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| author | Dmitriy Alexandrov <d06alexandrov@users.noreply.github.com> | 2023-06-08 09:08:46 +0000 |
|---|---|---|
| committer | Cy Schubert <cy@FreeBSD.org> | 2023-06-09 21:04:54 +0000 |
| commit | af9ce4e9bb7d717279e02d46455e85ef6fb828f7 (patch) | |
| tree | 37b602f356a568ee1fe1ac226a2a431888af8db9 | |
| parent | 2c01176a2802cb261d56a09c9faf9bff9dfb3536 (diff) | |
| download | src-af9ce4e9bb7d717279e02d46455e85ef6fb828f7.tar.gz src-af9ce4e9bb7d717279e02d46455e85ef6fb828f7.zip | |
kern_ntptime: Fix undefined behavior of the shift operator
L_LINT macro is used with negative numbers [i.e.
L_LINT(time_freq, -MAXFREQ)], it could cause undefined
behavior. It should be similar to the L_RSHIFT(v, n) macro.
MFC after: 2 weeks
Reviewed by: cy
Pull Request: https://github.com/freebsd/freebsd-src/pull/769
Signed-off-by: Dmitriy Alexandrov <d06alexandrov@gmail.com>
| -rw-r--r-- | sys/kern/kern_ntptime.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/sys/kern/kern_ntptime.c b/sys/kern/kern_ntptime.c index 815a26182096..f4071219c951 100644 --- a/sys/kern/kern_ntptime.c +++ b/sys/kern/kern_ntptime.c @@ -73,7 +73,13 @@ typedef int64_t l_fp; #define L_MPY(v, a) ((v) *= (a)) #define L_CLR(v) ((v) = 0) #define L_ISNEG(v) ((v) < 0) -#define L_LINT(v, a) ((v) = (int64_t)(a) << 32) +#define L_LINT(v, a) \ + do { \ + if ((a) < 0) \ + ((v) = -((int64_t)(-(a)) << 32)); \ + else \ + ((v) = (int64_t)(a) << 32); \ + } while (0) #define L_GINT(v) ((v) < 0 ? -(-(v) >> 32) : (v) >> 32) /* |