On LP64 systems, reading a sysctl file containing an INT_MIN (-2147483648) could incorrectly show -18446744071562067968 due to an incorrect conversion in do_proc_dointvec_conv. This patch fixes the edge case by converting to unsigned int first to avoid sign extending INT_MIN to unsigned long.
Test: root:/proc/sys/kernel# echo -2147483648 0 0 0 > printk root:/proc/sys/kernel# cat printk Without patch, produces -18446744071562067968 0 0 0. With patch, should produce -2147483648 0 0 0. Signed-off-by: Robert Xiao <b...@cs.cmu.edu> --- kernel/sysctl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 19b62b5..464df36 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1995,10 +1995,10 @@ static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp, int val = *valp; if (val < 0) { *negp = true; - *lvalp = (unsigned long)-val; + *lvalp = (unsigned int)-val; } else { *negp = false; - *lvalp = (unsigned long)val; + *lvalp = (unsigned int)val; } } return 0; -- 2.2.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/