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charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/13/22 07:55, Ondrej Zary wrote: > On Wednesday 16 November 2022 02:30:46 Damien Le Moal wrote: >> On 2022/11/15 23:56, Ondrej Zary wrote: >>> On Tuesday 15 November 2022, Damien Le Moal wrote: >>>> On 11/15/22 04:25, Ondrej Zary wrote: >>>>> On Monday 14 November 2022 09:03:28 Damien Le Moal wrote: >>>>>> On 11/14/22 16:53, Ondrej Zary wrote: >>>>>>> On Monday 14 November 2022, Damien Le Moal wrote: >>>>>>>> On 11/12/22 20:17, Ondrej Zary wrote: >>>>>>>>> On Wednesday 19 October 2022 09:34:31 Christoph Hellwig wrote: >>>>>>>>>> It's been a while - did you get a chance to make some progress on >>>>>>>>>> this? Do you need any help to unblock you? >>>>>>>>>> >>>>>>>>> >>>>>>>>> Sorry again, I'm back now. Trying to fix locking problems. >>>>>>>>> Added this to each function for analysis how the functions are called wrt. >>>>>>>>> locking: >>>>>>>>> >>>>>>>>> printk("%s, locked=%d\n", __FUNCTION__, spin_is_locked(ap->lock)); >>>>>>>> >>>>>>>> Do you have your code somewhere that we can look at ? >>>>>>> >>>>>>> This is the current version with debug printks. I've also added dump_stack() >>>>>>> to find out the code path but haven't analyzed the output yet. >>>>>> >>>>>> Can you send a proper patch ? Or a link to a git tree ? That is easier to >>>>>> handle than pasted code in an email... >>>>> >>>>> Patch against what? I don't have a git server. >>>> >>>> patch against current 6.1-rc, or against an older kernel should be OK too. >>>> But please "git send-email" a patch, or push your dev tree to github ? >>>> >>>>> I've done some call trace analysis. These code paths are calling >>>>> pata_parport functions with ap->lock locked during init. >>>>> >>>>> Comm: kworker, Workqueue: ata_sff ata_sff_pio_task >>>>> ata_sff_hsm_move -> ata_pio_sectors-> ata_sff_altstatus -> pata_parport_tf_read -> pata_parport_check_altstatus >>>>> ata_sff_hsm_move -> ata_sff_altstatus -> pata_parport_tf_read -> pata_parport_check_altstatus >>>>> ata_sff_pio_task -> ata_sff_busy_wait -> pata_parport_check_status >>>>> ata_sff_hsm_move -> ata_wait_idle -> ata_sff_busy_wait -> pata_parport_check_status >>>>> ata_sff_hsm_move -> ata_hsm_qc_complete -> ata_sff_irq_on -> ata_wait_idle -> ata_sff_busy_wait -> pata_parport_check_status >>>>> ata_sff_pio_task -> ata_sff_hsm_move -> ata_pio_sectors -> ata_pio_sector -> ata_pio_xfer -> pata_parport_data_xfer >>>>> ata_sff_pio_task -> ata_sff_hsm_move -> pata_parport_data_xfer >>>>> ata_sff_pio_task -> ata_sff_hsm_move -> pata_parport_tf_read >>>>> ata_sff_hsm_move -> ata_hsm_qc_complete -> ata_qc_complete -> fill_result_tf -> ata_sff_qc_fill_rtf -> pata_parport_tf_read >>>>> ata_sff_hsm_move -> ata_pio_sectors -> ata_sff_altstatus -> pata_parport_check_altstatus >>>>> ata_sff_hsm_move -> ata_sff_altstatus -> pata_parport_check_altstatus >>>>> >>>>> Comm: modprobe >>>>> ata_host_start -> ata_eh_freeze_port -> ata_sff_freeze -> pata_parport_check_status >>>>> >>>>> Comm: scsi_eh_4 >>>>> ata_eh_recover -> ata_eh_reset -> ata_eh_thaw_port -> ata_sff_thaw -> ata_sff_irq_on -> ata_wait_idle -> ata_sff_busy_wait -> pata_parport_check_status >>>>> ata_eh_reset -> ata_eh_freeze_port -> ata_sff_freeze -> pata_parport_check_status >>>>> ata_scsi_error -> ata_scsi_port_error_handler -> ata_port_freeze -> ata_sff_freeze -> pata_parport_check_status >>>>> ata_sff_error_handler -> pata_parport_drain_fifo -> pata_parport_check_status >>>> >>>> What exactly are the issues you are having with ap->lock ? It looks like >>>> you have done a lot of analysis of the code, but without any context about >>>> the problem, I do not understand what I am looking at. >>>> >>> >>> The problem is that pi_connect() can sleep because it calls >>> parport_claim_or_block(). And any access (even reading ATA status register) >>> requires pi_connect. >> >> OK. Let me have a look. >> > > The locking problems seem not to be easily solvable. Maybe a hack that grabs > the parport before registering ata interface (and keeps it until the > interface is disabled) will help? That will prevent multiple chained devices > on one parport from working but can get pata_parport moving. I have been very busy and had no time to look at this. Sorry about that. I will have a look before year-end break. -- Damien Le Moal Western Digital Research