On 9 January 2015 at 18:25, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote: > "Michael Kerrisk (man-pages)" <mtk.manpages@xxxxxxxxx> writes: > >> From: Michael Kerrisk <mtk.manpages@xxxxxxxxx> >> >> commit fe8c7f5cbf91124987106faa3bdf0c8b955c4cf7 added two new prctl() >> operations, PR_MPX_ENABLE_MANAGEMENT and PR_MPX_DISABLE_MANAGEMENT. >> However, no checks were included to ensure that unused arguments >> are zero, as is done in many existing prctl()s and as should be >> done for all new prctl()s. This patch adds the required checks. > > This will break the existing gcc run time, which doesn't zero these > arguments. I'm a little lost here. Weren't these flags new in the as-yet-unreleased 3.19? How does gcc run-time depends on them already? Thanks, Michael >> Signed-off-by: Michael Kerrisk <mtk.manpages@xxxxxxxxx> >> --- >> kernel/sys.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/kernel/sys.c b/kernel/sys.c >> index a8c9f5a..ea9c881 100644 >> --- a/kernel/sys.c >> +++ b/kernel/sys.c >> @@ -2210,9 +2210,13 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, >> up_write(&me->mm->mmap_sem); >> break; >> case PR_MPX_ENABLE_MANAGEMENT: >> + if (arg2 || arg3 || arg4 || arg5) >> + return -EINVAL; >> error = MPX_ENABLE_MANAGEMENT(me); >> break; >> case PR_MPX_DISABLE_MANAGEMENT: >> + if (arg2 || arg3 || arg4 || arg5) >> + return -EINVAL; >> error = MPX_DISABLE_MANAGEMENT(me); >> break; >> default: >> -- >> 1.9.3 > > -- > ak@xxxxxxxxxxxxxxx -- Speaking for myself only -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>