mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2025-01-10 07:00:48 +00:00
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 <idryomov@gmail.com> Cc: Mikulas Patocka <mikulas@twibright.com> Cc: Robert Xiao <nneonneo@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>