From: Kuan-Wei Chiu <visitorckw@gmail.com> mainline inclusion from mainline-v6.14-rc1 commit 3d6f83df8ff2d5de84b50377e4f0d45e25311c7a category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBQPCU Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Shifting 1 << 31 on a 32-bit int causes signed integer overflow, which leads to undefined behavior. To prevent this, cast 1 to u32 before performing the shift, ensuring well-defined behavior. This change explicitly avoids any potential overflow by ensuring that the shift occurs on an unsigned 32-bit integer. Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com> Acked-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20240928113608.1438087-1-visitorckw@gmail.com Signed-off-by: Petr Mladek <pmladek@suse.com> Conflicts: kernel/printk/printk.c [Fix context conflicts.] Signed-off-by: Xiaomeng Zhang <zhangxiaomeng13@huawei.com> --- kernel/printk/printk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index f6b48484a300..8d324657bbda 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -476,7 +476,7 @@ static struct latched_seq clear_seq = { /* record buffer */ #define LOG_ALIGN __alignof__(unsigned long) #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) -#define LOG_BUF_LEN_MAX (u32)(1 << 31) +#define LOG_BUF_LEN_MAX ((u32)1 << 31) static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); static char *log_buf = __log_buf; static u32 log_buf_len = __LOG_BUF_LEN; -- 2.34.1