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authorNathan Chancellor <natechancellor@gmail.com>2020-01-30 15:16:44 -0700
committerPetr Mladek <pmladek@suse.com>2020-02-11 13:01:00 +0100
commit5661dd95a2958634485bb1a53f90a6ab621d4b0c (patch)
tree84d284668a4b97f8be8a83e36ce2206d7e1d30a7 /kernel/printk
parenta4fe2b4d87c9f2298ae6a641a7a64bc941d079d0 (diff)
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printk: Convert a use of sprintf to snprintf in console_unlock
When CONFIG_PRINTK is disabled (e.g. when building allnoconfig), clang warns: ../kernel/printk/printk.c:2416:10: warning: 'sprintf' will always overflow; destination buffer has size 0, but format string expands to at least 33 [-Wfortify-source] len = sprintf(text, ^ 1 warning generated. It is not wrong; text has a zero size when CONFIG_PRINTK is disabled because LOG_LINE_MAX and PREFIX_MAX are both zero. Change to snprintf so that this case is explicitly handled without any risk of overflow. Link: https://github.com/ClangBuiltLinux/linux/issues/846 Link: https://github.com/llvm/llvm-project/commit/6d485ff455ea2b37fef9e06e426dae6c1241b231 Link: http://lkml.kernel.org/r/20200130221644.2273-1-natechancellor@gmail.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-kernel@vger.kernel.org Cc: clang-built-linux@googlegroups.com Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'kernel/printk')
-rw-r--r--kernel/printk/printk.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index fada22dc4ab6..a44094727a5c 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2413,9 +2413,9 @@ again:
printk_safe_enter_irqsave(flags);
raw_spin_lock(&logbuf_lock);
if (console_seq < log_first_seq) {
- len = sprintf(text,
- "** %llu printk messages dropped **\n",
- log_first_seq - console_seq);
+ len = snprintf(text, sizeof(text),
+ "** %llu printk messages dropped **\n",
+ log_first_seq - console_seq);
/* messages are gone, move to first one */
console_seq = log_first_seq;