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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> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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| .. | ||
| Kconfig | ||
| Makefile | ||
| pps_parport.c | ||
| pps-gpio.c | ||
| pps-ktimer.c | ||
| pps-ldisc.c | ||