f9e109a209
Since commit 46b5889cc2c5("mtd: implement proper partition handling")
applied, mtd partition device won't hold some callback functions, such
as _block_isbad, _block_markbad, etc. Besides, function mtd_block_isbad()
will get mtd device's master mtd device, then invokes master mtd device's
callback function. So, following process may result mtd_block_isbad()
always return 0, even though mtd device has bad blocks:
1. Split a mtd device into 3 partitions: PA, PB, PC
[ Each mtd partition device won't has callback function _block_isbad(). ]
2. Concatenate PA and PB as a new mtd device PN
[ mtd_concat_create() finds out each subdev has no callback function
_block_isbad(), so PN won't be assigned callback function
concat_block_isbad(). ]
Then, mtd_block_isbad() checks "!master->_block_isbad" is true, will
always return 0.
Reproducer:
// reproduce.c
static int __init init_diy_module(void)
{
struct mtd_info *mtd[2];
struct mtd_info *mtd_combine = NULL;
mtd[0] = get_mtd_device_nm("NAND simulator partition 0");
if (!mtd[0]) {
pr_err("cannot find mtd1\n");
return -EINVAL;
}
mtd[1] = get_mtd_device_nm("NAND simulator partition 1");
if (!mtd[1]) {
pr_err("cannot find mtd2\n");
return -EINVAL;
}
put_mtd_device(mtd[0]);
put_mtd_device(mtd[1]);
mtd_combine = mtd_concat_create(mtd, 2, "Combine mtd");
if (mtd_combine == NULL) {
pr_err("combine failed\n");
return -EINVAL;
}
mtd_device_register(mtd_combine, NULL, 0);
pr_info("Combine success\n");
return 0;
}
1. ID="0x20,0xac,0x00,0x15"
2. modprobe nandsim id_bytes=$ID parts=50,100 badblocks=100
3. insmod reproduce.ko
4. flash_erase /dev/mtd3 0 0
libmtd: error!: MEMERASE64 ioctl failed for eraseblock 100 (mtd3)
error 5 (Input/output error)
// Should be "flash_erase: Skipping bad block at 00c80000"
Fixes:
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|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.