If there is no valid initrd, but root=UUID or root=LABEL is used in the command line, boot hangs like this: [ 5.739815] VFS: Cannot open root device "UUID=19957230-2e15-494c-8dfa-84aab3591961" or unknown-block(0,0): error -6 [ 5.750280] Please append a correct "root=" boot option; here are the available partitions: [ 5.856059] 0800 125034840 sda [ 5.856061] driver: sd [ 5.862124] 0801 307200 sda1 d5077411-3d87-4f85-b312-8cc309ef9073 [ 5.862128] [ 5.870603] 0802 1048576 sda2 aae0dd30-e5f5-44e1-994e-d47bf5ce2e52 [ 5.870606] [ 5.879080] 0803 52428800 sda3 759079ee-85fa-4636-9de7-1ac0643ab87e [ 5.879083] [ 5.887558] 0804 8388608 sda4 439c4b0a-7b4f-4434-82f1-f9d380b55fb9 [ 5.887560] [ 5.896035] 0805 62860288 sda5 ee52e951-1315-4fab-a3e5-45c6eeae6ce6 [ 5.910575] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) [ 5.918796] ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) ]--- The above log is very useful, but some users still need time to analysis the cause [1, 2]. It is better to print some info to explicitly tell the users root=UUID or root=LABEL is not supported without initrd. [1] https://unix.stackexchange.com/questions/93767/why-cant-i-specify-my-root-fs-with-a-uuid [2] https://unix.stackexchange.com/questions/302795/how-to-identify-root-partition-via-uuid-without-initramfs-initrd Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> --- init/do_mounts.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/init/do_mounts.c b/init/do_mounts.c index 7058e14..2c1c492 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -290,6 +290,14 @@ dev_t name_to_dev_t(const char *name) if (strncmp(name, "/dev/", 5) == 0) return devt_from_devname(name + 5); #endif + if (strncmp(name, "UUID=", 5) == 0) { + pr_info("root=UUID is not supported without initrd\n"); + return 0; + } + if (strncmp(name, "LABEL=", 6) == 0) { + pr_info("root=LABEL is not supported without initrd\n"); + return 0; + } return devt_from_devnum(name); } EXPORT_SYMBOL_GPL(name_to_dev_t); -- 2.1.0
