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rcu: Eliminate BUG_ON() for sync.c 

The sync.c file has a number of calls to BUG_ON(), which panics the
kernel, which is not a good strategy for devices (like embedded) that
don't have a way to capture console output.  This commit therefore
changes these BUG_ON() calls to WARN_ON_ONCE(), but does so quite naively.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
hifive-unleashed-5.1
Paul E. McKenney 2018-10-22 07:43:22 -07:00
parent 651022382c
commit 042d4c70a2
1 changed files with 6 additions and 7 deletions
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13
kernel/rcu/sync.c
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@ -125,8 +125,7 @@ void rcu_sync_enter(struct rcu_sync *rsp)
rsp->gp_state = GP_PENDING;
spin_unlock_irq(&rsp->rss_lock);
BUG_ON(need_wait && need_sync);
WARN_ON_ONCE(need_wait && need_sync);
if (need_sync) {
gp_ops[rsp->gp_type].sync();
rsp->gp_state = GP_PASSED;
@ -139,7 +138,7 @@ void rcu_sync_enter(struct rcu_sync *rsp)
* Nobody has yet been allowed the 'fast' path and thus we can
* avoid doing any sync(). The callback will get 'dropped'.
*/
BUG_ON(rsp->gp_state != GP_PASSED);
WARN_ON_ONCE(rsp->gp_state != GP_PASSED);
}
}
@ -166,8 +165,8 @@ static void rcu_sync_func(struct rcu_head *rhp)
struct rcu_sync *rsp = container_of(rhp, struct rcu_sync, cb_head);
unsigned long flags;
BUG_ON(rsp->gp_state != GP_PASSED);
BUG_ON(rsp->cb_state == CB_IDLE);
WARN_ON_ONCE(rsp->gp_state != GP_PASSED);
WARN_ON_ONCE(rsp->cb_state == CB_IDLE);
spin_lock_irqsave(&rsp->rss_lock, flags);
if (rsp->gp_count) {
@ -225,7 +224,7 @@ void rcu_sync_dtor(struct rcu_sync *rsp)
{
int cb_state;
BUG_ON(rsp->gp_count);
WARN_ON_ONCE(rsp->gp_count);
spin_lock_irq(&rsp->rss_lock);
if (rsp->cb_state == CB_REPLAY)
@ -235,6 +234,6 @@ void rcu_sync_dtor(struct rcu_sync *rsp)
if (cb_state != CB_IDLE) {
gp_ops[rsp->gp_type].wait();
BUG_ON(rsp->cb_state != CB_IDLE);
WARN_ON_ONCE(rsp->cb_state != CB_IDLE);
}
}