1. 10 Nov, 2008 1 commit
    • David Brownell's avatar
      gpiolib: fix oops in gpio_get_value_cansleep() · fa1b2846
      David Brownell authored
      commit 978ccaa8 upstream
      
      We can get the following oops from gpio_get_value_cansleep() when a GPIO
      controller doesn't provide a get() callback:
      
       Unable to handle kernel paging request for instruction fetch
       Faulting instruction address: 0x00000000
       Oops: Kernel access of bad area, sig: 11 [#1]
       [...]
       NIP [00000000] 0x0
       LR [c0182fb0] gpio_get_value_cansleep+0x40/0x50
       Call Trace:
       [c7b79e80] [c0183f28] gpio_value_show+0x5c/0x94
       [c7b79ea0] [c01a584c] dev_attr_show+0x30/0x7c
       [c7b79eb0] [c00d6b48] fill_read_buffer+0x68/0xe0
       [c7b79ed0] [c00d6c54] sysfs_read_file+0x94/0xbc
       [c7b79ef0] [c008f24c] vfs_read+0xb4/0x16c
       [c7b79f10] [c008f580] sys_read+0x4c/0x90
       [c7b79f40] [c0013a14] ret_from_syscall+0x0/0x38
      
      It's OK to request the value of *any* GPIO; most GPIOs are bidirectional,
      so configuring them as outputs just enables an output driver and doesn't
      disable the input logic.
      
      So the problem is that gpio_get_value_cansleep() isn't making the same
      sanity check that gpio_get_value() does: making sure this GPIO isn't one
      of the atypical "no input logic" cases.
      Reported-by: default avatarAnton Vorontsov <avorontsov@ru.mvista.com>
      Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      fa1b2846
  2. 22 Oct, 2008 28 commits
  3. 09 Oct, 2008 11 commits