Re: port-i386/47606: panic with ffs+wapbl on cgd on USB disk (ahci)

[Alan Barrett <apb%cequrux.com@localhost>]

The following reply was made to PR port-i386/47606; it has been noted by GNATS.

From: Alan Barrett <apb%cequrux.com@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: port-i386/47606: panic with ffs+wapbl on cgd on USB disk (ahci)
Date: Sat, 2 Mar 2013 11:28:02 +0200

 On Sat, 02 Mar 2013, apb%cequrux.com@localhost wrote:
 >db{0}> bt
 >breakpoint ...
 >vpanic ...
 >kern_assert ...
 >callout_halt ...
 >sleepq_block ...
 >ahci_channel_start ...
 >ahci_do_reset_drive ...
 >ahci_reset_drive ...
 >wddone ...
 >ahci_bio_complete ...
 >ahci_intr_port ...
 >ahci_intr ...
 >intr_biglock_wrapper ...
 >--- switch to interrupt stack ---
 
 So, wddone sees that there was some kind of error, and calls 
 
        (*wd->atabus->ata_reset_drive)(wd->drvp, AT_RST_NOCMD, NULL);
 
 The ata_reset_drive pointer refers to the ahci_reset_drive 
 function, which ends up calling ahci_channel_start, which sleeps, 
 and sleeping is not allowed in interrupt mode.
 
 --apb (Alan Barrett)