Fixes an oops found while testing the stm32_pcie ep driver with handling
of PERST# deassertion:
[ 92.154549] ------------[ cut here ]------------
[ 92.159093] Trying to vunmap() nonexistent vm area (0000000031e0f06f)
...
[ 92.288763] vunmap+0x58/0x60 (P)
[ 92.292096] dma_direct_free+0x88/0x18c
[ 92.295932] dma_free_attrs+0x84/0xf8
[ 92.299664] pci_epf_free_space+0x48/0x78
[ 92.303698] pci_epf_test_epc_init+0x184/0x3c0 [pci_epf_test]
[ 92.309446] pci_epc_init_notify+0x70/0xb4
[ 92.313578] stm32_pcie_ep_perst_irq_thread+0xf8/0x24c
...
During EP initialization, pci_epf_test_alloc_space allocates all BARs,
which are further freed if epc_set_bar fails (for instance, due to
no free inbound window).
However, when pci_epc_set_bar fails, the error path:
pci_epc_set_bar -> pci_epf_free_space
does not reset epf_test->reg[bar].
Then, if the host reboots, PERST# deassertion restarts the BAR allocation
sequence with the same allocation failure (no free inbound window).
So, two subsequent calls to the sequence:
if (!epf_test->reg[bar])
continue;
ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, &epf->bar[bar]);
if (ret) {
pci_epf_free_space(epf, epf_test->reg[bar], bar, PRIMARY_INTERFACE);
}
create a double free situation since epf_test->reg[bar] was deallocated
and is still non-NULL.
This patch makes pci_epf_alloc_space/pci_epf_free_space symmetric
by resetting epf_test->reg[bar] when memory is deallocated.
Signed-off-by: Christian Bruel <christian.bruel@xxxxxxxxxxx>
---
drivers/pci/endpoint/functions/pci-epf-test.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index ffb534a8e50a..b29e938ee16a 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -718,6 +718,7 @@ static int pci_epf_test_set_bar(struct pci_epf *epf)
if (ret) {
pci_epf_free_space(epf, epf_test->reg[bar], bar,
PRIMARY_INTERFACE);
+ epf_test->reg[bar] = NULL;
dev_err(dev, "Failed to set BAR%d\n", bar);
if (bar == test_reg_bar)
return ret;
@@ -909,6 +910,7 @@ static void pci_epf_test_free_space(struct pci_epf *epf)
pci_epf_free_space(epf, epf_test->reg[bar], bar,
PRIMARY_INTERFACE);
+ epf_test->reg[bar] = NULL;
}
}
--
2.34.1
