3c681ec96d
commit 913050b91eb94f194392dd797b1ff3779f606ac0 upstream. If oprofilefs_ulong_from_user() is called with count equals zero, *val remains unchanged. Depending on the implementation it might be uninitialized. Change oprofilefs_ulong_from_user()'s interface to return count on success. Thus, we are able to return early if count equals zero which avoids using *val uninitialized. Fixing all users of oprofilefs_ulong_ from_user(). This follows write syscall implementation when count is zero: "If count is zero ... [and if] no errors are detected, 0 will be returned without causing any other effect." (man 2 write) Reported-By: Mike Waychison <mikew@google.com> Signed-off-by: Robert Richter <robert.richter@amd.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: oprofile-list <oprofile-list@lists.sourceforge.net> Link: http://lkml.kernel.org/r/20111219153830.GH16765@erda.amd.com Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>