On 5/1/05, Richard Purdie <[email protected]> wrote:
> I've switched back to 2.6.12-rc3-mm1 and added some debuging to all the ide
> functions to trace the order functions are getting called. I've shown the
> result below for two different oops. There is more than one problem. The
> first problem was introduced in 2.6.12-rc1-bk1 in the ide-disk changes. The
> second has been around for a while but is showing up again.
>
> The problem is idedisk_cleanup() gets called twice from ide_unregister().
> Once here:
>
> for (unit = 0; unit < MAX_DRIVES; ++unit) {
> drive = &hwif->drives[unit];
> if (!drive->present)
> continue;
> DRIVER(drive)->cleanup(drive);
> }
>
> and secondly in ide_unregister indirectly via:
>
> blk_cleanup_queue(drive->queue);
> printk(KERN_ERR "ide_unregister4()\n");
> device_unregister(&drive->gendev);
> down(&drive->gendev_rel_sem);
> spin_lock_irq(&ide_lock);
> drive->queue = NULL;
> printk(KERN_ERR "ide_unregister5()\n");
>
> device_unregister() triggers ide_drive_remove() which calls
> DRIVER(drive)->cleanup(drive);
>
> In the first call to idedisk_cleanup(), ide_disk_put(idkp) is called which
> decreases the reference counter to zero. This triggers ide_disk_release()
> which calls kfree(idkp). Hence the second call to idedisk_cleanup() calls
> what is now a null pointer (or worse).
Thanks for excellent debugging.
Both problems should be fixed by "convert IDE device drivers to
driver-model" patch but I need to resync it against latest kernels.
Bartlomiej
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
