Messages in this thread Patch in this message | | | Date | Thu, 13 Mar 2008 01:13:56 -0600 | From | "Gordon Farquharson" <> | Subject | [PATCH] mtd: prevent physmap from causing "request_module: runaway loop modprobe net-pf-1" |
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On Wed, Mar 12, 2008 at 1:19 AM, Andrew Morton <akpm@linux-foundation.org> wrote:
> Just send the patch, please. Please retain you original analysis in its > covering description.
On machines that register a physmap flash platform device (e.g. many arm machines), parse_mtd_partitions() in drivers/mtd/mtdpart.c can cause the following output in the boot log:
request_module: runaway loop modprobe net-pf-1 modprobe: FATAL: Could not load /lib/modules/2.6.25-rc4-iop32x/modules.dep: No such file or directory
modprobe: FATAL: Could not load /lib/modules/2.6.25-rc4-iop32x/modules.dep: No such file or directory
modprobe: FATAL: Could not load /lib/modules/2.6.25-rc4-iop32x/modules.dep: No such file or directory ...
To illustrate how this can occur, I'll use the example where CONFIG_KMOD=y, CONFIG_MTD_PARTITIONS=y, CONFIG_MTD_REDBOOT_PARTS=y, and CONFIG_CMDLINE_PARTS is not set. I'll also refer to the following code segment which is in drivers/mtd/mtdpart.c:parse_mtd_partitions():
for ( ; ret <= 0 && *types; types++) { parser = get_partition_parser(*types); #ifdef CONFIG_KMOD if (!parser && !request_module("%s", *types)) parser = get_partition_parser(*types); #endif if (!parser) { printk(KERN_NOTICE "%s partition parsing not available\n", *types); continue; } ret = (*parser->parse_fn)(master, pparts, origin); if (ret > 0) { printk(KERN_NOTICE "%d %s partitions found on MTD device %s\n", ret, parser->name, master->name); } put_partition_parser(parser);
I should note that I am assuming (because I don't understand how) that request_module() requires net-pf-1 to succeed. This assumption is based on my observation of the request_module message ("request_module: runaway loop modprobe net-pf-1"), and that af_unix_init() (net-pf-1 initialization) is called only after the call to request_module() in this example.
Based on the configuration and assumptions described above, the sequence of events that cause the boot log messages above are:
1. the first call to get_partition_parser() in parse_mtd_partitions() does not find the parser in the the list of registered parsers, i.e. get_partition_parser() returns a NULL pointer. In this example, the only registered parser in the list is called Redboot;
2. parse_mtd_partitions() calls request_module() with (in this example) the parameter "cmdlinepart";
3. request_module() complains (request_module: runaway loop modprobe net-pf-1, etc.) because af_unix_init() has not been called. The boot log shows that af_unix_init() is called only after parse_mtd_partitions() finishes.
register_mtd_parser: RedBoot physmap platform flash device: 00080000 at f0000000 Found: ST M29W400DB physmap-flash.0: Found 1 x16 devices at 0x0 in 16-bit bank number of JEDEC chips: 1 cfi_cmdset_0002: Disabling erase-suspend-program due to code brokenness. parse_mtd_partitions: get_partition_parser: name=cmdlinepart get_partition_parser: p->name=RedBoot get_partition_parser: p->owner=00000000 get_partition_parser: ret=00000000 parse_mtd_partitions: cmdlinepart request_module: runaway loop modprobe net-pf-1 modprobe: FATAL: Could not load /lib/modules/2.6.25-rc4-iop32x/modules.dep: No such file or directory
modprobe: FATAL: Could not load /lib/modules/2.6.25-rc4-iop32x/modules.dep: No such file or directory
modprobe: FATAL: Could not load /lib/modules/2.6.25-rc4-iop32x/modules.dep: No such file or directory
<--- 47 repeated modprobe messages deleted ---> parse_mtd_partitions: request_module called cmdlinepart partition parsing not available get_partition_parser: name=RedBoot get_partition_parser: p->name=RedBoot get_partition_parser: p->owner=00000000 get_partition_parser: ret->name=RedBoot get_partition_parser: ret=c02b0f8c parse_mtd_partitions: RedBoot parse_mtd_partitions: request_module called Searching for RedBoot partition table in physmap-flash.0 at offset 0x70000 No RedBoot partition table detected in physmap-flash.0 parse_mtd_partitions: end of function mice: PS/2 mouse device common for all mice i2c /dev entries driver rtc-rs5c372 0-0032: rs5c372a found, 24hr, driver version 0.5 rtc-rs5c372 0-0032: rtc core: registered rtc-rs5c372 as rtc0 iop-adma iop-adma.0: Intel(R) IOP: ( cpy intr ) iop-adma iop-adma.1: Intel(R) IOP: ( cpy intr ) NET: Registered protocol family 26 TCP bic registered af_unix_init: NET: Registered protocol family 1 NET: Registered protocol family 17 XScale DSP coprocessor detected. registered taskstats version 1 rtc-rs5c372 0-0032: setting system clock to 2008-03-11 03:16:46 UTC (1205205406)
The reason parse_mtd_partitions() tries to use cmdlinepart, even though it is not a registered parsing scheme when CONFIG_CMDLINE_PARTS is not set, is because cmdlinepart is hard coded in drivers/mtd/maps/physmap.c:
#ifdef CONFIG_MTD_PARTITIONS static const char *part_probe_types[] = { "cmdlinepart", "RedBoot", NULL }; #endif
The patch below changes CONFIG_MTD_REDBOOT_PARTS, CONFIG_MTD_AFS_PARTS, and CONFIG_MTD_OF_PARTS from tristate to bool, and removes the call to request_module() in drivers/mtd/mtdpart.c:parse_mtd_partitions(). The changes to the definitions of the configuration variables ensure that MTD parsers compiled into the kernel are registered before parse_mtd_partitions() is called, which negates the need to have parse_mtd_partitions() call request_module(), and thereby eliminating the call to request_module() before af_unix_init(). The patch also changes the setting of CONFIG_MTD_REDBOOT_PARTS in arch/mips/configs/mtx1_defconfig from 'm' to 'y'. This defconfig is the only one that set any of the partitioning schemes to be compiled as a module.
Signed-off-by: Gordon Farquharson <gordonfarquharson@gmail.com>
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diff --git a/arch/mips/configs/mtx1_defconfig b/arch/mips/configs/mtx1_defconfig index fa3aa39..ace51d3 100644 --- a/arch/mips/configs/mtx1_defconfig +++ b/arch/mips/configs/mtx1_defconfig @@ -743,7 +743,7 @@ CONFIG_MTD=m # CONFIG_MTD_DEBUG is not set CONFIG_MTD_CONCAT=m CONFIG_MTD_PARTITIONS=y -CONFIG_MTD_REDBOOT_PARTS=m +CONFIG_MTD_REDBOOT_PARTS=y CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK=-1 # CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED is not set # CONFIG_MTD_REDBOOT_PARTS_READONLY is not set diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig index e850334..20b4574 100644 --- a/drivers/mtd/Kconfig +++ b/drivers/mtd/Kconfig @@ -48,7 +48,7 @@ config MTD_PARTITIONS 'normal' form of partitioning used on a block device.
config MTD_REDBOOT_PARTS - tristate "RedBoot partition table parsing" + bool "RedBoot partition table parsing" depends on MTD_PARTITIONS ---help--- RedBoot is a ROM monitor and bootloader which deals with multiple @@ -135,7 +135,7 @@ config MTD_CMDLINE_PARTS If unsure, say 'N'.
config MTD_AFS_PARTS - tristate "ARM Firmware Suite partition parsing" + bool "ARM Firmware Suite partition parsing" depends on ARM && MTD_PARTITIONS ---help--- The ARM Firmware Suite allows the user to divide flash devices into @@ -151,7 +151,7 @@ config MTD_AFS_PARTS 'armflash' map driver (CONFIG_MTD_ARMFLASH) does this, for example.
config MTD_OF_PARTS - tristate "Flash partition map based on OF description" + bool "Flash partition map based on OF description" depends on PPC_OF && MTD_PARTITIONS help This provides a partition parsing function which derives diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c index c66902d..a3b3331 100644 --- a/drivers/mtd/mtdpart.c +++ b/drivers/mtd/mtdpart.c @@ -555,10 +555,6 @@ int parse_mtd_partitions(struct mtd_info *master, const char **types,
for ( ; ret <= 0 && *types; types++) { parser = get_partition_parser(*types); -#ifdef CONFIG_KMOD - if (!parser && !request_module("%s", *types)) - parser = get_partition_parser(*types); -#endif if (!parser) { printk(KERN_NOTICE "%s partition parsing not available\n", *types); -- Gordon Farquharson GnuPG Key ID: 32D6D676
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