From: tip-bot for Masami Hiramatsu <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org,
andi@firstfloor.org, sandeepa.prabhu@linaro.org,
ananth@in.ibm.com, masami.hiramatsu.pt@hitachi.com,
fweisbec@gmail.com, rostedt@goodmis.org, tglx@linutronix.de
Subject: [tip:perf/urgent] kprobes/x86: Fix page-fault handling logic
Date: Thu, 17 Apr 2014 02:58:07 -0700 [thread overview]
Message-ID: <tip-6381c24cd6d5d6373620426ab0a96c80ed953e20@git.kernel.org> (raw)
In-Reply-To: <20140417081644.26341.52351.stgit@ltc230.yrl.intra.hitachi.co.jp>
Commit-ID: 6381c24cd6d5d6373620426ab0a96c80ed953e20
Gitweb: http://git.kernel.org/tip/6381c24cd6d5d6373620426ab0a96c80ed953e20
Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 17 Apr 2014 17:16:44 +0900
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 17 Apr 2014 10:57:02 +0200
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>
---
arch/x86/kernel/kprobes/core.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 79a3f96..61b17dc 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -897,9 +897,10 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- switch (kcb->kprobe_status) {
- case KPROBE_HIT_SS:
- case KPROBE_REENTER:
+ if (unlikely(regs->ip == (unsigned long)cur->ainsn.insn)) {
+ /* This must happen on single-stepping */
+ WARN_ON(kcb->kprobe_status != KPROBE_HIT_SS &&
+ kcb->kprobe_status != KPROBE_REENTER);
/*
* We are here because the instruction being single
* stepped caused a page fault. We reset the current
@@ -914,9 +915,8 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
else
reset_current_kprobe();
preempt_enable_no_resched();
- break;
- case KPROBE_HIT_ACTIVE:
- case KPROBE_HIT_SSDONE:
+ } else if (kcb->kprobe_status == KPROBE_HIT_ACTIVE ||
+ kcb->kprobe_status == KPROBE_HIT_SSDONE) {
/*
* We increment the nmissed count for accounting,
* we can also use npre/npostfault count for accounting
@@ -945,10 +945,8 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
* fixup routine could not handle it,
* Let do_page_fault() fix it.
*/
- break;
- default:
- break;
}
+
return 0;
}
next prev parent reply other threads:[~2014-04-17 9:58 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-17 8:16 [PATCH -tip v9 00/26] kprobes: introduce NOKPROBE_SYMBOL, bugfixes and scalbility efforts Masami Hiramatsu
2014-04-17 8:16 ` [PATCH -tip v9 01/26] [BUGFIX]kprobes/x86: Fix page-fault handling logic Masami Hiramatsu
2014-04-17 9:58 ` tip-bot for Masami Hiramatsu [this message]
2014-04-17 8:16 ` [PATCH -tip v9 02/26] kprobes/x86: Allow to handle reentered kprobe on singlestepping Masami Hiramatsu
2014-04-24 10:57 ` [tip:perf/kprobes] kprobes/x86: Allow to handle reentered kprobe on single-stepping tip-bot for Masami Hiramatsu
2014-04-17 8:16 ` [PATCH -tip v9 03/26] kprobes: Prohibit probing on .entry.text code Masami Hiramatsu
2014-04-24 10:57 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 04/26] kprobes: Introduce NOKPROBE_SYMBOL() macro for blacklist Masami Hiramatsu
2014-04-24 10:58 ` [tip:perf/kprobes] kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist tip-bot for Masami Hiramatsu
2014-05-01 5:26 ` kprobes broken in linux-next (was Re: [tip:perf/kprobes] kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist) Vineet Gupta
2014-05-02 1:13 ` Masami Hiramatsu
2014-05-07 4:56 ` Vineet Gupta
2014-05-07 19:18 ` [tip:perf/kprobes] kprobes: Ensure blacklist data is aligned tip-bot for Vineet Gupta
2014-05-05 20:48 ` [tip:perf/kprobes] kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist Tony Luck
2014-05-06 9:25 ` Masami Hiramatsu
2014-05-06 10:03 ` Masami Hiramatsu
2014-05-07 11:19 ` Masami Hiramatsu
2014-05-07 11:55 ` [RFT PATCH -next ] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64 Masami Hiramatsu
2014-05-07 11:59 ` Masami Hiramatsu
2014-05-14 8:19 ` Masami Hiramatsu
2014-05-08 4:47 ` Ananth N Mavinakayanahalli
2014-05-08 5:40 ` Masami Hiramatsu
2014-05-08 6:16 ` Ananth N Mavinakayanahalli
2014-05-09 8:06 ` Masami Hiramatsu
2014-05-26 11:25 ` Suzuki K. Poulose
2014-05-26 11:48 ` Masami Hiramatsu
2014-05-27 6:31 ` [RFT PATCH -next v2] " Masami Hiramatsu
2014-05-29 19:13 ` Suzuki K. Poulose
2014-05-30 2:47 ` Masami Hiramatsu
2014-05-30 3:18 ` [RFT PATCH -next v3] " Masami Hiramatsu
2014-06-06 6:38 ` Masami Hiramatsu
2014-06-17 23:03 ` Tony Luck
2014-06-18 7:56 ` Michael Ellerman
2014-06-18 8:46 ` Masami Hiramatsu
2014-06-19 1:30 ` Michael Ellerman
2014-06-19 4:52 ` Masami Hiramatsu
2014-06-19 6:40 ` Suzuki K. Poulose
2014-06-19 7:26 ` Masami Hiramatsu
2014-06-19 9:45 ` Suzuki K. Poulose
2014-06-19 11:01 ` Masami Hiramatsu
2014-06-19 11:20 ` Masami Hiramatsu
2014-06-20 0:37 ` Michael Ellerman
2014-06-20 2:13 ` Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 05/26] [BUGFIX] kprobes/x86: Prohibit probing on debug_stack_* Masami Hiramatsu
2014-04-24 10:58 ` [tip:perf/kprobes] kprobes, x86: Prohibit probing on debug_stack_*() tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 06/26] [BUGFIX] x86: Prohibit probing on native_set_debugreg/load_idt Masami Hiramatsu
2014-04-24 10:58 ` [tip:perf/kprobes] kprobes, x86: Prohibit probing on native_set_debugreg()/load_idt() tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 07/26] [BUGFIX] x86: Prohibit probing on thunk functions and restore Masami Hiramatsu
2014-04-24 10:58 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 08/26] kprobes/x86: Call exception handlers directly from do_int3/do_debug Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-24 11:26 ` Jiri Kosina
2014-04-17 8:17 ` [PATCH -tip v9 09/26] x86: Call exception_enter after kprobes handled Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-06-13 17:14 ` Frederic Weisbecker
2014-06-14 5:44 ` Masami Hiramatsu
2014-06-14 6:47 ` [PATCH -tip ] [Bugfix] x86/kprobes: Fix build errors and blacklist context_track_user Masami Hiramatsu
2014-06-14 8:58 ` [tip:perf/urgent] " tip-bot for Masami Hiramatsu
2014-06-16 15:52 ` [PATCH -tip ] [Bugfix] " Frederic Weisbecker
2014-04-17 8:17 ` [PATCH -tip v9 10/26] kprobes/x86: Allow probe on some kprobe preparation functions Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 11/26] kprobes: Allow probe on some kprobe functions Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 12/26] ftrace/*probes: Allow probing on some functions Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] kprobes, ftrace: " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 13/26] x86: Allow kprobes on text_poke/hw_breakpoint Masami Hiramatsu
2014-04-24 11:00 ` [tip:perf/kprobes] kprobes, x86: Allow kprobes on text_poke/ hw_breakpoint tip-bot for Masami Hiramatsu
2014-04-24 11:26 ` Jiri Kosina
2014-04-17 8:18 ` [PATCH -tip v9 14/26] x86: Use NOKPROBE_SYMBOL() instead of __kprobes annotation Masami Hiramatsu
2014-04-24 11:00 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 15/26] kprobes: Use NOKPROBE_SYMBOL macro instead of __kprobes Masami Hiramatsu
2014-04-24 11:00 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 16/26] ftrace/kprobes: Use NOKPROBE_SYMBOL macro in ftrace Masami Hiramatsu
2014-04-24 11:00 ` [tip:perf/kprobes] kprobes, ftrace: " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 17/26] notifier: Use NOKPROBE_SYMBOL macro in notifier Masami Hiramatsu
2014-04-17 14:40 ` Josh Triplett
2014-04-24 11:00 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 18/26] sched: Use NOKPROBE_SYMBOL macro in sched Masami Hiramatsu
2014-04-24 11:01 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 19/26] kprobes: Show blacklist entries via debugfs Masami Hiramatsu
2014-04-24 11:01 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 20/26] kprobes: Support blacklist functions in module Masami Hiramatsu
2014-04-24 8:56 ` Ingo Molnar
2014-04-24 11:24 ` Masami Hiramatsu
2014-04-25 8:19 ` Ingo Molnar
2014-04-25 10:12 ` Masami Hiramatsu
2014-04-25 10:55 ` Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 21/26] kprobes: Use NOKPROBE_SYMBOL() in sample modules Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 22/26] kprobes/x86: Use kprobe_blacklist for .kprobes.text and .entry.text Masami Hiramatsu
2014-04-24 8:58 ` Ingo Molnar
2014-04-24 11:22 ` Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 23/26] kprobes/x86: Remove unneeded preempt_disable/enable in interrupt handlers Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 24/26] kprobes: Enlarge hash table to 512 entries Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 25/26] kprobes: Introduce kprobe cache to reduce cache misshits Masami Hiramatsu
2014-04-24 9:01 ` Ingo Molnar
2014-04-24 11:38 ` Masami Hiramatsu
2014-04-25 8:20 ` Ingo Molnar
2014-04-25 9:43 ` Masami Hiramatsu
2014-04-26 7:12 ` Ingo Molnar
2014-04-27 12:49 ` Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 26/26] ftrace: Introduce FTRACE_OPS_FL_SELF_FILTER for ftrace-kprobe Masami Hiramatsu
2014-04-17 8:37 ` [PATCH -tip v9 00/26] kprobes: introduce NOKPROBE_SYMBOL, bugfixes and scalbility efforts Ingo Molnar
2014-04-17 8:53 ` Masami Hiramatsu
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