Re: linux-next: Tree for Jan 20 -- Kernel panic - Unable to mount root fs

2015-01-20, 23:17:25 +0000, Al Viro wrote: > On Tue, Jan 20, 2015 at 10:50:41PM +0000, Al Viro wrote: > > doesn't look at _anything_ other than name->name other than for > > audit_inode(). And name->name is apparently the same. > > > > It looks like something ends up buggering name->name in process, but > > then > > the damn thing appears to be normal after return from > > filename_lookup()... > > If my reconstruction of what's going on is correct, the call chain here > is do_path_lookup() <- kern_path() <- lookup_bdev() <- > blkdev_get_by_path() > <- mount_bdev() <- some_type.mount() <- mount_fs() > <- vfs_kern_mount() <- do_new_mount() <- do_mount() <- sys_mount() > <- do_mount_root() <- mount_block_root() <- mount_root(). Which is > obscenely long, BTW, but that's a separate story... > > Could you slap > > struct stat buf; > int n = sys_newstat(name, &buf); > printk(KERN_ERR "stat(\"%s\") -> %d\n", name, n); > n = sys_newstat("/dev", &buf); > printk(KERN_ERR "stat(\"dev\") -> %d\n", n); > > in the beginning of mount_block_root() (init/do_mounts.c) and see what it > prints? I get stat("/dev/root") -> -2 stat("dev") -> -2 with the patch applied (+panic) and: stat("/dev/root") -> 0 stat("dev") -> 0 with the old version of do_path_lookup.