Hi all,
My embedded development box fails to NFS-boot with NFS server which uses recent
kernel.
Using git bisect, I found it is caused by commit 4bdc33ed ("NFSDv4.2: Add NFS
v4.2 support to the NFS server").
1. dmesg (NFS boot failure case)
...
[ 2.040893] ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 2.046207] e1000: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control:
RX
[ 2.053570] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[ 3.055023] IP-Config: Guessing netmask 255.255.0.0
[ 3.059979] IP-Config: Gateway not on directly connected network.
[ 3.066330] Looking up port of RPC 100003/2 on 165.213.88.249
[ 3.074001] Looking up port of RPC 100005/1 on 165.213.88.249
[ 3.122878] VFS: Unable to mount root fs via NFS, trying floppy.
[ 3.129134] VFS: Cannot open root device "nfs" or unknown-block(2,0)
[ 3.135478] Please append a correct "root=" boot option; here are the
available partitions:
[ 3.143831] 1f00 3072 mtdblock0 (driver?)
[ 3.148798] 1f01 64 mtdblock1 (driver?)
[ 3.153758] 1f02 64 mtdblock2 (driver?)
[ 3.158719] 1f03 64 mtdblock3 (driver?)
[ 3.163682] 1f04 64 mtdblock4 (driver?)
[ 3.168644] 1f05 64 mtdblock5 (driver?)
[ 3.173607] 1f06 64 mtdblock6 (driver?)
[ 3.178568] 0800 488386584 sda driver: sd
[ 3.183099] 0801 506016 sda1
[ 3.186927] 0802 4008217 sda2
[ 3.190755] 0803 483869767 sda3
[ 3.194584] b300 1880064 mmcblk0 driver: mmcblk
[ 3.199802] b301 4096 mmcblk0p1
[ 3.204063] b302 102400 mmcblk0p2
[ 3.208330] b303 4096 mmcblk0p3
[ 3.212594] b304 1 mmcblk0p4
[ 3.216855] b305 2048 mmcblk0p5
[ 3.221116] b306 2048 mmcblk0p6
[ 3.225382] b307 2048 mmcblk0p7
[ 3.229644] b308 4096 mmcblk0p8
[ 3.233906] b309 12288 mmcblk0p9
[ 3.238176] b30a 16384 mmcblk0p10
[ 3.242524] b30b 142336 mmcblk0p11
[ 3.246869] b30c 1572864 mmcblk0p12
[ 3.251219] b320 12288 mmcblk0gp1 (driver?)
[ 3.256272] b310 12288 mmcblk0gp0 (driver?)
[ 3.261320] Kernel panic - not syncing: VFS: Unable to mount root fs on
unknown-block(2,0)
[ 3.269566] Pid: 1, comm: swapper Not tainted 2.6.35 #1
[ 3.274776] Call Trace:
[ 3.277232] [<80d0db5b>] ? printk+0x1e/0x20
[ 3.281492] [<80d0dad1>] panic+0x65/0xd1
[ 3.285495] [<80eb9ce3>] mount_block_root+0x125/0x1be
[ 3.290631] [<809d1f6d>] ? sys_mknod+0x2d/0x30
[ 3.295156] [<80eb9f6d>] mount_root+0xd0/0xf2
[ 3.299591] [<80eba0d9>] prepare_namespace+0x14a/0x184
[ 3.304803] [<809c44f6>] ? sys_access+0x26/0x30
[ 3.309411] [<80eb9a4e>] kernel_init+0x25e/0x26e
[ 3.314105] [<80eb97f0>] ? kernel_init+0x0/0x26e
[ 3.318800] [<80903242>] kernel_thread_helper+0x6/0x10
2. Client (my embedded box) configuration
It's kernel 2.6.35 based, and has following NFS kernel configs.
# grep NFS .config
CONFIG_NFS_FS=y
CONFIG_NFS_V3=y
CONFIG_NFS_V3_ACL=y
CONFIG_NFS_V4=y
# CONFIG_NFS_V4_1 is not set
CONFIG_ROOT_NFS=y
# CONFIG_NFSD is not set
CONFIG_NFS_ACL_SUPPORT=y
CONFIG_NFS_COMMON=y
3. Server (NFSD) configuration
Fedora 19 + latest linus git kernel 3.12.0-rc2+ (commit 22356f44, mm: Place
preemption point in do_mlockall() loop)
4. workaround
Reverting the commit 4bdc33ed resolves my issue, NFS boot is working then.
I've done git bisect, but lost the resulting bisect log due to sudden power
loss :(.
Best regards,
Jongman Heo
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