Greeting,

FYI, we noticed the following commit (built with gcc-9):

commit: 7b81ce7cdcef3a3ae71eb3fb863433c646b4a2f4 ("init: fix error check in clean_path()")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master


in testcase: trinity
version: trinity-x86_64-af355e9-1_2019-12-03
with following parameters:

	runtime: 300s

test-description: Trinity is a linux system call fuzz tester.
test-url: http://codemonkey.org.uk/projects/trinity/


on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 8G

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):


+----------------------------------------------------------------------------+------------+------------+
|                                                                            | 59126901f2 | 7b81ce7cdc |
+----------------------------------------------------------------------------+------------+------------+
| boot_successes                                                             | 4          | 0          |
| boot_failures                                                              | 0          | 4          |
| Kernel_panic-not_syncing:VFS:Unable_to_mount_root_fs_on_unknown-block(#,#) | 0          | 4          |
+----------------------------------------------------------------------------+------------+------------+


If you fix the issue, kindly add following tag
Reported-by: kernel test robot <rong.a.chen@intel.com>


[   20.510089]   #0: Dummy 1
[   20.510601]   #1: Loopback 1
[   20.511133]   #2: MTPAV on parallel port at 0x378
[   20.512642] VFS: Cannot open root device "ram0" or unknown-block(0,0): error -6
[   20.514315] Please append a correct "root=" boot option; here are the available partitions:
[   20.515530] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
[   20.516725] CPU: 0 PID: 1 Comm: swapper Not tainted 5.9.0-rc3-00224-g7b81ce7cdcef3 #1
[   20.517887] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[   20.519091] Call Trace:
[   20.519591]  show_stack+0x62/0x68
[   20.520156]  dump_stack+0x20/0x22
[   20.520720]  panic+0x22f/0x4f7
[   20.521264]  ? printk+0x48/0x4a
[   20.521814]  ? preempt_count_sub+0x147/0x1c4
[   20.522455]  mount_block_root+0x3a3/0x3b2
[   20.523070]  mount_root+0x7a/0x7d
[   20.523632]  prepare_namespace+0x199/0x1ca
[   20.524252]  kernel_init_freeable+0x2a0/0x2b8
[   20.524893]  ? rest_init+0x115/0x115
[   20.525475]  kernel_init+0xf/0x188
[   20.526049]  ? rest_init+0x115/0x115
[   20.526634]  ret_from_fork+0x22/0x30
[   20.527229] Kernel Offset: disabled



To reproduce:

        # build kernel
	cd linux
	cp config-5.9.0-rc3-00224-g7b81ce7cdcef3 .config
	make HOSTCC=gcc-9 CC=gcc-9 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email



Thanks,
Rong Chen