Masami Hiramatsu 6381c24cd6 kprobes/x86: Fix page-fault handling logic ... Current kprobes in-kernel page fault handler doesn't expect that its single-stepping can be interrupted by an NMI handler which may cause a page fault(e.g. perf with callback tracing). In that case, the page-fault handled by kprobes and it misunderstands the page-fault has been caused by the single-stepping code and tries to recover IP address to probed address. But the truth is the page-fault has been caused by the NMI handler, and do_page_fault failes to handle real page fault because the IP address is modified and causes Kernel BUGs like below. ---- [ 2264.726905] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 [ 2264.727190] IP: [<ffffffff813c46e0>] copy_user_generic_string+0x0/0x40 To handle this correctly, I fixed the kprobes fault handler to ensure the faulted ip address is its own single-step buffer instead of checking current kprobe state. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Sandeepa Prabhu <sandeepa.prabhu@linaro.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: fche@redhat.com Cc: systemtap@sourceware.org Link: http://lkml.kernel.org/r/20140417081644.26341.52351.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar <mingo@kernel.org>		2014-04-17 10:57:02 +02:00
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common.h	kprobes/x86: Use text_poke_bp() instead of text_poke_smp*()	2013-07-19 09:57:04 +02:00
core.c	kprobes/x86: Fix page-fault handling logic	2014-04-17 10:57:02 +02:00
ftrace.c	kprobes/x86: Move kprobes stuff under arch/x86/kernel/kprobes/	2013-01-21 13:22:37 -05:00
Makefile	kprobes/x86: Move kprobes stuff under arch/x86/kernel/kprobes/	2013-01-21 13:22:37 -05:00
opt.c	Merge branch 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-09-04 08:42:44 -07:00