Il 26/05/23 09:35, Chen-Yu Tsai ha scritto:
In commit 95433f726301 ("srcu: Begin offloading srcu_struct fields to
srcu_update"), a new struct srcu_usage field was added, but was not
properly initialized. This led to a "spinlock bad magic" BUG when
the SRCU notifier was ever used. This was observed in the MediaTek
CCI devfreq driver on next-20230525. Trimmed stack trace as follows:
BUG: spinlock bad magic on CPU#4, swapper/0/1
lock: 0xffffff80ff529ac0, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
Call trace:
spin_bug+0xa4/0xe8
do_raw_spin_lock+0xec/0x120
_raw_spin_lock_irqsave+0x78/0xb8
synchronize_srcu+0x3c/0x168
srcu_notifier_chain_unregister+0x5c/0xa0
cpufreq_unregister_notifier+0x94/0xe0
devfreq_passive_event_handler+0x7c/0x3e0
devfreq_remove_device+0x48/0xe8
Add __SRCU_USAGE_INIT() to SRCU_NOTIFIER_INIT() so that srcu_usage gets
initialized properly.
Fixes: 95433f726301 ("srcu: Begin offloading srcu_struct fields to srcu_update")
Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
