Hi! On Wednesday 16 April 2014 09:38:44 micky_ching@xxxxxxxxxxxxxx wrote: > From: Micky Ching <micky_ching@xxxxxxxxxxxxxx> > > To avoid dead lock, we need make sure host->lock is always acquire > before pcr->lock. But in irq handler, we acquired pcr->lock in rtsx mfd > driver, and sd_isr_done_transfer() is called during pcr->lock already > acquired. Since in sd_isr_done_transfer() the only work we do is schdule > tasklet, the cmd_tasklet and data_tasklet never conflict, so it is safe > to remove spin_lock() here. > > Signed-off-by: Micky Ching <micky_ching@xxxxxxxxxxxxxx> > --- > drivers/mmc/host/rtsx_pci_sdmmc.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) This patch came from https://lkml.kernel.org/r/534DE1D7.3000308@xxxxxxxxxxxxxx ("Re: rtsx_pci_sdmmc lockdep splat"). With v3.15-rc1-49-g10ec34f, I have a hung machine when inserting a SD card. lockdep was not enabled for the kernel, I have not bisected yet. This patch on top of that kernel version does not help (tested by rmmod rtsx_pci_sdmmc and insmod the patched one). Console (as typed over from a picture, sorry for any typos): WARNING: CPU: 1 PID: 0 at kernel/locking/mutex.c:698 DEBUG_LOCKS_WARN_ON(in_interrupt()) Modules linked in: ... CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.15-rc1-custom-000049-g10ec34f #5 Hardware name: Shuttle Inc. XS36V/XS36V, BIOS 1.11 12/18/2012 Call trace: <IRQ> dump_stack warn_slowpath_common warn_slowpath_fmt __mutex_unlock_slowpath mutex_unlock sd_finish_request [rtsx_pci_sdmmc] tasklet_action __do_softirq irq_exit smp_apic_timer_interrupt apic_timer_interrupt <EOI> ? cpuidle_enter_state cpuidle_enter cpu_startup_entry start_secondary ---[end trace ...]--- (60 seconds later:) INFO: rcu_preempt detected stalls on CPUs/tasks: {} (detected by 1, t=18004 jiffies, g=3264, c=3263, q=2) INFO: Stall ended before state dump start I also managed to get this trace about 106 seconds later when switching TTY: INFO: task kworker/... blocked for more than 120 seconds Workqueue: kmmcd mm_rescan [mmc_core] Call trace: ? update_rq_clock.part80 ? internal_add_timer schedule schedule_preempt __mutex_lock_slowpath mutex_lock sdmmc_request [rtsx_pci_sdmmc] mmc_start_request [mmc_core] __mmc_start_req [mmc_core] mmc_wait_for_cmd [mmc_core] ? mmc_release_host [mmc_core] mmc_io_rw_direct_host [mmc_core] I'll try to get a lockdep kernel and text logs later, but perhaps you already know the issue? Peter > diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c > b/drivers/mmc/host/rtsx_pci_sdmmc.c index 453e1d4..40695e0 100644 > --- a/drivers/mmc/host/rtsx_pci_sdmmc.c > +++ b/drivers/mmc/host/rtsx_pci_sdmmc.c > @@ -108,12 +108,10 @@ static void sd_isr_done_transfer(struct > platform_device *pdev) { > struct realtek_pci_sdmmc *host = platform_get_drvdata(pdev); > > - spin_lock(&host->lock); > if (host->cmd) > tasklet_schedule(&host->cmd_tasklet); > - if (host->data) > + else if (host->data) > tasklet_schedule(&host->data_tasklet); > - spin_unlock(&host->lock); > } > > static void sd_request_timeout(unsigned long host_addr) _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
