Jann Horn e3e4d5019c x86/kprobes: Stop calling fixup_exception() from kprobe_fault_handler() ... This removes the call into exception fixup that was added in commit c28f896634 ("[PATCH] kprobes: fix broken fault handling for x86_64"). On X86, kprobe_fault_handler() is called from two places: do_general_protection() (for #GP) and kprobes_fault() (for #PF). In both paths, the fixup_exception() call in the kprobe fault handler is redundant. In case of #GP, fixup_exception() is called immediately before kprobe_fault_handler() is invoked, so no need to try that again. This assumes that the kprobe's fault handler isn't going to do something crazy like changing RIP so that it suddenly points to an instruction that does userspace access. For #PF on a kernel address from kernel space, after the kprobe fault handler has run, no_context() is invoked, which calls fixup_exception(). Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Kees Cook <keescook@chromium.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: kernel-hardening@lists.openwall.com Cc: linux-kernel@vger.kernel.org Cc: dvyukov@google.com Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Cc: Borislav Petkov <bp@alien8.de> Link: https://lkml.kernel.org/r/20180828201421.157735-4-jannh@google.com		2018-09-03 15:12:08 +02:00
..
common.h	kprobes/x86: Don't call the ->break_handler() in x86 kprobes	2018-06-21 12:33:13 +02:00
core.c	x86/kprobes: Stop calling fixup_exception() from kprobe_fault_handler()	2018-09-03 15:12:08 +02:00
ftrace.c	bpf/error-inject/kprobes: Clear current_kprobe and enable preempt in kprobe	2018-06-21 12:33:19 +02:00
Makefile
opt.c	kprobes/x86: Do not disable preempt on int3 path	2018-06-21 12:33:20 +02:00