diff options
| author | Jiri Slaby <jslaby@suse.cz> | 2016-07-20 15:45:08 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-08-10 11:49:25 +0200 |
| commit | 78edebc495bbd8e3c2cced6a937467140a4fd52b (patch) | |
| tree | e90d4011e26f3aa0ef7bcb27e8cabee010d41c7b /drivers/pps | |
| parent | f2e7c1f79f13a6a073d98f4e69fe81aa230f2607 (diff) | |
pps: do not crash when failed to register
commit 368301f2fe4b07e5fb71dba3cc566bc59eb6705f upstream.
With this command sequence:
modprobe plip
modprobe pps_parport
rmmod pps_parport
the partport_pps modules causes this crash:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: parport_detach+0x1d/0x60 [pps_parport]
Oops: 0000 [#1] SMP
...
Call Trace:
parport_unregister_driver+0x65/0xc0 [parport]
SyS_delete_module+0x187/0x210
The sequence that builds up to this is:
1) plip is loaded and takes the parport device for exclusive use:
plip0: Parallel port at 0x378, using IRQ 7.
2) pps_parport then fails to grab the device:
pps_parport: parallel port PPS client
parport0: cannot grant exclusive access for device pps_parport
pps_parport: couldn't register with parport0
3) rmmod of pps_parport is then killed because it tries to access
pardev->name, but pardev (taken from port->cad) is NULL.
So add a check for NULL in the test there too.
Link: http://lkml.kernel.org/r/20160714115245.12651-1-jslaby@suse.cz
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/pps')
| -rw-r--r-- | drivers/pps/clients/pps_parport.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/pps/clients/pps_parport.c b/drivers/pps/clients/pps_parport.c index 38a8bbe74810..83797d89c30f 100644 --- a/drivers/pps/clients/pps_parport.c +++ b/drivers/pps/clients/pps_parport.c @@ -195,7 +195,7 @@ static void parport_detach(struct parport *port) struct pps_client_pp *device; /* FIXME: oooh, this is ugly! */ - if (strcmp(pardev->name, KBUILD_MODNAME)) + if (!pardev || strcmp(pardev->name, KBUILD_MODNAME)) /* not our port */ return; |