commit 5a3c6b9688306c466f80672761b5009da6b9dfb7 Author: Arnaldo Carvalho de Melo Date: Wed Sep 6 10:30:08 2017 -0300 infiniband: Convert per-NUMA send_context->alloc_lock to a raw spinlock sc_buffer_alloc() disables preemption that will be reenabled by either pio_copy() or seg_pio_copy_end(). But before disabling preemption it grabs a spin lock that will be dropped after it disables preemption, which ends up triggering a warning in migrate_disable() later on. spin_lock_irqsave(&sc->alloc_lock) migrate_disable() ++p->migrate_disable -> 2 preempt_disable() spin_unlock_irqrestore(&sc->alloc_lock) migrate_enable() in_atomic(), so just returns, migrate_disable stays at 2 spin_lock_irqsave(some other lock) -> b00m And the WARN_ON code ends up tripping over this over and over in log_store(). Sequence captured via ftrace_dump_on_oops + crash utility 'dmesg' command. [512258.613862] sm-3297 16 .....11 359465349134644: sc_buffer_alloc <-hfi1_verbs_send_pio [512258.613876] sm-3297 16 .....11 359465349134719: migrate_disable <-sc_buffer_alloc [512258.613890] sm-3297 16 .....12 359465349134798: rt_spin_lock <-sc_buffer_alloc [512258.613903] sm-3297 16 ....112 359465349135481: rt_spin_unlock <-sc_buffer_alloc [512258.613916] sm-3297 16 ....112 359465349135556: migrate_enable <-sc_buffer_alloc [512258.613935] sm-3297 16 ....112 359465349135788: seg_pio_copy_start <-hfi1_verbs_send_pio [512258.613954] sm-3297 16 ....112 359465349136273: update_sge <-hfi1_verbs_send_pio [512258.613981] sm-3297 16 ....112 359465349136373: seg_pio_copy_mid <-hfi1_verbs_send_pio [512258.613999] sm-3297 16 ....112 359465349136873: update_sge <-hfi1_verbs_send_pio [512258.614017] sm-3297 16 ....112 359465349136956: seg_pio_copy_mid <-hfi1_verbs_send_pio [512258.614035] sm-3297 16 ....112 359465349137221: seg_pio_copy_end <-hfi1_verbs_send_pio [512258.614048] sm-3297 16 .....12 359465349137360: migrate_disable <-hfi1_verbs_send_pio [512258.614065] sm-3297 16 .....12 359465349137476: warn_slowpath_null <-migrate_disable [512258.614081] sm-3297 16 .....12 359465349137564: __warn <-warn_slowpath_null [512258.614088] sm-3297 16 .....12 359465349137958: printk <-__warn [512258.614096] sm-3297 16 .....12 359465349138055: vprintk_default <-printk [512258.614104] sm-3297 16 .....12 359465349138144: vprintk_emit <-vprintk_default [512258.614111] sm-3297 16 d....12 359465349138312: _raw_spin_lock <-vprintk_emit [512258.614119] sm-3297 16 d...112 359465349138789: log_store <-vprintk_emit [512258.614127] sm-3297 16 .....12 359465349139068: migrate_disable <-vprintk_emit Signed-off-by: Arnaldo Carvalho de Melo diff --git a/drivers/infiniband/hw/hfi1/pio.c b/drivers/infiniband/hw/hfi1/pio.c index 615be68..8f28f8f 100644 --- a/drivers/infiniband/hw/hfi1/pio.c +++ b/drivers/infiniband/hw/hfi1/pio.c @@ -744,7 +744,7 @@ struct send_context *sc_alloc(struct hfi1_devdata *dd, int type, sc->dd = dd; sc->node = numa; sc->type = type; - spin_lock_init(&sc->alloc_lock); + raw_spin_lock_init(&sc->alloc_lock); spin_lock_init(&sc->release_lock); spin_lock_init(&sc->credit_ctrl_lock); INIT_LIST_HEAD(&sc->piowait); @@ -929,13 +929,13 @@ void sc_disable(struct send_context *sc) return; /* do all steps, even if already disabled */ - spin_lock_irqsave(&sc->alloc_lock, flags); + raw_spin_lock_irqsave(&sc->alloc_lock, flags); reg = read_kctxt_csr(sc->dd, sc->hw_context, SC(CTRL)); reg &= ~SC(CTRL_CTXT_ENABLE_SMASK); sc->flags &= ~SCF_ENABLED; sc_wait_for_packet_egress(sc, 1); write_kctxt_csr(sc->dd, sc->hw_context, SC(CTRL), reg); - spin_unlock_irqrestore(&sc->alloc_lock, flags); + raw_spin_unlock_irqrestore(&sc->alloc_lock, flags); /* * Flush any waiters. Once the context is disabled, @@ -1232,7 +1232,7 @@ int sc_enable(struct send_context *sc) * worry about locking since the releaser will not do anything * if the context accounting values have not changed. */ - spin_lock_irqsave(&sc->alloc_lock, flags); + raw_spin_lock_irqsave(&sc->alloc_lock, flags); sc_ctrl = read_kctxt_csr(dd, sc->hw_context, SC(CTRL)); if ((sc_ctrl & SC(CTRL_CTXT_ENABLE_SMASK))) goto unlock; /* already enabled */ @@ -1303,7 +1303,7 @@ int sc_enable(struct send_context *sc) sc->flags |= SCF_ENABLED; unlock: - spin_unlock_irqrestore(&sc->alloc_lock, flags); + raw_spin_unlock_irqrestore(&sc->alloc_lock, flags); return ret; } @@ -1361,9 +1361,9 @@ void sc_stop(struct send_context *sc, int flag) sc->flags |= flag; /* stop buffer allocations */ - spin_lock_irqsave(&sc->alloc_lock, flags); + raw_spin_lock_irqsave(&sc->alloc_lock, flags); sc->flags &= ~SCF_ENABLED; - spin_unlock_irqrestore(&sc->alloc_lock, flags); + raw_spin_unlock_irqrestore(&sc->alloc_lock, flags); wake_up(&sc->halt_wait); } @@ -1391,9 +1391,9 @@ struct pio_buf *sc_buffer_alloc(struct send_context *sc, u32 dw_len, int trycount = 0; u32 head, next; - spin_lock_irqsave(&sc->alloc_lock, flags); + raw_spin_lock_irqsave(&sc->alloc_lock, flags); if (!(sc->flags & SCF_ENABLED)) { - spin_unlock_irqrestore(&sc->alloc_lock, flags); + raw_spin_unlock_irqrestore(&sc->alloc_lock, flags); goto done; } @@ -1402,7 +1402,7 @@ retry: if (blocks > avail) { /* not enough room */ if (unlikely(trycount)) { /* already tried to get more room */ - spin_unlock_irqrestore(&sc->alloc_lock, flags); + raw_spin_unlock_irqrestore(&sc->alloc_lock, flags); goto done; } /* copy from receiver cache line and recalculate */ @@ -1458,7 +1458,7 @@ retry: */ smp_wmb(); sc->sr_head = next; - spin_unlock_irqrestore(&sc->alloc_lock, flags); + raw_spin_unlock_irqrestore(&sc->alloc_lock, flags); /* finish filling in the buffer outside the lock */ pbuf->start = sc->base_addr + fill_wrap * PIO_BLOCK_SIZE; diff --git a/drivers/infiniband/hw/hfi1/pio.h b/drivers/infiniband/hw/hfi1/pio.h index 867e5ff..06dfc6f 100644 --- a/drivers/infiniband/hw/hfi1/pio.h +++ b/drivers/infiniband/hw/hfi1/pio.h @@ -112,7 +112,7 @@ struct send_context { u8 group; /* credit return group */ /* allocator fields */ - spinlock_t alloc_lock ____cacheline_aligned_in_smp; + raw_spinlock_t alloc_lock ____cacheline_aligned_in_smp; u32 sr_head; /* shadow ring head */ unsigned long fill; /* official alloc count */ unsigned long alloc_free; /* copy of free (less cache thrash) */