[PATCH 06/11] staging: gasket: page table: fixup error path allocating coherent mem

From: Todd Poynor
Date: Mon Oct 15 2018 - 01:00:07 EST


From: Nick Ewalt <nicholasewalt@xxxxxxxxxx>

Correctly clean up data structure state in gasket_alloc_coherent_memory
error path, to ensure no double free on the stale pointer value.

Signed-off-by: Nick Ewalt <nicholasewalt@xxxxxxxxxx>
Signed-off-by: Todd Poynor <toddpoynor@xxxxxxxxxx>
---
drivers/staging/gasket/gasket_page_table.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/gasket/gasket_page_table.c b/drivers/staging/gasket/gasket_page_table.c
index 9c2f8671216b5..a88f2ae0cee8b 100644
--- a/drivers/staging/gasket/gasket_page_table.c
+++ b/drivers/staging/gasket/gasket_page_table.c
@@ -1332,9 +1332,13 @@ int gasket_alloc_coherent_memory(struct gasket_dev *gasket_dev, u64 size,
return 0;

nomem:
- if (mem)
+ if (mem) {
dma_free_coherent(gasket_get_device(gasket_dev),
num_pages * PAGE_SIZE, mem, handle);
+ gasket_dev->coherent_buffer.length_bytes = 0;
+ gasket_dev->coherent_buffer.virt_base = NULL;
+ gasket_dev->coherent_buffer.phys_base = 0;
+ }

kfree(gasket_dev->page_table[index]->coherent_pages);
gasket_dev->page_table[index]->coherent_pages = NULL;
--
2.19.0.605.g01d371f741-goog