Messages in this thread | | | Date | Fri, 29 Aug 2008 16:28:24 +0200 | From | Haavard Skinnemoen <> | Subject | MTD/block regression (was Re: Slub debugging NAND error in 2.6.25.10.atmel.2) |
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Haavard Skinnemoen <haavard.skinnemoen@atmel.com> wrote: > Hmm...I just saw this when booting 2.6.27-rc5 on the NGW100: > > physmap platform flash device: 00800000 at 00000000 > physmap-flash.0: Found 1 x16 devices at 0x0 in 16-bit bank > Amd/Fujitsu Extended Query Table at 0x0041 > number of CFI chips: 1 > cfi_cmdset_0002: Disabling erase-suspend-program due to code brokenness. > RedBoot partition parsing not available > Using physmap partition information > Creating 3 MTD partitions on "physmap-flash.0": > 0x00000000-0x00020000 : "u-boot" > 0x00020000-0x007f0000 : "root" > kobject (91ce8410): tried to init an initialized object, something is seriously wrong. > Call trace: > [<90017184>] dump_stack+0x18/0x20 > [<900c1894>] kobject_init+0x28/0x5c > [<900c1bf6>] kobject_init_and_add+0xe/0x24 > [<900beff0>] blk_register_filter+0x28/0x40 > [<900be224>] add_disk+0x38/0x68 > [<900e70f0>] add_mtd_blktrans_dev+0x174/0x184 > [<900e748e>] mtdblock_add_mtd+0x36/0x3c > [<900e6e38>] blktrans_notify_add+0x1a/0x3a > [<900e533c>] add_mtd_device+0x60/0xa0 > [<900e5f7e>] add_mtd_partitions+0x37a/0x3a0 > [<900ec4d0>] physmap_flash_probe+0x1ec/0x21c > [<900e0f24>] platform_drv_probe+0x10/0x12 > [<900e06d0>] driver_probe_device+0x84/0xf0 > [<900e076a>] __driver_attach+0x2e/0x44 > [<900e0096>] bus_for_each_dev+0x2e/0x4c > [<900e05b6>] driver_attach+0x12/0x14 > [<900e036c>] bus_add_driver+0x6c/0x178 > [<900e08a4>] driver_register+0x58/0xb0 > [<900e1126>] platform_driver_register+0x56/0x5c > [<9000aaf6>] physmap_init+0xa/0x10 > [<9001422a>] do_one_initcall+0x2a/0x10c > [<900005b8>] kernel_init+0x48/0x90 > [<9001fcc0>] do_exit+0x0/0x4cc > > 0x007f0000-0x00800000 : "env" > kobject (91ce8410): tried to init an initialized object, something is seriously wrong. > Call trace: > [<90017184>] dump_stack+0x18/0x20 > [<900c1894>] kobject_init+0x28/0x5c > [<900c1bf6>] kobject_init_and_add+0xe/0x24 > [<900beff0>] blk_register_filter+0x28/0x40 > [<900be224>] add_disk+0x38/0x68 > [<900e70f0>] add_mtd_blktrans_dev+0x174/0x184 > [<900e748e>] mtdblock_add_mtd+0x36/0x3c > [<900e6e38>] blktrans_notify_add+0x1a/0x3a > [<900e533c>] add_mtd_device+0x60/0xa0 > [<900e5f7e>] add_mtd_partitions+0x37a/0x3a0 > [<900ec4d0>] physmap_flash_probe+0x1ec/0x21c > [<900e0f24>] platform_drv_probe+0x10/0x12 > [<900e06d0>] driver_probe_device+0x84/0xf0 > [<900e076a>] __driver_attach+0x2e/0x44 > [<900e0096>] bus_for_each_dev+0x2e/0x4c > [<900e05b6>] driver_attach+0x12/0x14 > [<900e036c>] bus_add_driver+0x6c/0x178 > [<900e08a4>] driver_register+0x58/0xb0 > [<900e1126>] platform_driver_register+0x56/0x5c > [<9000aaf6>] physmap_init+0xa/0x10 > [<9001422a>] do_one_initcall+0x2a/0x10c > [<900005b8>] kernel_init+0x48/0x90 > [<9001fcc0>] do_exit+0x0/0x4cc > > I wonder if it's related?
Ok, it turns out it's not related. It's a newly introduced regression which I've bisected down to:
commit abf5439370491dd6fbb4fe1a7939680d2a9bc9d4 Author: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Date: Sat Aug 16 14:10:05 2008 +0900
block: move cmdfilter from gendisk to request_queue
cmd_filter works only for the block layer SG_IO with SCSI block devices. It breaks scsi/sg.c, bsg, and the block layer SG_IO with SCSI character devices (such as st). We hit a kernel crash with them.
The problem is that cmd_filter code accesses to gendisk (having struct blk_scsi_cmd_filter) via inode->i_bdev->bd_disk. It works for only SCSI block device files. With character device files, inode->i_bdev leads you to struct cdev. inode->i_bdev->bd_disk->blk_scsi_cmd_filter isn't safe.
SCSI ULDs don't expose gendisk; they keep it private. bsg needs to be independent on any protocols. We shouldn't change ULDs to expose their gendisk.
This patch moves struct blk_scsi_cmd_filter from gendisk to request_queue, a common object, which eveyone can access to.
The user interface doesn't change; users can change the filters via /sys/block/. gendisk has a pointer to request_queue so the cmd_filter code accesses to struct blk_scsi_cmd_filter.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Unfortunately, I can't revert it cleanly, so it could be a false positive. But it does sort of make sense, since it makes the filter per-queue instead of per-gendisk, so if MTD uses the same queue for several block devices, the filter kobject might end up being initialized multiple times. Or something.
Haavard
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