解决那些千奇百怪的 Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block 错误

柚木鉉 LV 9

传言道：80%的 Kernel panic 是都是同一个报错：

剩下 5% 是 init 设置错了，其余的是剩余各式各样的

---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block ]---

所以开个帖子，记录下遇到的那些奇奇怪怪的 VFS Panic 和解决方法

柚木鉉 LV 9

错误列表【持续更新中】

[EXFAT] trying to mount...并打印分区表：https://bbs.aw-ol.com/topic/1726/share/3
打印分区表出现 No filesystem could mount root, tried: xxx ：https://bbs.aw-ol.com/topic/1726/share/4
eMMC、TF卡、SDNAND启动卡在 Waiting for root device /dev/ubiblockxxx... 不动了：https://bbs.aw-ol.com/topic/1726/share/5
SPI NAND、SPI NOR 启动卡在 Waiting for root device /dev/ubiblockxxx... 不动了：https://bbs.aw-ol.com/topic/1726/share/6
rootfs格式设置都是正确的但是还是打印分区表然后 No filesystem could mount root, tried: xxx ：https://bbs.aw-ol.com/topic/1726/share/7
报错 Filesystem uses "xz" compression. This is not supported：https://bbs.aw-ol.com/topic/1726/share/8

柚木鉉 LV 9

错误

设备：T113 + eMMC，SDC2
错误描述：[EXFAT] trying to mount... 后 Panic，显示 MMC 分区表

LOG

[    2.345878] [EXFAT] trying to mount...
[    2.350344] VFS: Cannot open root device "mmcblk0p5" or unknown-block(179,5): error -5
[    2.359283] Please append a correct "root=" boot option; here are the available partitions:
[    2.368687] b300        15392768 mmcblk0
[    2.368690]  driver: mmcblk
[    2.376362]   b301           17219 mmcblk0p1 a0085546-4166-744a-a353-fca9272b8e45
[    2.376366]
[    2.386443]   b302            1024 mmcblk0p2 a0085546-4166-744a-a353-fca9272b8e46
[    2.386446]
[    2.396519]   b303            1024 mmcblk0p3 a0085546-4166-744a-a353-fca9272b8e47
[    2.396521]
[    2.406588]   b304           16384 mmcblk0p4 a0085546-4166-744a-a353-fca9272b8e48
[    2.406590]
[    2.416657]   b305           16384 mmcblk0p5 a0085546-4166-744a-a353-fca9272b8e49
[    2.416659]
[    2.426726]   b306            1024 mmcblk0p6 a0085546-4166-744a-a353-fca9272b8e4a
[    2.426728]
[    2.436797]   b307        15302828 mmcblk0p7 a0085546-4166-744a-a353-fca9272b8e4b
[    2.436799]
[    2.446875] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,5)
[    2.456348] CPU0: stopping
[    2.459386] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.61+ #3
[    2.466119] Hardware name: Generic DT based system
[    2.471515] [<c010e048>] (unwind_backtrace) from [<c010a788>] (show_stack+0x10/0x14)
[    2.480206] [<c010a788>] (show_stack) from [<c05f93e8>] (dump_stack+0x88/0xa4)
[    2.488313] [<c05f93e8>] (dump_stack) from [<c010c3d8>] (handle_IPI+0xd4/0x180)
[    2.496518] [<c010c3d8>] (handle_IPI) from [<c0329cbc>] (gic_handle_irq+0x70/0x78)
[    2.505016] [<c0329cbc>] (gic_handle_irq) from [<c01021cc>] (__irq_svc+0x6c/0xa8)
[    2.513408] Exception stack(0xc0b01f40 to 0xc0b01f88)
[    2.519077] 1f40: 000008d0 c7aba334 00000000 c01149c0 00000001 c0b00000 c0b03de4 c0b03e20
[    2.528253] 1f60: 00000000 c7bff5c0 c0a240c0 00000000 00000001 c0b01f90 c01080a0 c01080a4
[    2.537424] 1f80: 60000113 ffffffff
[    2.541342] [<c01021cc>] (__irq_svc) from [<c01080a4>] (arch_cpu_idle+0x2c/0x38)
[    2.549643] [<c01080a4>] (arch_cpu_idle) from [<c013dbe4>] (do_idle+0xbc/0x128)
[    2.557845] [<c013dbe4>] (do_idle) from [<c013dee0>] (cpu_startup_entry+0x18/0x20)
[    2.566344] [<c013dee0>] (cpu_startup_entry) from [<c0a00c80>] (start_kernel+0x354/0x3e0)
[    2.575520] [<c0a00c80>] (start_kernel) from [<00000000>] (0x0)
[    2.582170] ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,5) ]---

解决

看到 [EXFAT] trying to mount... 不用慌，这只是一个障眼法，它真正的报错是 No filesystem could mount root, tried: xxx 也就是没有找到可以挂载的格式。

因为 EXFAT 的驱动很特别，他一般是之前设置的格式都没法挂载后才会尝试 EXFAT。所以实际上错误与下一个要介绍的错误是相同的。

建议关闭 exfat 看看真正的报错是什么

柚木鉉 LV 9

错误

设备：T113 + eMMC，SDC2
错误描述：显示分区表后 Panic，提示没有可供挂载的格式

LOG

[    2.337965] List of all partitions:
[    2.341882] b300        15392768 mmcblk0
[    2.341885]  driver: mmcblk
[    2.349544]   b301           17219 mmcblk0p1 a0085546-4166-744a-a353-fca9272b8e45
[    2.349547]
[    2.359627]   b302            1024 mmcblk0p2 a0085546-4166-744a-a353-fca9272b8e46
[    2.359630]
[    2.369712]   b303            1024 mmcblk0p3 a0085546-4166-744a-a353-fca9272b8e47
[    2.369714]
[    2.379784]   b304           16384 mmcblk0p4 a0085546-4166-744a-a353-fca9272b8e48
[    2.379786]
[    2.389853]   b305           42232 mmcblk0p5 a0085546-4166-744a-a353-fca9272b8e49
[    2.389855]
[    2.399921]   b306            1024 mmcblk0p6 a0085546-4166-744a-a353-fca9272b8e4a
[    2.399923]
[    2.409989]   b307        15302828 mmcblk0p7 a0085546-4166-744a-a353-fca9272b8e4b
[    2.409992]
[    2.420057] No filesystem could mount root, tried:
[    2.429837]  squashfs
[    2.434530]
[    2.438364] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,5)
[    2.447834] CPU0: stopping
[    2.450871] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.61+ #4
[    2.457595] Hardware name: Generic DT based system
[    2.462990] [<c010e048>] (unwind_backtrace) from [<c010a788>] (show_stack+0x10/0x14)
[    2.471682] [<c010a788>] (show_stack) from [<c05ece28>] (dump_stack+0x88/0xa4)
[    2.479789] [<c05ece28>] (dump_stack) from [<c010c3d8>] (handle_IPI+0xd4/0x180)
[    2.487994] [<c010c3d8>] (handle_IPI) from [<c0329cbc>] (gic_handle_irq+0x70/0x78)
[    2.496491] [<c0329cbc>] (gic_handle_irq) from [<c01021cc>] (__irq_svc+0x6c/0xa8)
[    2.504883] Exception stack(0xc0b01f40 to 0xc0b01f88)
[    2.510552] 1f40: 00000a3c c7aba334 00000000 c01149c0 00000001 c0b00000 c0b03de4 c0b03e20
[    2.519728] 1f60: 00000000 c7bff5c0 c0a240c0 00000000 c0b4b7e8 c0b01f90 c01080a0 c01080a4
[    2.528900] 1f80: 60000113 ffffffff
[    2.532816] [<c01021cc>] (__irq_svc) from [<c01080a4>] (arch_cpu_idle+0x2c/0x38)
[    2.541118] [<c01080a4>] (arch_cpu_idle) from [<c013dbe4>] (do_idle+0xbc/0x128)
[    2.549321] [<c013dbe4>] (do_idle) from [<c013dee0>] (cpu_startup_entry+0x18/0x20)
[    2.557819] [<c013dee0>] (cpu_startup_entry) from [<c0a00c80>] (start_kernel+0x354/0x3e0)
[    2.566996] [<c0a00c80>] (start_kernel) from [<00000000>] (0x0)
[    2.573643] ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,5) ]---

解决

检查下你的 rootfs 的格式，这里只支持 squashfs 看看你的 rootfs 是不是打包成 ext4 或者是其他什么格式的了。

柚木鉉 LV 9

错误：

设备 T113 + eMMC，SDC2
错误描述：卡在 Waiting for root device /dev/ubiblock0_5... 不动了

LOG

[    3.793291] Waiting for root device /dev/ubiblock0_5...
[    3.836994] random: crng init done
[    6.927839]
[    6.927839] insmod_device_driver
[    6.927839]

解决

看设备名：ubiblock0_5，ubixxxx 表示这是一个 SPI NAND 设备，如果是 SPI NOR 那一般是 mtdxxxx。
再看看我们实际的启动设备，是eMMC，是一个MMC设备，应该是 mmcblkxxx 这样的才对
检查下 bootargs 里的参数，看看 root= 后面是不是设置成 SPI FLASH 了

柚木鉉 LV 9

错误：

设备 T113 + SPI NAND，SPI 0
错误描述：卡在 Waiting for root device /dev/ubiblock0_5... 不动了

LOG

[    3.793291] Waiting for root device /dev/ubiblock0_5...
[    3.836994] random: crng init done
[    6.927839]
[    6.927839] insmod_device_driver
[    6.927839]

解决

看设备名：ubiblock0_5，ubixxxx 表示这是一个 SPI NAND 设备，如果是 SPI NOR 那一般是 mtdxxxx。
再看看我们实际的启动设备，也是 SPI NAND，那这里就对上了。
再看看咋们的设备树：

好嘛，你把 SPI0 都 disable 了他咋启动啊，设置 okay 就好了

柚木鉉 LV 9

错误

设备：T113 + eMMC，SDC2
错误描述：rootfs格式设置都是正确的，驱动也有，但是还是打印分区表然后提示没有可供挂载的格式

LOG

[    2.337965] List of all partitions:
[    2.341882] b300        15392768 mmcblk0
[    2.341885]  driver: mmcblk
[    2.349544]   b301           17219 mmcblk0p1 a0085546-4166-744a-a353-fca9272b8e45
[    2.349547]
[    2.359627]   b302            1024 mmcblk0p2 a0085546-4166-744a-a353-fca9272b8e46
[    2.359630]
[    2.369712]   b303            1024 mmcblk0p3 a0085546-4166-744a-a353-fca9272b8e47
[    2.369714]
[    2.379784]   b304           16384 mmcblk0p4 a0085546-4166-744a-a353-fca9272b8e48
[    2.379786]
[    2.389853]   b305           16384 mmcblk0p5 a0085546-4166-744a-a353-fca9272b8e49
[    2.389855]
[    2.399921]   b306            1024 mmcblk0p6 a0085546-4166-744a-a353-fca9272b8e4a
[    2.399923]
[    2.409989]   b307        15302828 mmcblk0p7 a0085546-4166-744a-a353-fca9272b8e4b
[    2.409992]
[    2.420057] No filesystem could mount root, tried:
[    2.420059]  ext3
[    2.425525]  ext2
[    2.427686]  ext4
[    2.429837]  squashfs
[    2.431988]  vfat
[    2.434530]
[    2.438364] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,5)
[    2.447834] CPU0: stopping
[    2.450871] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.61+ #4
[    2.457595] Hardware name: Generic DT based system
[    2.462990] [<c010e048>] (unwind_backtrace) from [<c010a788>] (show_stack+0x10/0x14)
[    2.471682] [<c010a788>] (show_stack) from [<c05ece28>] (dump_stack+0x88/0xa4)
[    2.479789] [<c05ece28>] (dump_stack) from [<c010c3d8>] (handle_IPI+0xd4/0x180)
[    2.487994] [<c010c3d8>] (handle_IPI) from [<c0329cbc>] (gic_handle_irq+0x70/0x78)
[    2.496491] [<c0329cbc>] (gic_handle_irq) from [<c01021cc>] (__irq_svc+0x6c/0xa8)
[    2.504883] Exception stack(0xc0b01f40 to 0xc0b01f88)
[    2.510552] 1f40: 00000a3c c7aba334 00000000 c01149c0 00000001 c0b00000 c0b03de4 c0b03e20
[    2.519728] 1f60: 00000000 c7bff5c0 c0a240c0 00000000 c0b4b7e8 c0b01f90 c01080a0 c01080a4
[    2.528900] 1f80: 60000113 ffffffff
[    2.532816] [<c01021cc>] (__irq_svc) from [<c01080a4>] (arch_cpu_idle+0x2c/0x38)
[    2.541118] [<c01080a4>] (arch_cpu_idle) from [<c013dbe4>] (do_idle+0xbc/0x128)
[    2.549321] [<c013dbe4>] (do_idle) from [<c013dee0>] (cpu_startup_entry+0x18/0x20)
[    2.557819] [<c013dee0>] (cpu_startup_entry) from [<c0a00c80>] (start_kernel+0x354/0x3e0)
[    2.566996] [<c0a00c80>] (start_kernel) from [<00000000>] (0x0)
[    2.573643] ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,5) ]---

解决

这一般是因为 rootfs 的数据错误，看一下是不是打包错了，把uboot打包进rootfs里了，或者是root=的分区搞错了，或者 rootfs 因为不正常关机损坏了

比如这里，mmcblk0p4 与 mmcblk0p5 容量一模一样的，肯定是打包错了

柚木鉉 LV 9

错误

设备：T113 + TF 卡，SDC0
错误描述：rootfs格式设置都是正确的，驱动也有，报错 Filesystem uses "xz" compression. This is not supported

LOG

[    4.049960] Filesystem uses "xz" compression. This is not supported
[    4.058133] [EXFAT] trying to mount...
[    4.062717] VFS: Cannot open root device "mmcblk0p5" or unknown-block(179,5): error -5
[    4.071559] Please append a correct "root=" boot option; here are the available partitions:
[    4.080869] b300        30253056 mmcblk0
[    4.080872]  driver: mmcblk
[    4.088504]   b301             252 mmcblk0p1 a0085546-4166-744a-a353-fca9272b8e45
[    4.088507]
[    4.098521]   b302             252 mmcblk0p2 a0085546-4166-744a-a353-fca9272b8e46
[    4.098524]
[    4.108544]   b303             252 mmcblk0p3 a0085546-4166-744a-a353-fca9272b8e47
[    4.108547]
[    4.118568]   b304            8316 mmcblk0p4 a0085546-4166-744a-a353-fca9272b8e48
[    4.118570]
[    4.128581]   b305           30992 mmcblk0p5 a0085546-4166-744a-a353-fca9272b8e49
[    4.128583]
[    4.138575]   b306        30176111 mmcblk0p6 a0085546-4166-744a-a353-fca9272b8e4a
[    4.138577]
[    4.148600] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,5)
[    4.158014] CPU0: stopping
[    4.161030] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.61+ #1
[    4.167708] Hardware name: Generic DT based system
[    4.173059] [<c010e048>] (unwind_backtrace) from [<c010a788>] (show_stack+0x10/0x14)
[    4.181681] [<c010a788>] (show_stack) from [<c05f9108>] (dump_stack+0x88/0xa4)
[    4.189727] [<c05f9108>] (dump_stack) from [<c010c3d8>] (handle_IPI+0xd4/0x180)
[    4.197865] [<c010c3d8>] (handle_IPI) from [<c03299e4>] (gic_handle_irq+0x70/0x78)
[    4.206291] [<c03299e4>] (gic_handle_irq) from [<c01021cc>] (__irq_svc+0x6c/0xa8)
[    4.214611] Exception stack(0xc0b01f40 to 0xc0b01f88)
[    4.220234] 1f40: 00000c60 c7abb334 00000000 c01149c0 00000001 c0b00000 c0b03de4 c0b03e20
[    4.229331] 1f60: 00000000 c7bff5c0 c0a240c0 00000000 00000001 c0b01f90 c01080a0 c01080a4
[    4.238429] 1f80: 60000113 ffffffff
[    4.242314] [<c01021cc>] (__irq_svc) from [<c01080a4>] (arch_cpu_idle+0x2c/0x38)
[    4.250551] [<c01080a4>] (arch_cpu_idle) from [<c013dbe4>] (do_idle+0xbc/0x128)
[    4.258686] [<c013dbe4>] (do_idle) from [<c013dee0>] (cpu_startup_entry+0x18/0x20)
[    4.267114] [<c013dee0>] (cpu_startup_entry) from [<c0a00c80>] (start_kernel+0x354/0x3e0)
[    4.276219] [<c0a00c80>] (start_kernel) from [<00000000>] (0x0)
[    4.282806] ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,5) ]---

解决

Filesystem uses "xz" compression. This is not supported

SquashFS 不支持这个压缩格式

丢脸，看看你的 kernel menuconfig 里有没有打开 xz 压缩了，这不没开的嘛

efancier LV 6

@yuzukitsuru ,好帖

damifan110 LV 5

@yuzukitsuru 我要是不回复感谢一下，我都觉得对不起你…

lovexulu LV 7

发现一种同样的报错，原因是卡启动det引脚电平不对！这个硬件错误也会导致同样的报错。

soso90 LV 7

还有一种是tf卡太差，有时候就挂了。。

Maihuanyi LV 5

@yuzukitsuru D1s关闭sdc1的设备树，出现下面的报错，怎么解决？

VFS: Cannot open root device "mmcblk0p5" or unknown-block(0,0): error -6
Please append a correct "root=" boot option; here are the available partitions:
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
CPU: 0 PID: 1 Comm: swapper Not tainted 5.4.61 #128
Call Trace:
[<ffffffe000020164>] walk_stackframe+0x0/0x98
[<ffffffe00002031c>] show_stack+0x2a/0x34
[<ffffffe0002f05cc>] dump_stack+0x20/0x28
[<ffffffe000024724>] panic+0xec/0x272
[<ffffffe000000ef2>] mount_block_root+0x214/0x27a
[<ffffffe000000fde>] mount_root+0x86/0x90
[<ffffffe000001130>] prepare_namespace+0x148/0x152
[<ffffffe000000b54>] kernel_init_freeable+0x166/0x198
[<ffffffe000300d30>] kernel_init+0x12/0xee
[<ffffffe00001eed0>] ret_from_exception+0x0/0xc
---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) ]---

whycan晕哥 LV 9

@maihuanyi
没有生成 /dev/mmcblk0p5 ？

Maihuanyi LV 5

@whycan 是的，谢谢

whycan晕哥 LV 9

@maihuanyi
注意sdc0 TF卡的det引脚的电平，看下是高检测，还是低检测，如果反了Linux就检测不到卡片。

Maihuanyi LV 5

@maihuanyi 在lichee/linux-5.4/drivers/staging/exfat/exfat_super.c的4027行添加延时，如下图所示
主要问题是exFAT初始化过快，需要等sd初始化完成，再初始化exFAT文件系统。