On 5/27/24 5:22 PM, Sebastian Andrzej Siewior wrote: > On 2024-04-20 16:25:05 [-0700], Shakeel Butt wrote: >> mod_memcg_lruvec_state() is never called from outside of memcontrol.c >> and with always irq disabled. So, replace it with the irq disabled >> version and add an assert that irq is disabled in the caller. > > unless PREEMPT_RT is enabled. In that case IRQs are not disabled as part > of local_lock_irqsave(&memcg_stock.stock_lock, …) leading to: But then the "interrupts are handled by a kernel thread that can sleep" part of RT also means it's ok to just have the stock_lock taken with no interrupts disabled as no actual raw interrupt handler will interrupt the holder and deadlock, right? > | ------------[ cut here ]------------ > | WARNING: CPU: 0 PID: 1 at mm/memcontrol.c:3150 __mod_objcg_mlstate+0xc2/0x110 > | CPU: 0 PID: 1 Comm: systemd Not tainted 6.10.0-rc1-rt0+ #17 > | Call Trace: > | <TASK> > | mod_objcg_state+0x2b3/0x320 > | __memcg_slab_post_alloc_hook+0x13c/0x340 > | kmem_cache_alloc_lru_noprof+0x2bd/0x2e0 > | alloc_inode+0x59/0xc0 > | iget_locked+0xf0/0x290 > > suggestions? So in that case the appropriate thing would be to replace the assert with lockdep_assert_held(&memcg_stock.stock_lock); ? It seems all the code paths leading here have that one. > Sebastian >
