139e>] of_pci_range_to_resource+0x48/0xc0
[<f079ecc8>] devm_of_pci_get_host_bridge_resources.constprop.0+0x2ac/0x3ac
[<e999753b>] devm_of_pci_bridge_init+0x60/0x1b8
[<a895b229>] devm_pci_alloc_host_bridge+0x54/0x64
[<e451ddb0>] rcar_pcie_probe+0x2c/0x644

In case a PCI host driver's probe is deferred, the same I/O range may be
allocated again, and be ignored, causing a memory leak.

Fix this by (a) letting logic_pio_register_range() return -EEXIST if the
passed range already exists, so pci_register_io_range() will free it, and
by (b) making pci_register_io_range() not consider -EEXIST an error
condition.

Link: https://lore.kernel.org/r/20210202100332.829047-1-geert+renesas@glider.be
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pci/pci.c | 4 ++++
lib/logic_pio.c | 3 +++
2 files changed, 7 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 790393d1e318..a53e25d75d04 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4022,6 +4022,10 @@ int pci_register_io_range(struct fwnode_handle *fwnode, phys_addr_t addr,
ret = logic_pio_register_range(range);
if (ret)
kfree(range);
+
+ /* Ignore duplicates due to deferred probing */
+ if (ret == -EEXIST)
+ ret = 0;
#endif

return ret;
diff --git a/lib/logic_pio.c b/lib/logic_pio.c
index f32fe481b492..07b4b9a1f54b 100644
--- a/lib/logic_pio.c
+++ b/lib/logic_pio.c
@@ -28,6 +28,8 @@ static DEFINE_MUTEX(io_range_mutex);
* @new_range: pointer to the IO range to be registered.
*
* Returns 0 on success, the error code in case of failure.
+ * If the range already exists, -EEXIST will be returned, which should be
+ * considered a success.
*
* Register a new IO range node in the IO range list.
*/
@@ -51,6 +53,7 @@ int logic_pio_register_range(struct logic_pio_hwaddr *new_range)
list_for_each_entry(range, &io_range_list, list) {
if (range->fwnode == new_range->fwnode) {
/* range already there */
+ ret = -EEXIST;
goto end_register;
}
if (range->flags == LOGIC_PIO_CPU_MMIO &&
--
2.30.1
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