usb: early: xhci-dbc: Fix xdbc number parsing

kstrtoul() assumes the string contains the number only and is \0
terminated, this is not the case, as such things like:

	earlyprintk=xdbc1,keep

go completely sideways. Use simple_strtoul() instead.

Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220304152136.035911620@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
index 100a45d..bfb7e2b 100644 (file)
--- a/drivers/usb/early/xhci-dbc.c
+++ b/drivers/usb/early/xhci-dbc.c
@@ -603,6 +603,7 @@ int __init early_xdbc_parse_parameter(char *s, int keep_early)
 {
        unsigned long dbgp_num = 0;
        u32 bus, dev, func, offset;
+       char *e;
        int ret;
 
        if (!early_pci_allowed())
@@ -613,8 +614,11 @@ int __init early_xdbc_parse_parameter(char *s, int keep_early)
        if (xdbc.xdbc_reg)
                return 0;
 
-       if (*s && kstrtoul(s, 0, &dbgp_num))
-               dbgp_num = 0;
+       if (*s) {
+              dbgp_num = simple_strtoul(s, &e, 10);
+              if (s == e)
+                      dbgp_num = 0;
+       }
 
        pr_notice("dbgp_num: %lu\n", dbgp_num);