On Wed, Mar 9, 2011 at 4:34 PM, Stefan Hajnoczi <[email protected]> wrote:
> The following kernel panic occurs when the RHEL6 installer starts on
> qemu.git/master:
>
> BUG: unable to handle kernel NULL pointer dereference at (null)
> IP: [<ffffffffa0062ceb>] floppy_ready+0xfb/0x730 [floppy]
>
> For full details see http://pastebin.com/SYE5A6LA.
>
> git-bisect revealed that the following commit causes this panic:
>
> commit 63ffb564dca94f8bda01ed6d209784104630a4d2
> Author: Blue Swirl <[email protected]>
> Date: Sat Feb 5 16:32:23 2011 +0000
>
> fdc: refactor device creation
>
> Turn fdc_init_isa into an inline function.
>
> Get floppy geometry directly from the drives.
>
> Don't expose FDCtrl.
>
> Signed-off-by: Blue Swirl <[email protected]>
>
> The CMOS value at 0x10 has changed from 0x00 to 0x40 but I have not
> located the root cause of the problem.
>
> Blue Swirl: Any thoughts on this bug?
The logic for calculating the drive state in pc.c does not match fdc.c
logic. Please try this patch.
diff --git a/hw/pc.c b/hw/pc.c
index 5966bf1..4d67d9f 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -382,7 +382,7 @@ void pc_cmos_init(ram_addr_t ram_size, ram_addr_t
above_4g_mem_size,
/* floppy type */
for (i = 0; i < 2; i++) {
fd[i] = drive_get(IF_FLOPPY, 0, i);
- if (fd[i]) {
+ if (fd[i] && bdrv_is_inserted(fd[i]->bdrv)) {
bdrv_get_floppy_geometry_hint(fd[i]->bdrv, &nb_heads, &max_track,
&last_sect, FDRIVE_DRV_NONE,
&fd_type[i]);
From a008e6fd41a31d437670eaa0ddf12352e8a4a8fb Mon Sep 17 00:00:00 2001
Message-Id: <a008e6fd41a31d437670eaa0ddf12352e8a4a8fb.1299926967.git.blauwir...@gmail.com>
From: Blue Swirl <[email protected]>
Date: Sat, 12 Mar 2011 09:52:25 +0000
Subject: [PATCH] pc: fix wrong CMOS values for floppy drives
Before commit 63ffb564dca94f8bda01ed6d209784104630a4d2, states for
floppy drives were calculated in fdc.c:fd_revalidate(). There it is
also considered whether a disk is inserted or not. The commit didn't copy
the logic completely to pc.c, which caused a regression.
Fix by adding the same check also to pc.c.
Signed-off-by: Blue Swirl <[email protected]>
---
hw/pc.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/hw/pc.c b/hw/pc.c
index 5966bf1..4d67d9f 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -382,7 +382,7 @@ void pc_cmos_init(ram_addr_t ram_size, ram_addr_t above_4g_mem_size,
/* floppy type */
for (i = 0; i < 2; i++) {
fd[i] = drive_get(IF_FLOPPY, 0, i);
- if (fd[i]) {
+ if (fd[i] && bdrv_is_inserted(fd[i]->bdrv)) {
bdrv_get_floppy_geometry_hint(fd[i]->bdrv, &nb_heads, &max_track,
&last_sect, FDRIVE_DRV_NONE,
&fd_type[i]);
--
1.7.2.3
