[BUG] kernel: kcov: a possible sleep-in-atomic-context bug in kcov_ioctl()

[Jia-Ju Bai]

The kernel may sleep with holding a spinlock.
The function call path (from bottom to top) in Linux-4.16.7 is:

[FUNC] vfree --> can sleep
kernel/kcov.c, 237: vfree in kcov_put
kernel/kcov.c, 396: kcov_put in kcov_ioctl_locked
kernel/kcov.c, 410: kcov_ioctl_locked in kcov_ioctl
kernel/kcov.c, 409: spin_lock in kcov_ioctl

This bug is found by my static analysis tool (DSAC-2) and checked by my
code review.

I do not know how to correctly fix this bug, so I just report them.


Best wishes,
Jia-Ju Bai