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| author | Kuan-Wei Chiu <visitorckw@gmail.com> | 2024-09-28 19:36:08 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-02-17 10:04:46 +0100 |
| commit | 404e5fd918a0b14abec06c7eca128f04c9b98e41 (patch) | |
| tree | d1f8cfce99ade0125c3cfc3cd2abca89e074641f /kernel | |
| parent | 0412bca906d598b0a60c0da837dadb036a95db84 (diff) | |
| download | linux-404e5fd918a0b14abec06c7eca128f04c9b98e41.tar.gz linux-404e5fd918a0b14abec06c7eca128f04c9b98e41.tar.bz2 linux-404e5fd918a0b14abec06c7eca128f04c9b98e41.zip | |
printk: Fix signed integer overflow when defining LOG_BUF_LEN_MAX
[ Upstream commit 3d6f83df8ff2d5de84b50377e4f0d45e25311c7a ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/printk/printk.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 7530df62ff7c..3b75f6e8410b 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -523,7 +523,7 @@ 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; |