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authorMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>2014-04-17 12:17:33 +0400
committerIngo Molnar <mingo@kernel.org>2014-04-24 12:02:59 +0400
commit6f6343f53d133bae516caf3d254bce37d8774625 (patch)
tree78beecd00443bd166982c3de9c44a624b7196c7f /arch/x86/include/asm/kprobes.h
parent98def1dedd00f42ded8423c418c971751f46aad2 (diff)
downloadlinux-6f6343f53d133bae516caf3d254bce37d8774625.tar.xz
kprobes/x86: Call exception handlers directly from do_int3/do_debug
To avoid a kernel crash by probing on lockdep code, call kprobe_int3_handler() and kprobe_debug_handler()(which was formerly called post_kprobe_handler()) directly from do_int3 and do_debug. Currently kprobes uses notify_die() to hook the int3/debug exceptoins. Since there is a locking code in notify_die, the lockdep code can be invoked. And because the lockdep involves printk() related things, theoretically, we need to prohibit probing on such code, which means much longer blacklist we'll have. Instead, hooking the int3/debug for kprobes before notify_die() can avoid this problem. Anyway, most of the int3 handlers in the kernel are already called from do_int3 directly, e.g. ftrace_int3_handler, poke_int3_handler, kgdb_ll_trap. Actually only kprobe_exceptions_notify is on the notifier_call_chain. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@suse.de> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Jonathan Lebon <jlebon@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Link: http://lkml.kernel.org/r/20140417081733.26341.24423.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/kprobes.h')
-rw-r--r--arch/x86/include/asm/kprobes.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h
index 9454c167629f..53cdfb2857ab 100644
--- a/arch/x86/include/asm/kprobes.h
+++ b/arch/x86/include/asm/kprobes.h
@@ -116,4 +116,6 @@ struct kprobe_ctlblk {
extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
extern int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data);
+extern int kprobe_int3_handler(struct pt_regs *regs);
+extern int kprobe_debug_handler(struct pt_regs *regs);
#endif /* _ASM_X86_KPROBES_H */