Re: kern/55402: amd64/9.99.68/9.99.68: xen/zfs - kernel: double fault trap, code=0

[Frank Kardel <kardel%netbsd.org@localhost>]

The following reply was made to PR kern/55402; it has been noted by GNATS.

From: Frank Kardel <kardel%netbsd.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/55402: amd64/9.99.68/9.99.68: xen/zfs - kernel: double fault
 trap, code=0
Date: Sat, 20 Jun 2020 15:40:49 +0200

 Well it goes a bit further but hits the double fault
 
 now with 57 frames (two > 1k) at about the same accumulated stack size.
 
 Some space was saved by the patch, but presumably not enough.
 
 0: vdev_queue_io_to_issue framesize 1152
 1: vdev_queue_io_remove framesize 32
 2: vdev_queue_io_to_issue framesize 1152
 3: vdev_queue_io framesize 64
 4: vdev_queue_io_done framesize 64
 5: zio_vdev_io_start framesize 96
 6: zio_execute framesize 80
 7: zio_nowait framesize 48
 8: vdev_mirror_io_start framesize 128
 9: zio_vdev_io_start framesize 96
 10: zio_execute framesize 80
 11: zio_nowait framesize 48
 12: vdev_mirror_io_start framesize 128
 13: zio_vdev_io_start framesize 96
 14: zio_execute framesize 80
 15: zio_nowait framesize 48
 16: arc_read_done framesize 80
 17: l2arc_read_done framesize 112
 18: arc_read framesize 192
 19: dbuf_read framesize 176
 20: dbuf_read_done framesize 48
 21: dmu_buf_hold_by_dnode framesize 64
 22: zap_get_leaf_byblk framesize 112
 23: zap_deref_leaf framesize 64
 24: fzap_length framesize 112
 25: zap_length_uint64 framesize 112
 26: ddt_zap_lookup framesize 368
 27: ddt_class_contains framesize 448
 28: dsl_scan_visitbp framesize 224
 29: dsl_scan_visitbp framesize 224
 30: dsl_scan_visitbp framesize 224
 31: dsl_scan_visitdnode framesize 144
 32: dsl_scan_visitbp framesize 224
 33: dsl_scan_visitbp framesize 224
 34: dsl_scan_visitbp framesize 224
 35: dsl_scan_visitbp framesize 224
 36: dsl_scan_visitbp framesize 224
 37: dsl_scan_visitbp framesize 224
 38: dsl_scan_visitdnode framesize 144
 39: dsl_scan_visitbp framesize 224
 40: dsl_scan_visitds framesize 144
 41: dsl_scan_visitdnode framesize 144
 42: dsl_scan_visitbp framesize 224
 43: dsl_scan_visitds framesize 144
 44: dsl_scan_visit framesize 560
 45: dsl_scan_sync_state framesize 32
 46: dsl_scan_sync framesize 112
 47: spa_sync_version framesize 48
 48: spa_sync_nvlist framesize 96
 49: spa_sync_config_object framesize 432
 50: spa_sync_aux_dev.part.6 framesize 112
 51: spa_sync_props framesize 128
 52: spa_sync framesize 208
 53: spa_sync_allpools framesize 32
 54: spa_sync_pass framesize 8
 55: spa_syncing_txg framesize 8
 56: txg_sync_thread framesize 240
 
 frame size sum = 10480, # frames 57
 
 On 06/20/20 15:10, Jaromír DoleÄ?ek wrote:
 > The following reply was made to PR kern/55402; it has been noted by GNATS.
 >
 > From: =?UTF-8?B?SmFyb23DrXIgRG9sZcSNZWs=?= <jaromir.dolecek%gmail.com@localhost>
 > To: "gnats-bugs%NetBSD.org@localhost" <gnats-bugs%netbsd.org@localhost>
 > Cc:
 > Subject: Re: kern/55402: amd64/9.99.68/9.99.68: xen/zfs - kernel: double fault
 >   trap, code=0
 > Date: Sat, 20 Jun 2020 15:08:39 +0200
 >
 >   In order to verify whether it's a stack issue, can you please test
 >   with the following patch?
 >   
 >   http://www.netbsd.org/~jdolecek/zfs_reduce_stack.diff
 >