Path passed to ffs_mount() is garbage?

Matthew Dillon dillon at
Wed Mar 21 21:45:17 PDT 2007

:So I take my first foray into the dragonfly kernel and do this to
:ffs_mount() in /usr/src/sys/vfs/ufs/ffs_vfsops.c: I merely add a
: kprintf("ffs_mount to %s\n",((path == NULL) ? "(NULL)" : path));
:as the very first line of code (past the declarations of course).
:When I test this by starting up my vkernel, if path is non-null, it
:points to garbage data. 
:I'm probably being naive here, what am I missing?
:Dave Hayes - Consultant - Altadena CA, USA - dave at 
:>>> The opinions expressed above are entirely my own <<<

    path is passed from userland.  Its a userland pointer.  It shouldn't
    be garbage, but you probably need to do a copyin() into a kernel
    buffer instead of printing it directly.  Actually, I'm a little at 
    a loss because on the PC architecture the pointer should still be
    printable (if a bit dangerous due to being a userland address).

					Matthew Dillon 
					<dillon at>

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