Hello!
On May 31, 2017, at 4:00 AM, Jia-Ju Bai wrote:
> The driver may sleep under a spin lock, and the function call path is:
> cfs_wi_exit (acquire the lock by spin_lock)
> LASSERT
> lbug_with_loc
> libcfs_debug_dumplog
> schedule and kthread_run --> may sleep
>
> To fix it, all "LASSERT" is placed out of the spin_lock and spin_unlock.
>
> Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxx>
> ---
> drivers/staging/lustre/lnet/libcfs/workitem.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/staging/lustre/lnet/libcfs/workitem.c b/drivers/staging/lustre/lnet/libcfs/workitem.c
> index dbc2a9b..928d06d 100644
> --- a/drivers/staging/lustre/lnet/libcfs/workitem.c
> +++ b/drivers/staging/lustre/lnet/libcfs/workitem.c
> @@ -111,22 +111,23 @@ struct cfs_wi_sched {
> {
> LASSERT(!in_interrupt()); /* because we use plain spinlock */
> LASSERT(!sched->ws_stopping);
> + LASSERT(wi->wi_running);
> + if (wi->wi_scheduled) {
> + LASSERT(!list_empty(&wi->wi_list));
> + LASSERT(sched->ws_nscheduled > 0);
> + }
Similarly here and in all other patches about LASSERT calls under spinlocks() from you,
just think of them as a panic() call, no operations are expected to continue
after it triggers.
Thanks.
>
> spin_lock(&sched->ws_lock);
>
> - LASSERT(wi->wi_running);
> if (wi->wi_scheduled) { /* cancel pending schedules */
> - LASSERT(!list_empty(&wi->wi_list));
> list_del_init(&wi->wi_list);
> -
> - LASSERT(sched->ws_nscheduled > 0);
> sched->ws_nscheduled--;
> }
>
> - LASSERT(list_empty(&wi->wi_list));
> -
> wi->wi_scheduled = 1; /* LBUG future schedule attempts */
> spin_unlock(&sched->ws_lock);
> +
> + LASSERT(list_empty(&wi->wi_list));
> }
> EXPORT_SYMBOL(cfs_wi_exit);
>
> --
> 1.7.9.5
>
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