init: DEBUG_BLOCK_EXT_DEVT requires explicit root= param (55dc7db7) · Commits · 戴 / test

DEBUG_BLOCK_EXT_DEVT shuffles SCSI and IDE device numbers and root device number set using rdev become meaningless. Root devices should be explicitly specified using textual names. Warn about it if root can't be found and DEBUG_BLOCK_EXT_DEVT is enabled. Also, add warning to the help text. Signed-off-by:

Tejun Heo <tj@kernel.org> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Signed-off-by:

Jens Axboe <jens.axboe@oracle.com>

init/do_mounts.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -263,6 +263,10 @@ retry:
		printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");

		printk_all_partitions();
		#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
		printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
		"explicit textual name for \"root=\" boot option.\n");
		#endif
		panic("VFS: Unable to mount root fs on %s", b);
		}

lib/Kconfig.debug

+6 −0

Original line number	Diff line number	Diff line
		@@ -638,6 +638,12 @@ config DEBUG_BLOCK_EXT_DEVT
		userland code paths which assume predetermined contiguous
		device number allocation.

		Note that turning on this debug option shuffles all the
		device numbers for all IDE and SCSI devices including libata
		ones, so root partition specified using device number
		directly (via rdev or root=MAJ:MIN) won't work anymore.
		Textual device names (root=/dev/sdXn) will continue to work.

		Say N if you are unsure.

		config LKDTM

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