Help - 2.4.5 SMP doesn't boot (any more)

Hi,

Yesterday I had 2.4.5 running fine. Since today, I can't boot the 2.4.5 SMP kernel any more. I get a kernel panic (invalid page request at 0000000000000010) after SMP is enabled (actually the last message I see is "trying to unmount old root ...", but from kdb messages and the fact that uniprocessor 2.4.5 boots, it is clear that it is a SMP error). The panic happens before syslog startup, so I can't send a backtrace right now (I do not have a serial console ready). kdb backtace leaves me in the start_ap function.

My BIOS has reported "8140 Processor in socket M0 failed FRB level 3 timer" for some time, but that didn't cause problems before and still doesn't with 2.4.4.

Any ideas?
Thanks,
Martin

Martin Wilck     <[email protected]>
FSC EP PS DS1, Paderborn      Tel. +49 5251 8 15113

That sounds like a known bug in 2.4.5 with undefined data in an inode during root switch. Fixed in 2.4.6-pre2. The symptoms can be weird, other people have blamed it on compilers, it is just luck if the undefined field causes a problem or not.

Index: 5.1/fs/block_dev.c

@@ -595,14 +595,15 @@ int check_disk_change(kdev_t dev)
 
 int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)
 {
-	kdev_t rdev = to_kdev_t(bdev->bd_dev);
 	struct inode inode_fake;
 	int res;
 	mm_segment_t old_fs = get_fs();
 
 	if (!bdev->bd_op->ioctl)
 		return -EINVAL;
-	inode_fake.i_rdev=rdev;
+	memset(&inode_fake, 0, sizeof(inode_fake));
+	inode_fake.i_rdev = to_kdev_t(bdev->bd_dev);
+	inode_fake.i_bdev = bdev;
 	init_waitqueue_head(&inode_fake.i_wait);
 	set_fs(KERNEL_DS);
 	res = bdev->bd_op->ioctl(&inode_fake, NULL, cmd, arg);

Yes, that was it. Thanks!!!
Martin

Martin Wilck     <[email protected]>
FSC EP PS DS1, Paderborn      Tel. +49 5251 8 15113