panic[cpu0]/thread=fffffe0bf4170c20: assertion failed: strbuf <= (char *)kbuf + kbufsize + 1, file: ../../common/io/kstat.c, line: 342

[ikozhukhov]

commit a448a25 introduce panic on DilOS (commit on DilOS tree: https://bitbucket.org/dilos/dilos-illumos/commits/f0076d31d83eec58cbf52997843232cc646bc385)

panic[cpu0]/thread=fffffe0bf4170c20:
assertion failed: strbuf <= (char *)kbuf + kbufsize + 1, file: ../../common/io/kstat.c, line: 342


fffffe0011242530 genunix:process_type+194d7d ()
fffffe0011242c80 kstat:read_kstat_data+8be ()
fffffe0011242cc0 kstat:kstat_ioctl+5b ()
fffffe0011242d00 genunix:cdev_ioctl+25 ()
fffffe0011242d50 specfs:spec_ioctl+4d ()
fffffe0011242de0 genunix:fop_ioctl+55 ()
fffffe0011242ef0 genunix:ioctl+a4 ()
fffffe0011242f00 unix:brand_sys_syscall+320 ()

System information

Type	Version/Name
Distribution Name	DilOS
Distribution Version
Linux Kernel
Architecture
ZFS Version
SPL Version

Describe the problem you're observing

Describe how to reproduce the problem

ZTS

Include any warning/errors/backtraces from the system logs

proposed fix (tested on DilOS: https://bitbucket.org/dilos/dilos-illumos/commits/217477b0a87c8f778f75bb3ed6f589f696251d13):

igor@z172:~/users/igor/dilos-illumos.zfs$ g show 217477b0a87c8f778f75bb3ed6f589f696251d13
commit 217477b0a87c8f778f75bb3ed6f589f696251d13
Author: Igor Kozhukhov <[email protected]>
Date:   Wed Aug 7 19:49:55 2019 +0300

    update dataset_kstats.c

diff --git a/usr/src/uts/common/fs/zfs/dataset_kstats.c b/usr/src/uts/common/fs/zfs/dataset_kstats.c
index b1f2050df8..239f17df0d 100644
--- a/usr/src/uts/common/fs/zfs/dataset_kstats.c
+++ b/usr/src/uts/common/fs/zfs/dataset_kstats.c
@@ -149,6 +149,7 @@ dataset_kstats_create(dataset_kstats_t *dk, objset_t *objset)
        kstat->ks_data = dk_kstats;
        kstat->ks_update = dataset_kstats_update;
        kstat->ks_private = dk;
+       kstat->ks_data_size += ZFS_MAX_DATASET_NAME_LEN;

        kstat_install(kstat);
        dk->dk_kstats = kstat;

[ikozhukhov]

@behlendorf @ahrens

[behlendorf]

@ikozhukhov the proposed fix looks reasonable to me. Would you mind opening a PR for it.