From 73f88592dd1bef38542024ef8223599afc2c41bb Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Fri, 21 Jun 2024 16:38:44 -0400
Subject: [PATCH] bcachefs: mean_and_variance: Avoid too-large shift amounts
Shifting a value by the width of its type or more is undefined.
Signed-off-by: Tavian Barnes <tavianator@tavianator.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
fs/bcachefs/mean_and_variance.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/bcachefs/mean_and_variance.h b/fs/bcachefs/mean_and_variance.h
index 4fcf062dd22c7..47e4a3c3d26e7 100644
--- a/fs/bcachefs/mean_and_variance.h
+++ b/fs/bcachefs/mean_and_variance.h
@@ -111,11 +111,11 @@ static inline u128_u u128_shl(u128_u i, s8 shift)
{
u128_u r;
- r.lo = i.lo << shift;
+ r.lo = i.lo << (shift & 63);
if (shift < 64)
- r.hi = (i.hi << shift) | (i.lo >> (64 - shift));
+ r.hi = (i.hi << (shift & 63)) | (i.lo >> (-shift & 63));
else {
- r.hi = i.lo << (shift - 64);
+ r.hi = i.lo << (-shift & 63);
r.lo = 0;
}
return r;
--
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