Commit f0c00257 authored by Peter Williams's avatar Peter Williams Committed by Linus Torvalds

[PATCH] lib: Fix bug in int_sqrt() for 64 bit longs

The implementation of int_sqrt() assumes that longs have 32 bits.  On
systems that have 64 bit longs this will result in gross errors when the
argument to the function is greater than 2^32 - 1 on such systems.  I doubt
whether any such use is currently made of int_sqrt() but the attached patch
fixes the problem anyway.
Signed-off-by: default avatarPeter Williams <>
Cc: Dave Jones <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 6bf8d889
......@@ -15,7 +15,7 @@ unsigned long int_sqrt(unsigned long x)
op = x;
res = 0;
one = 1 << 30;
one = 1UL << (BITS_PER_LONG - 2);
while (one > op)
one >>= 2;
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