CVS commit: src/sys/kern

["Constantine A. Murenin" <cnst%netbsd.org@localhost>]

Module Name:    src
Committed By:   cnst
Date:           Mon Sep 30 23:23:59 UTC 2019

Modified Files:
        src/sys/kern: subr_disk.c

Log Message:
kern/subr_disk: bounds_check_with_label: really protect against div by zero

Solves kernel panic in NetBSD 8.1 amd64 on VirtualBox 6.0.12 r133076.

Triggered with an NVMe controller without any actual discs behind it:

nvme0 at pci0 dev 14 function 0: vendor 80ee product 4e56 (rev. 0x00)
nvme0: NVMe 1.2
nvme0: interrupting at ioapic0 pin 22
nvme0: ORCL-VBOX-NVME-VER12, firmware 1.0, serial VB1234-56789
ld0 at nvme0 nsid 1
ld0: 0, 0 cyl, 16 head, 63 sec, 1 bytes/sect x 0 sectors

Code path is reached 4 times during normal boot, each time after wd0a
is already mounted; this patch avoids a crash with a dirty filesystem.


To generate a diff of this commit:
cvs rdiff -u -r1.128 -r1.129 src/sys/kern/subr_disk.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.