The patch titled
Subject: init: add bdev fs printk if mount_block_root failed
has been added to the -mm mm-nonmm-unstable branch. Its filename is
init-add-bdev-fs-printk-if-mount_block_root-failed.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/init-add-bdev-fs-printk-if-mount_block_root-failed.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Angus Chen <angus.chen@xxxxxxxxxxxxxxx>
Subject: init: add bdev fs printk if mount_block_root failed
Date: Thu, 18 May 2023 11:53:21 +0800
Booting with the QEMU command line:
"qemu-system-x86_64 -append root=/dev/vda rootfstype=ext4 ..."
will panic if ext4 is not builtin and a request to load the ext4 module
fails.
[ 1.729006] VFS: Cannot open root device "vda" or unknown-block(253,0): error -19
[ 1.730603] Please append a correct "root=" boot option; here are the available partitions:
[ 1.732323] fd00 256000 vda
[ 1.732329] driver: virtio_blk
[ 1.734194] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(253,0)
[ 1.734771] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.4.0-rc2+ #53
[ 1.735194] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-1ubuntu1 04/01/2014
[ 1.735772] Call Trace:
[ 1.735950] <TASK>
[ 1.736113] dump_stack_lvl+0x32/0x50
[ 1.736367] panic+0x108/0x310
[ 1.736570] mount_block_root+0x161/0x310
[ 1.736849] ? rdinit_setup+0x40/0x40
[ 1.737088] prepare_namespace+0x10c/0x180
[ 1.737393] kernel_init_freeable+0x354/0x450
[ 1.737707] ? rest_init+0xd0/0xd0
[ 1.737945] kernel_init+0x16/0x130
[ 1.738196] ret_from_fork+0x1f/0x30
As a hint, print all the bdev fstypes which are available.
Link: https://lkml.kernel.org/r/20230518035321.1672-1-angus.chen@xxxxxxxxxxxxxxx
Signed-off-by: Angus Chen <angus.chen@xxxxxxxxxxxxxxx>
Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Cc: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
init/do_mounts.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
--- a/init/do_mounts.c~init-add-bdev-fs-printk-if-mount_block_root-failed
+++ a/init/do_mounts.c
@@ -427,8 +427,19 @@ retry:
printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
root_device_name, b, err);
printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
-
printk_all_partitions();
+
+ if (root_fs_names)
+ num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
+ if (!num_fs)
+ pr_err("Can't find any bdev filesystem to be used for mount!\n");
+ else {
+ pr_err("List of all bdev filesystem:\n");
+ for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
+ pr_err(" %s", p);
+ pr_err("\n");
+ }
+
panic("VFS: Unable to mount root fs on %s", b);
}
if (!(flags & SB_RDONLY)) {
_
Patches currently in -mm which might be from angus.chen@xxxxxxxxxxxxxxx are
init-add-bdev-fs-printk-if-mount_block_root-failed.patch
