There is no need to go through handle_page_fault(). If we try to access the zero page in kernel mode just panic().
Signed-off-by: Richard Weinberger <[email protected]> --- arch/um/kernel/trap.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index 974b874..b0a3017 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -218,10 +218,15 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, panic("Segfault with no mm"); } - if (SEGV_IS_FIXABLE(&fi) || SEGV_MAYBE_FIXABLE(&fi)) + if (SEGV_IS_FIXABLE(&fi) || SEGV_MAYBE_FIXABLE(&fi)) { + if (!is_user && address < PAGE_SIZE) { + show_regs(container_of(regs, struct pt_regs, regs)); + panic("NULL pointer dereference at ip:0x%lx address:0x%lx", ip, address); + } + err = handle_page_fault(address, ip, is_write, is_user, &si.si_code); - else { + } else { err = -EFAULT; /* * A thread accessed NULL, we get a fault, but CR2 is invalid. -- 1.8.4.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
