From 6aee6723f1b3a4453b327fdafcde362e9befcc11 Mon Sep 17 00:00:00 2001 From: Angus Chen Date: Thu, 18 May 2023 11:53:21 +0800 Subject: [PATCH] init: add bdev fs printk if mount_block_root failed 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] [ 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. [akpm@linux-foundation.org: fix spelling in printk message] Link: https://lkml.kernel.org/r/20230518035321.1672-1-angus.chen@jaguarmicro.com Signed-off-by: Angus Chen Acked-by: Nick Desaulniers Cc: Masahiro Yamada Cc: Mike Rapoport (IBM) Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Vlastimil Babka Cc: Al Viro Signed-off-by: Andrew Morton --- init/do_mounts.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/init/do_mounts.c b/init/do_mounts.c index 83447c46ad6d..9b66667eeea6 100644 --- a/init/do_mounts.c +++ b/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 filesystems:\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)) {