Re: [PATCH v2 1/2] rcuscale: Do a proper cleanup if kfree_scale_init() fails
From: Neeraj Upadhyay
Date: Wed Nov 13 2024 - 12:00:56 EST
On 11/13/2024 4:30 PM, Uladzislau Rezki (Sony) wrote:
> A static analyzer for C, Smatch, reports and triggers below
> warnings:
>
> kernel/rcu/rcuscale.c:1215 rcu_scale_init()
> warn: inconsistent returns 'global &fullstop_mutex'.
>
> The checker complains about, we do not unlock the "fullstop_mutex"
> mutex, in case of hitting below error path:
>
> <snip>
> ...
> if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start < 2 * HZ)) {
> pr_alert("ERROR: call_rcu() CBs are not being lazy as expected!\n");
> WARN_ON_ONCE(1);
> return -1;
> ^^^^^^^^^^
> ...
> <snip>
>
> it happens because "-1" is returned right away instead of
> doing a proper unwinding.
>
> Fix it by jumping to "unwind" label instead of returning -1.
>
> Reviewed-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Closes: https://lore.kernel.org/rcu/ZxfTrHuEGtgnOYWp@pc636/T/
> Fixes: 084e04fff160 ("rcuscale: Add laziness and kfree tests")
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
> ---
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@xxxxxxx>
- Neeraj