diff options
| author | Jann Horn <jannh@google.com> | 2018-08-28 22:14:15 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-09-03 15:12:08 +0200 |
| commit | a980c0ef9f6d8c45445d6ed0f5836bb6941c8c91 (patch) | |
| tree | ccbf6e3ce1f59ad02f6b8744e51b3a4c74e4523f /arch | |
| parent | 60c1f89241d49bacf71035470684a8d7b4bb46ea (diff) | |
x86/kprobes: Refactor kprobes_fault() like kprobe_exceptions_notify()
This is an extension of commit b506a9d08bae ("x86: code clarification patch
to Kprobes arch code"). As that commit explains, even though
kprobe_running() can't be called with preemption enabled, preemption does
not need to be disabled. If preemption is enabled, then this can't be
originate from a kprobe.
Also, use X86_TRAP_PF instead of 14.
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: 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/20180828201421.157735-2-jannh@google.com
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/mm/fault.c | 24 |
1 files changed, 13 insertions, 11 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 47bebfe6efa7..d99edb2d567b 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -44,17 +44,19 @@ kmmio_fault(struct pt_regs *regs, unsigned long addr) static nokprobe_inline int kprobes_fault(struct pt_regs *regs) { - int ret = 0; - - /* kprobe_running() needs smp_processor_id() */ - if (kprobes_built_in() && !user_mode(regs)) { - preempt_disable(); - if (kprobe_running() && kprobe_fault_handler(regs, 14)) - ret = 1; - preempt_enable(); - } - - return ret; + if (!kprobes_built_in()) + return 0; + if (user_mode(regs)) + return 0; + /* + * To be potentially processing a kprobe fault and to be allowed to call + * kprobe_running(), we have to be non-preemptible. + */ + if (preemptible()) + return 0; + if (!kprobe_running()) + return 0; + return kprobe_fault_handler(regs, X86_TRAP_PF); } /* |