mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git
synced 2026-10-31 22:34:33 +01:00
Ilya Dryomov
9a5bc726d5
The following
if (val < 0)
*lvalp = (unsigned long)-val;
is incorrect because the compiler is free to assume -val to be positive
and use a sign-extend instruction for extending the bit pattern. This is
a problem if val == INT_MIN:
# echo -2147483648 >/proc/sys/dev/scsi/logging_level
# cat /proc/sys/dev/scsi/logging_level
-18446744071562067968
Cast to unsigned long before negation - that way we first sign-extend and
then negate an unsigned, which is well defined. With this:
# cat /proc/sys/dev/scsi/logging_level
-2147483648
Signed-off-by: Ilya Dryomov <[email protected]>
Cc: Mikulas Patocka <[email protected]>
Cc: Robert Xiao <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Kees Cook <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>