]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
x86: apm: avoid uninitialized data
authorArnd Bergmann <arnd@arndb.de>
Thu, 10 Nov 2016 16:44:46 +0000 (17:44 +0100)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 11 Nov 2016 16:45:08 +0000 (08:45 -0800)
commit3a6d867612dce2035ca50cb02e7871d27c86aa72
tree6babb572b78290f960434e47b6341ccec30dc05a
parente84efa32b9d2763fb92e73c8942100d8f55ad4ed
x86: apm: avoid uninitialized data

apm_bios_call() can fail, and return a status in its argument structure.
If that status however is zero during a call from
apm_get_power_status(), we end up using data that may have never been
set, as reported by "gcc -Wmaybe-uninitialized":

  arch/x86/kernel/apm_32.c: In function ‘apm’:
  arch/x86/kernel/apm_32.c:1729:17: error: ‘bx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  arch/x86/kernel/apm_32.c:1835:5: error: ‘cx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  arch/x86/kernel/apm_32.c:1730:17: note: ‘cx’ was declared here
  arch/x86/kernel/apm_32.c:1842:27: error: ‘dx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  arch/x86/kernel/apm_32.c:1731:17: note: ‘dx’ was declared here

This changes the function to return "APM_NO_ERROR" here, which makes the
code more robust to broken BIOS versions, and avoids the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/x86/kernel/apm_32.c