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authorArnd Bergmann <arnd@arndb.de>2016-11-29 12:51:04 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-11-29 20:20:07 +0100
commit5020ded78348092eac5e9909018f6d53e24eadb6 (patch)
tree6c13f132c3788411b7a8efc2ea8e24f27dfbfa3c /drivers/tty
parentf209fa03fc9d131b3108c2e4936181eabab87416 (diff)
downloadlinux-5020ded78348092eac5e9909018f6d53e24eadb6.tar.bz2
tty: nozomi: avoid sprintf buffer overflow
Testing with a gcc-7 snapshot produced an internal compiler error for this file: drivers/tty/nozomi.c: In function 'receive_flow_control': drivers/tty/nozomi.c:919:12: internal compiler error: in get_substring_ranges_for_loc, at input.c:1388 static int receive_flow_control(struct nozomi *dc) I've reported this at https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78569 but also noticed that the code line contains a stack overflow, as it prints a string into a slightly shorter fixed-length 'tmp' variable. A lot of the code here is unnecessary and can be expressed in a simpler way, relying on the fact that removing the 'DEBUG' macro will also get rid of all pr_debug() calls. This change should not change any of the output but avoids both the stack overflow and the gcc crash. The stack overflow will not happen unless a module load parameter is also set to enable the debug messages. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/nozomi.c47
1 files changed, 12 insertions, 35 deletions
diff --git a/drivers/tty/nozomi.c b/drivers/tty/nozomi.c
index e2020a691058..39b3723a32a6 100644
--- a/drivers/tty/nozomi.c
+++ b/drivers/tty/nozomi.c
@@ -63,44 +63,23 @@
#define VERSION_STRING DRIVER_DESC " 2.1d"
-/* Macros definitions */
-
/* Default debug printout level */
#define NOZOMI_DEBUG_LEVEL 0x00
-
-#define P_BUF_SIZE 128
-#define NFO(_err_flag_, args...) \
-do { \
- char tmp[P_BUF_SIZE]; \
- snprintf(tmp, sizeof(tmp), ##args); \
- printk(_err_flag_ "[%d] %s(): %s\n", __LINE__, \
- __func__, tmp); \
-} while (0)
-
-#define DBG1(args...) D_(0x01, ##args)
-#define DBG2(args...) D_(0x02, ##args)
-#define DBG3(args...) D_(0x04, ##args)
-#define DBG4(args...) D_(0x08, ##args)
-#define DBG5(args...) D_(0x10, ##args)
-#define DBG6(args...) D_(0x20, ##args)
-#define DBG7(args...) D_(0x40, ##args)
-#define DBG8(args...) D_(0x80, ##args)
-
-#ifdef DEBUG
-/* Do we need this settable at runtime? */
static int debug = NOZOMI_DEBUG_LEVEL;
+module_param(debug, int, S_IRUGO | S_IWUSR);
-#define D(lvl, args...) do \
- {if (lvl & debug) NFO(KERN_DEBUG, ##args); } \
- while (0)
-#define D_(lvl, args...) D(lvl, ##args)
-
-/* These printouts are always printed */
+/* Macros definitions */
+#define DBG_(lvl, fmt, args...) \
+do { \
+ if (lvl & debug) \
+ pr_debug("[%d] %s(): " fmt "\n", \
+ __LINE__, __func__, ##args); \
+} while (0)
-#else
-static int debug;
-#define D_(lvl, args...)
-#endif
+#define DBG1(args...) DBG_(0x01, ##args)
+#define DBG2(args...) DBG_(0x02, ##args)
+#define DBG3(args...) DBG_(0x04, ##args)
+#define DBG4(args...) DBG_(0x08, ##args)
/* TODO: rewrite to optimize macros... */
@@ -1943,7 +1922,5 @@ static __exit void nozomi_exit(void)
module_init(nozomi_init);
module_exit(nozomi_exit);
-module_param(debug, int, S_IRUGO | S_IWUSR);
-
MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION(DRIVER_DESC);