On Thu, Feb 19 2009, Gao, Yunpeng wrote: > > Hi all, > > Sorry for the too long email. But I encountered a kernle OOP problem > when testing my standalone NAND block driver (it's almost a normal > block device driver) and not sure why this happen. > > In my development environment, the linux 2.6.27 kernel boot with > initrd, then 'chroot' to an MMC card. After chroot, I try to mkfs.ext3 > on NAND device. but it caused the kernel OOP message. If I mkfs.ext3 > on NAND device before chroot, then it works well (it can mount/umount, > copy file correctly accross system reboot). > > Below is the log message (/dev/mmcblk0 is the MMC card device node, > and /dev/nda is the NAND flash device node) and part of the driver > code. > > From the OOP message, It seems there's improper usage of locks in my > driver code, but actually, there only one spinlock used in the driver > (spinlock_t qlock defined in struct spectra_nand_dev). And it only > used by registered request queue. Also, I used a semaphore > ('spectra_sem') to prevent the low layer function from being > re-entered. As the low layer (hardware layer) now works in PIO mode > and it's very slowly, so maybe it holds the spinlock or semaphore for > too long time? You call the bvec_kmap_irq() and then call a function that does a down(). This is illegal, as you cannot block/schedule with interrupts disabled. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html