ata: libata-core: fix NULL pointer deref in ata_host_alloc_pinfo()

In an unlikely (and probably wrong?) case that the 'ppi' parameter of
ata_host_alloc_pinfo() points to an array starting with a NULL pointer,
there's going to be a kernel oops as the 'pi' local variable won't get
reassigned from the initial value of NULL. Initialize 'pi' instead to
'&ata_dummy_port_info' to fix the possible kernel oops for good...

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.

Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 40e816419f48c75d57930abccc015948c1c2551b..c214ff928e452fdb7113c334b9d235512cb4a286 100644 (file)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5462,7 +5462,7 @@ struct ata_host *ata_host_alloc_pinfo(struct device *dev,
                                      const struct ata_port_info * const * ppi,
                                      int n_ports)
 {
-       const struct ata_port_info *pi;
+       const struct ata_port_info *pi = &ata_dummy_port_info;
        struct ata_host *host;
        int i, j;
 
@@ -5470,7 +5470,7 @@ struct ata_host *ata_host_alloc_pinfo(struct device *dev,
        if (!host)
                return NULL;
 
-       for (i = 0, j = 0, pi = NULL; i < host->n_ports; i++) {
+       for (i = 0, j = 0; i < host->n_ports; i++) {
                struct ata_port *ap = host->ports[i];
 
                if (ppi[j])