我正在尝试使用Buildroot构建一个在PocketBeagle上运行的嵌入式Linux;并遵循（source1）中的说明。然后将生成的图像复制到uSD卡。 将uSD卡插入Pocketbeagle并通过串行连接监控启动过程时;我收到以下错误：
No filesystem could mount root, tried:
ext4
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,1)
---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,1).
使用的资源是：
Buildroot：2018.02
文件系统：ext4
Bootloader：U-Boot（自定义版本2018.01）
内核版本：4.14.24
应用上面源中所述的所有补丁，可以在（source2）中找到：
- 0001-Stripped-back-pocketbeagle-devicetree.patch
- 0001-am335x_evm-uEnv.txt-bootz-n-fixes.patch
- 0002-U-Boot-BeagleBone-Cape-Manager.patch
- 0003-pocketbeagle-tweaks.patch
运行构建会生成以下文件和图像：
MLO：第一阶段引导程序
U-boot.img：第二阶段bootloader
uEnv.txt：U-boot环境
zImage：Linux内核映像
am335x-pocketbeagle.dtb：Linux内核设备树Blob
rootfs.ext4：根文件系统映像
uEnv.txt如下：
fdtfile=am335x-pocketbeagle.dtb
bootpart=0:1
bootdir=
bootargs=console=ttyO0,115200n8 root=/dev/mmcblk0p1 rw rootfstype=ext4 rootwait
uenvcmd=run loadimage;run loadfdt;printenv bootargs;bootz ${loadaddr} - ${fdtaddr};
然后在buildroot（和重建）中使用 genimage 生成包含两个分区的uSd图像：
1. FAT分区包含引导加载程序映像，内核映像和设备树
2.包含根文件系统ext4
生成的图像称为 sdcard.img 是使用程序etcher（etcher-electron-1.4.3-x86_64.AppImage）或（ sudo dd）复制到uSD卡的if = output / images / sdcard.img = / dev / mmcblk0 bs = 1M ）
我使用了两张不同的uSD卡来测试构建，但结果是一样的：
1.金石32 GB（SDHC 10）
2. Sandisk 16GB（SDHC 10）
值得一提的是，我使用相同的uSD卡从official site加载PocketBeagle的原始图像并从它们启动，卡片启动没有问题。
非常感谢任何提供帮助的想法。
ADDENDUM
日志文件中显示的另一个错误发生在启动开始时：
U-Boot SPL 2018.01 (Mar 24 2018 - 21:13:25)
Trying to boot from MMC1
*** Warning - bad CRC, using default environment
reading u-boot.img
reading u-boot.img
U-Boot 2018.01 (Mar 24 2018 - 21:13:25 +0100)
CPU : AM335X-GP rev 2.1 I2C: ready DRAM: 512 MiB
No match for driver 'omap_hsmmc'
No match for driver 'omap_hsmmc'
Some drivers were not found
Reset Source: Power-on reset has occurred.
MMC: OMAP SD/MMC: 0, OMAP SD/MMC: 1
*** Warning - bad CRC, using default environment
完整日志如下：
U-Boot SPL 2018.01 (Mar 24 2018 - 21:13:25)
Trying to boot from MMC1
*** Warning - bad CRC, using default environment
reading u-boot.img
reading u-boot.img
U-Boot 2018.01 (Mar 24 2018 - 21:13:25 +0100)
CPU : AM335X-GP rev 2.1
I2C: ready
DRAM: 512 MiB
No match for driver 'omap_hsmmc'
No match for driver 'omap_hsmmc'
Some drivers were not found
Reset Source: Power-on reset has occurred.
MMC: OMAP SD/MMC: 0, OMAP SD/MMC: 1
*** Warning - bad CRC, using default environment
Model: BeagleBoard.org PocketBeagle
<ethaddr> not set. Validating first E-fuse MAC
Net: No ethernet found.
Press SPACE to abort autoboot in 2 seconds
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
gpio: pin 56 (gpio 56) value is 0
gpio: pin 55 (gpio 55) value is 0
gpio: pin 54 (gpio 54) value is 0
gpio: pin 53 (gpio 53) value is 1
switch to partitions #0, OK
mmc0 is current device
gpio: pin 54 (gpio 54) value is 1
Checking for: /uEnv.txt ...
reading uEnv.txt
218 bytes read in 4 ms (52.7 KiB/s)
gpio: pin 55 (gpio 55) value is 1
Loaded environment from /uEnv.txt
Importing environment from mmc ...
Checking if uenvcmd is set ...
gpio: pin 56 (gpio 56) value is 1
Running uenvcmd ...
reading /zImage
5540120 bytes read in 351 ms (15.1 MiB/s)
loading /am335x-pocketbeagle.dtb ...
reading /am335x-pocketbeagle.dtb
33516 bytes read in 9 ms (3.6 MiB/s)
bootargs=console=ttyO0,115200n8 root=/dev/mmcblk0p1 rw rootfstype=ext4 rootwait
## Flattened Device Tree blob at 88000000
Booting using the fdt blob at 0x88000000
Loading Device Tree to 8fff4000, end 8ffff2eb ... OK
Starting kernel ...
[ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Linux version 4.14.24 (ammar@ammar-System-Product-Name) (gcc version 7.2.1 20171011 (Linaro GCC 7.2-2017.11)) #1 SMP Sat Mar 24 21:23:50 CET 2018
[ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c5387d
[ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[ 0.000000] OF: fdt: Machine model: TI AM335x PocketBeagle
[ 0.000000] Memory policy: Data cache writeback
[ 0.000000] cma: Reserved 16 MiB at 0x9e800000
[ 0.000000] CPU: All CPU(s) started in SVC mode.
[ 0.000000] AM335X ES2.1 (sgx neon)
[ 0.000000] random: fast init done
[ 0.000000] percpu: Embedded 17 pages/cpu @df93f000 s40872 r8192 d20568 u69632
[ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 129412
[ 0.000000] Kernel command line: console=ttyO0,115200n8 root=/dev/mmcblk0p1 rw rootfstype=ext4 rootwait
[ 0.000000] PID hash table entries: 2048 (order: 1, 8192 bytes)
[ 0.000000] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
[ 0.000000] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
[ 0.000000] Memory: 479900K/522240K available (8192K kernel code, 810K rwdata, 2412K rodata, 1024K init, 7547K bss, 25956K reserved, 16384K cma-reserved, 0K highmem)
[ 0.000000] Virtual kernel memory layout:
[ 0.000000] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
[ 0.000000] fixmap : 0xffc00000 - 0xfff00000 (3072 kB)
[ 0.000000] vmalloc : 0xe0000000 - 0xff800000 ( 504 MB)
[ 0.000000] lowmem : 0xc0000000 - 0xdfe00000 ( 510 MB)
[ 0.000000] pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB)
[ 0.000000] modules : 0xbf000000 - 0xbfe00000 ( 14 MB)
[ 0.000000] .text : 0xc0008000 - 0xc0900000 (9184 kB)
[ 0.000000] .init : 0xc0c00000 - 0xc0d00000 (1024 kB)
[ 0.000000] .data : 0xc0d00000 - 0xc0dca9b8 ( 811 kB)
[ 0.000000] .bss : 0xc0dcc000 - 0xc152af94 (7548 kB)
[ 0.000000] Running RCU self tests
[ 0.000000] Hierarchical RCU implementation.
[ 0.000000] RCU event tracing is enabled.
[ 0.000000] RCU lockdep checking is enabled.
[ 0.000000] RCU restricting CPUs from NR_CPUS=2 to nr_cpu_ids=1.
[ 0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1
[ 0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
[ 0.000000] IRQ: Found an INTC at 0xfa200000 (revision 5.0) with 128 interrupts
[ 0.000000] OMAP clockevent source: timer2 at 24000000 Hz
[ 0.000017] sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
[ 0.000044] clocksource: timer1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635851949 ns
[ 0.000097] OMAP clocksource: timer1 at 24000000 Hz
[ 0.000569] timer_probe: no matching timers found
[ 0.001470] Console: colour dummy device 80x30
[ 0.001516] Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar
[ 0.001530] ... MAX_LOCKDEP_SUBCLASSES: 8
[ 0.001542] ... MAX_LOCK_DEPTH: 48
[ 0.001554] ... MAX_LOCKDEP_KEYS: 8191
[ 0.001566] ... CLASSHASH_SIZE: 4096
[ 0.001578] ... MAX_LOCKDEP_ENTRIES: 32768
[ 0.001589] ... MAX_LOCKDEP_CHAINS: 65536
[ 0.001601] ... CHAINHASH_SIZE: 32768
[ 0.001613] memory used by lock dependency info: 4655 kB
[ 0.001626] per task-struct memory footprint: 1536 bytes
[ 0.001663] Calibrating delay loop... 996.14 BogoMIPS (lpj=4980736)
[ 0.078740] pid_max: default: 32768 minimum: 301
[ 0.079147] Security Framework initialized
[ 0.079285] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.079306] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.082392] CPU: Testing write buffer coherency: ok
[ 0.083889] CPU0: thread -1, cpu 0, socket -1, mpidr 0
[ 0.085406] Setting up static identity map for 0x80100000 - 0x80100078
[ 0.085975] Hierarchical SRCU implementation.
[ 0.087625] smp: Bringing up secondary CPUs ...
[ 0.087648] smp: Brought up 1 node, 1 CPU
[ 0.087665] SMP: Total of 1 processors activated (996.14 BogoMIPS).
[ 0.087679] CPU: All CPU(s) started in SVC mode.
[ 0.091643] devtmpfs: initialized
[ 0.116033] VFP support v0.3: implementor 41 architecture 3 part 30 variant c rev 3
[ 0.116853] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[ 0.116916] futex hash table entries: 256 (order: 2, 16384 bytes)
[ 0.118550] pinctrl core: initialized pinctrl subsystem
[ 0.123225] NET: Registered protocol family 16
[ 0.130326] DMA: preallocated 256 KiB pool for atomic coherent allocations
[ 0.171692] omap_hwmod: debugss: _wait_target_disable failed
[ 0.226390] cpuidle: using governor menu
[ 0.237629] OMAP GPIO hardware version 0.1
[ 0.262333] No ATAGs?
[ 0.262360] hw-breakpoint: debug architecture 0x4 unsupported.
[ 0.262655] omap4_sram_init:Unable to allocate sram needed to handle errata I688
[ 0.262675] omap4_sram_init:Unable to get sram pool needed to handle errata I688
[ 0.298256] edma 49000000.edma: TI EDMA DMA engine driver
[ 0.303666] SCSI subsystem initialized
[ 0.305374] omap_i2c 44e0b000.i2c: could not find pctldev for node /ocp/l4_wkup@44c00000/scm@210000/pinmux@800/pinmux_i2c0_pins, deferring probe
[ 0.307447] omap_i2c 4802a000.i2c: bus 1 rev0.11 at 400 kHz
[ 0.307764] omap_i2c 4819c000.i2c: could not find pctldev for node /ocp/l4_wkup@44c00000/scm@210000/pinmux@800/mma8452_pins_default, deferring probe
[ 0.308058] pps_core: LinuxPPS API ver. 1 registered
[ 0.308076] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@linux.it>
[ 0.308128] PTP clock support registered
[ 0.312478] clocksource: Switched to clocksource timer1
[ 0.448001] VFS: Disk quotas dquot_6.6.0
[ 0.448193] VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[ 0.473020] NET: Registered protocol family 2
[ 0.474843] TCP established hash table entries: 4096 (order: 2, 16384 bytes)
[ 0.474948] TCP bind hash table entries: 4096 (order: 5, 147456 bytes)
[ 0.476120] TCP: Hash tables configured (established 4096 bind 4096)
[ 0.476506] UDP hash table entries: 256 (order: 2, 20480 bytes)
[ 0.476689] UDP-Lite hash table entries: 256 (order: 2, 20480 bytes)
[ 0.477446] NET: Registered protocol family 1
[ 0.479566] RPC: Registered named UNIX socket transport module.
[ 0.479614] RPC: Registered udp transport module.
[ 0.479629] RPC: Registered tcp transport module.
[ 0.479643] RPC: Registered tcp NFSv4.1 backchannel transport module.
[ 0.482107] hw perfevents: no interrupt-affinity property for /pmu, guessing.
[ 0.483357] hw perfevents: enabled with armv7_cortex_a8 PMU driver, 5 counters available
[ 0.487455] audit: initializing netlink subsys (disabled)
[ 0.490304] audit: type=2000 audit(0.480:1): state=initialized audit_enabled=0 res=1
[ 0.490640] workingset: timestamp_bits=14 max_order=17 bucket_order=3
[ 0.493682] NFS: Registering the id_resolver key type
[ 0.494058] Key type id_resolver registered
[ 0.494099] Key type id_legacy registered
[ 0.494253] jffs2: version 2.2. (NAND) (SUMMARY) © 2001-2006 Red Hat, Inc.
[ 0.500669] io scheduler noop registered
[ 0.500700] io scheduler deadline registered
[ 0.500822] io scheduler cfq registered (default)
[ 0.500841] io scheduler mq-deadline registered
[ 0.500856] io scheduler kyber registered
[ 0.503256] pinctrl-single 44e10800.pinmux: 142 pins at pa f9e10800 size 568
[ 0.510527] Serial: 8250/16550 driver, 6 ports, IRQ sharing enabled
[ 0.516492] omap_uart 44e09000.serial: no wakeirq for uart0
[ 0.516942] 44e09000.serial: ttyO0 at MMIO 0x44e09000 (irq = 30, base_baud = 3000000) is a OMAP UART0
[ 1.250345] console [ttyO0] enabled
[ 1.255586] omap_uart 48022000.serial: no wakeirq for uart1
[ 1.261829] 48022000.serial: ttyO1 at MMIO 0x48022000 (irq = 31, base_baud = 3000000) is a OMAP UART1
[ 1.272744] omap_uart 48024000.serial: no wakeirq for uart2
[ 1.278844] 48024000.serial: ttyO2 at MMIO 0x48024000 (irq = 32, base_baud = 3000000) is a OMAP UART2
[ 1.289570] omap_uart 481a8000.serial: no wakeirq for uart4
[ 1.295781] 481a8000.serial: ttyO4 at MMIO 0x481a8000 (irq = 33, base_baud = 3000000) is a OMAP UART4
[ 1.334046] brd: module loaded
[ 1.362138] loop: module loaded
[ 1.368162] mtdoops: mtd device (mtddev=name/number) must be supplied
[ 1.383297] libphy: Fixed MDIO Bus: probed
[ 1.390588] i2c /dev entries driver
[ 1.398755] omap_hsmmc 48060000.mmc: Got CD GPIO
[ 1.465093] ledtrig-cpu: registered to indicate activity on CPUs
[ 1.472542] oprofile: using arm/armv7
[ 1.477095] Initializing XFRM netlink socket
[ 1.481985] NET: Registered protocol family 10
[ 1.493215] Segment Routing with IPv6
[ 1.497190] sit: IPv6, IPv4 and MPLS over IPv4 tunneling driver
[ 1.505262] NET: Registered protocol family 17
[ 1.509973] NET: Registered protocol family 15
[ 1.515090] Key type dns_resolver registered
[ 1.519724] omap_voltage_late_init: Voltage driver support not added
[ 1.526481] sr_dev_init: No voltage domain specified for smartreflex0. Cannot initialize
[ 1.535007] sr_dev_init: No voltage domain specified for smartreflex1. Cannot initialize
[ 1.543566] ThumbEE CPU extension supported.
[ 1.548049] Registering SWP/SWPB emulation handler
[ 1.553116] SmartReflex Class3 initialized
[ 1.623490] mmc0: host does not support reading read-only switch, assuming write-enable
[ 1.635560] mmc0: new high speed SDHC card at address 0007
[ 1.644119] mmcblk0: mmc0:0007 SD32G 28.8 GiB
[ 1.655081] mmcblk0: p1 p2
[ 1.671199] tps65217 0-0024: TPS65217 ID 0xe version 1.2
[ 1.677649] omap_i2c 44e0b000.i2c: bus 0 rev0.11 at 400 kHz
[ 1.686633] omap_i2c 4819c000.i2c: bus 2 rev0.11 at 400 kHz
[ 1.694194] hctosys: unable to open rtc device (rtc0)
[ 1.699490] sr_init: No PMIC hook to init smartreflex
[ 1.705144] sr_init: platform driver register failed for SR
[ 1.720670] List of all partitions:
[ 1.724586] 0100 16384 ram0
[ 1.724597] (driver?)
[ 1.730999] 0101 16384 ram1
[ 1.731008] (driver?)
[ 1.737842] 0102 16384 ram2
[ 1.737854] (driver?)
[ 1.744389] 0103 16384 ram3
[ 1.744400] (driver?)
[ 1.750791] 0104 16384 ram4
[ 1.750800] (driver?)
[ 1.757269] 0105 16384 ram5
[ 1.757278] (driver?)
[ 1.763737] 0106 16384 ram6
[ 1.763746] (driver?)
[ 1.770139] 0107 16384 ram7
[ 1.770148] (driver?)
[ 1.776597] 0108 16384 ram8
[ 1.776607] (driver?)
[ 1.783061] 0109 16384 ram9
[ 1.783071] (driver?)
[ 1.789456] 010a 16384 ram10
[ 1.789465] (driver?)
[ 1.795999] 010b 16384 ram11
[ 1.796008] (driver?)
[ 1.802540] 010c 16384 ram12
[ 1.802549] (driver?)
[ 1.809029] 010d 16384 ram13
[ 1.809038] (driver?)
[ 1.815571] 010e 16384 ram14
[ 1.815580] (driver?)
[ 1.822056] 010f 16384 ram15
[ 1.822065] (driver?)
[ 1.828679] b300 30228480 mmcblk0
[ 1.828690] driver: mmcblk
[ 1.835867] b301 16384 mmcblk0p1 00000000-01
[ 1.835877]
[ 1.843044] b302 524288 mmcblk0p2 00000000-02
[ 1.843053]
[ 1.850164] No filesystem could mount root, tried:
[ 1.850173] ext4
[ 1.855340]
[ 1.858913] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,1)
[ 1.867873] ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,1)
答案 0 :(得分：3)
由于未指定SD卡的正确分区，因此无法安装rootfs 在内核命令行中，（错误地）指示内核在 / dev / mmcblk0p1 对应的分区中查找rootfs。
bootargs=console=ttyO0,115200n8 root=/dev/mmcblk0p1 rw rootfstype=ext4 rootwait
和
[ 0.000000] Kernel command line: console=ttyO0,115200n8 root=/dev/mmcblk0p1 rw rootfstype=ext4 rootwait
但是，mmc子系统报告SD卡上有两个分区，并且启动日志为您两次报告这些分区的设备名称。
第一：
[ 1.635560] mmc0: new high speed SDHC card at address 0007
[ 1.644119] mmcblk0: mmc0:0007 SD32G 28.8 GiB
[ 1.655081] mmcblk0: p1 p2
然后：
[ 1.720670] List of all partitions:
...
[ 1.828679] b300 30228480 mmcblk0
[ 1.828690] driver: mmcblk
[ 1.835867] b301 16384 mmcblk0p1 00000000-01
[ 1.835877]
[ 1.843044] b302 524288 mmcblk0p2 00000000-02
因此，内核命令行（通过 bootargs ）应指定第二个分区 / dev / mmcblk0p2 ，而不是rootfs的第一个分区。
由于U-Boot环境的存储区域尚未正确初始化（即“警告 - 错误的CRC，使用默认环境”消息）（或 uEnv.txt < / strong>文件丢失或损坏），U-Boot正在使用您的主板配置文件中定义的硬编码 bootargs 值启动Linux内核。
您可以编辑该文件并重新构建U-Boot，也可以中止自动引导并使用
setenv bootargs console=ttyO0,115200n8 root=/dev/mmcblk0p2 rw rootfstype=ext4 rootwait和saveenv命令可以纠正这种错误的说明。