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

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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.
This commit is contained in:
cnst 2019-09-30 23:23:59 +00:00
parent 4d18bc5819
commit da5825f8ed
1 changed files with 3 additions and 3 deletions
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6
sys/kern/subr_disk.c
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@ -1,4 +1,4 @@
/* $NetBSD: subr_disk.c,v 1.128 2019/05/22 08:47:02 hannken Exp $ */
/* $NetBSD: subr_disk.c,v 1.129 2019/09/30 23:23:59 cnst Exp $ */
/*-
* Copyright (c) 1996, 1997, 1999, 2000, 2009 The NetBSD Foundation, Inc.
@ -67,7 +67,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_disk.c,v 1.128 2019/05/22 08:47:02 hannken Exp $");
__KERNEL_RCSID(0, "$NetBSD: subr_disk.c,v 1.129 2019/09/30 23:23:59 cnst Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
@ -385,7 +385,7 @@ bounds_check_with_label(struct disk *dk, struct buf *bp, int wlabel)
}
/* Protect against division by zero. XXX: Should never happen?!?! */
if (lp->d_secpercyl == 0) {
if ((lp->d_secsize / DEV_BSIZE) == 0 || lp->d_secpercyl == 0) {
bp->b_error = EINVAL;
return -1;
}