On Thu, Mar 26, 2020 at 3:44 PM Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote:
>
> Every time kcov_start/stop() is called, t->kcov is also assigned, so
> move the assignment into the functions.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> ---
> kernel/kcov.c | 16 +++++++---------
> 1 file changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/kcov.c b/kernel/kcov.c
> index cc5900ac2467..888d0a236b04 100644
> --- a/kernel/kcov.c
> +++ b/kernel/kcov.c
> @@ -309,10 +309,12 @@ void notrace __sanitizer_cov_trace_switch(u64 val, u64 *cases)
> EXPORT_SYMBOL(__sanitizer_cov_trace_switch);
> #endif /* ifdef CONFIG_KCOV_ENABLE_COMPARISONS */
>
> -static void kcov_start(struct task_struct *t, unsigned int size,
> - void *area, enum kcov_mode mode, int sequence)
> +static void kcov_start(struct task_struct *t, struct kcov *kcov,
> + unsigned int size, void *area, enum kcov_mode mode,
> + int sequence)
> {
> kcov_debug("t = %px, size = %u, area = %px\n", t, size, area);
> + t->kcov = kcov;
> /* Cache in task struct for performance. */
> t->kcov_size = size;
> t->kcov_area = area;
> @@ -326,6 +328,7 @@ static void kcov_stop(struct task_struct *t)
> {
> WRITE_ONCE(t->kcov_mode, KCOV_MODE_DISABLED);
> barrier();
> + t->kcov = NULL;
> t->kcov_size = 0;
> t->kcov_area = NULL;
> }
> @@ -333,7 +336,6 @@ static void kcov_stop(struct task_struct *t)
> static void kcov_task_reset(struct task_struct *t)
> {
> kcov_stop(t);
> - t->kcov = NULL;
> t->kcov_sequence = 0;
> t->kcov_handle = 0;
> }
> @@ -584,9 +586,8 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
> return mode;
> kcov_fault_in_area(kcov);
> kcov->mode = mode;
> - kcov_start(t, kcov->size, kcov->area, kcov->mode,
> + kcov_start(t, kcov, kcov->size, kcov->area, kcov->mode,
> kcov->sequence);
> - t->kcov = kcov;
> kcov->t = t;
> /* Put either in kcov_task_exit() or in KCOV_DISABLE. */
> kcov_get(kcov);
> @@ -778,7 +779,6 @@ void kcov_remote_start(u64 handle)
> kcov = remote->kcov;
> /* Put in kcov_remote_stop(). */
> kcov_get(kcov);
> - t->kcov = kcov;
> /*
> * Read kcov fields before unlock to prevent races with
> * KCOV_DISABLE / kcov_remote_reset().
> @@ -792,7 +792,6 @@ void kcov_remote_start(u64 handle)
> if (!area) {
> area = vmalloc(size * sizeof(unsigned long));
> if (!area) {
> - t->kcov = NULL;
> kcov_put(kcov);
> return;
> }
> @@ -800,7 +799,7 @@ void kcov_remote_start(u64 handle)
> /* Reset coverage size. */
> *(u64 *)area = 0;
>
> - kcov_start(t, size, area, mode, sequence);
> + kcov_start(t, kcov, size, area, mode, sequence);
>
> }
> EXPORT_SYMBOL(kcov_remote_start);
> @@ -873,7 +872,6 @@ void kcov_remote_stop(void)
> return;
>
> kcov_stop(t);
> - t->kcov = NULL;
>
> spin_lock(&kcov->lock);
> /*
> --
> 2.26.0.rc2.310.g2932bb562d-goog
>
