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X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Sep 2021 06:38:24.7479 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: c68c4c26-7fd5-4441-0175-08d97b3814ef X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.112.34];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BN8NAM11FT051.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN6PR12MB4765 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 19, 2021 at 06:08:44AM +0000, Al Viro wrote: > On Sun, Sep 19, 2021 at 08:46:39AM +0300, Leon Romanovsky wrote: > > On Tue, Sep 14, 2021 at 12:12:10PM +0300, Leon Romanovsky wrote: > > > From: Leon Romanovsky > > > > > > Attempt to mount 9p file system as root gives the following kernel panic: > > > > > > 9pnet_virtio: no channels available for device root > > > Kernel panic - not syncing: VFS: Unable to mount root "root" (9p), err=-2 > > > CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.15.0-rc1+ #127 > > > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 > > > Call Trace: > > > dump_stack_lvl+0x45/0x59 > > > panic+0x1e2/0x44b > > > ? __warn_printk+0xf3/0xf3 > > > ? free_unref_page+0x2d4/0x4a0 > > > ? trace_hardirqs_on+0x32/0x120 > > > ? free_unref_page+0x2d4/0x4a0 > > > mount_root+0x189/0x1e0 > > > prepare_namespace+0x136/0x165 > > > kernel_init_freeable+0x3b8/0x3cb > > > ? rest_init+0x2e0/0x2e0 > > > kernel_init+0x19/0x130 > > > ret_from_fork+0x1f/0x30 > > > Kernel Offset: disabled > > > ---[ end Kernel panic - not syncing: VFS: Unable to mount root "root" (9p), err=-2 ]--- > > > > > > QEMU command line: > > > "qemu-system-x86_64 -append root=/dev/root rw rootfstype=9p rootflags=trans=virtio ..." > > > > > > This error is because root_device_name is truncated in prepare_namespace() from > > > being "/dev/root" to be "root" prior to call to mount_nodev_root(). > > > > > > As a solution, don't treat errors in mount_nodev_root() as errors that > > > require panics and allow failback to the mount flow that existed before > > > patch citied in Fixes tag. > > > > > > Fixes: f9259be6a9e7 ("init: allow mounting arbitrary non-blockdevice filesystems as root") > > > Signed-off-by: Leon Romanovsky > > > --- > > > I'm not sure if this is the right thing to do, but it works for me. > > > --- > > > init/do_mounts.c | 3 --- > > > 1 file changed, 3 deletions(-) > > > > Hi, > > > > I assume that after Christoph gave his ROB [1], the patch is ok. > > Should I do anything else in order to progress with merging it? > > Sits in the local pile; will go to Linus tomorrow... Thanks Al, I have a question for the next time, is it possible to see the status of the patches without nagging you? Thanks