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authorLuis R. Rodriguez <mcgrof@kernel.org>2018-03-09 15:51:20 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-03-09 16:40:02 -0800
commitac68b1b3b9c73e652dc7ce0585672e23c5a2dca4 (patch)
treebff6f75c172acda7f0240223c222fb3d1af58aaa /lib/test_kmod.c
parent0627be7d3c871035364923559543c9b2ff5357f2 (diff)
downloadlinux-ac68b1b3b9c73e652dc7ce0585672e23c5a2dca4.tar.bz2
lib/test_kmod.c: fix limit check on number of test devices created
As reported by Dan the parentheses is in the wrong place, and since unlikely() call returns either 0 or 1 it's never less than zero. The second issue is that signed integer overflows like "INT_MAX + 1" are undefined behavior. Since num_test_devs represents the number of devices, we want to stop prior to hitting the max, and not rely on the wrap arround at all. So just cap at num_test_devs + 1, prior to assigning a new device. Link: http://lkml.kernel.org/r/20180224030046.24238-1-mcgrof@kernel.org Fixes: d9c6a72d6fa2 ("kmod: add test driver to stress test the module loader") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/test_kmod.c')
-rw-r--r--lib/test_kmod.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/test_kmod.c b/lib/test_kmod.c
index e372b97eee13..0e5b7a61460b 100644
--- a/lib/test_kmod.c
+++ b/lib/test_kmod.c
@@ -1141,7 +1141,7 @@ static struct kmod_test_device *register_test_dev_kmod(void)
mutex_lock(&reg_dev_mutex);
/* int should suffice for number of devices, test for wrap */
- if (unlikely(num_test_devs + 1) < 0) {
+ if (num_test_devs + 1 == INT_MAX) {
pr_err("reached limit of number of test devices\n");
goto out;
}