From: rostedt at goodmis.org (Steven Rostedt) Subject: [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions Date: Thu, 2 May 2019 19:50:52 -0400 [thread overview] Message-ID: <20190502195052.0af473cf@gandalf.local.home> (raw) In-Reply-To: <20190502193129.664c5b2e@gandalf.local.home> On Thu, 2 May 2019 19:31:29 -0400 Steven Rostedt <rostedt at goodmis.org> wrote: > Digging a little further, I pinpointed it out to being kretprobes. The > problem I believe is the use of kernel_stack_pointer() which does some > magic on x86_32. kretprobes uses this to hijack the return address of > the function (much like the function graph tracer does). I do have code > that would allow kretprobes to use the function graph tracer instead, > but that's still in progress (almost done!). But still, we should not > have this break the use of kernel_stack_pointer() either. > > Adding some printks in that code, it looks to be returning "®s->sp" > which I think we changed. > This appears to fix it! -- Steve diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 4b8ee05dd6ad..600ead178bf4 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -171,8 +171,12 @@ unsigned long kernel_stack_pointer(struct pt_regs *regs) unsigned long sp = (unsigned long)®s->sp; u32 *prev_esp; - if (context == (sp & ~(THREAD_SIZE - 1))) + if (context == (sp & ~(THREAD_SIZE - 1))) { + /* int3 code adds a gap */ + if (sp == regs->sp - 5*4) + return regs->sp; return sp; + } prev_esp = (u32 *)(context); if (*prev_esp)
WARNING: multiple messages have this Message-ID (diff)
From: rostedt@goodmis.org (Steven Rostedt) Subject: [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions Date: Thu, 2 May 2019 19:50:52 -0400 [thread overview] Message-ID: <20190502195052.0af473cf@gandalf.local.home> (raw) Message-ID: <20190502235052.BVHK6H_1YuEbOfQlLNBPsdZsw3nDqvP1r_ysWwR6ncA@z> (raw) In-Reply-To: <20190502193129.664c5b2e@gandalf.local.home> On Thu, 2 May 2019 19:31:29 -0400 Steven Rostedt <rostedt@goodmis.org> wrote: > Digging a little further, I pinpointed it out to being kretprobes. The > problem I believe is the use of kernel_stack_pointer() which does some > magic on x86_32. kretprobes uses this to hijack the return address of > the function (much like the function graph tracer does). I do have code > that would allow kretprobes to use the function graph tracer instead, > but that's still in progress (almost done!). But still, we should not > have this break the use of kernel_stack_pointer() either. > > Adding some printks in that code, it looks to be returning "®s->sp" > which I think we changed. > This appears to fix it! -- Steve diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 4b8ee05dd6ad..600ead178bf4 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -171,8 +171,12 @@ unsigned long kernel_stack_pointer(struct pt_regs *regs) unsigned long sp = (unsigned long)®s->sp; u32 *prev_esp; - if (context == (sp & ~(THREAD_SIZE - 1))) + if (context == (sp & ~(THREAD_SIZE - 1))) { + /* int3 code adds a gap */ + if (sp == regs->sp - 5*4) + return regs->sp; return sp; + } prev_esp = (u32 *)(context); if (*prev_esp)
next prev parent reply other threads:[~2019-05-02 23:50 UTC|newest] Thread overview: 204+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <20190501202830.347656894@goodmis.org> 2019-05-01 20:28 ` [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions rostedt 2019-05-01 20:28 ` Steven Rostedt 2019-05-02 3:24 ` rostedt 2019-05-02 3:24 ` Steven Rostedt 2019-05-02 16:21 ` peterz 2019-05-02 16:21 ` Peter Zijlstra 2019-05-02 16:29 ` peterz 2019-05-02 16:29 ` Peter Zijlstra 2019-05-02 18:02 ` torvalds 2019-05-02 18:02 ` Linus Torvalds 2019-05-02 18:18 ` peterz 2019-05-02 18:18 ` Peter Zijlstra 2019-05-02 18:30 ` peterz 2019-05-02 18:30 ` Peter Zijlstra 2019-05-02 18:43 ` torvalds 2019-05-02 18:43 ` Linus Torvalds 2019-05-02 19:28 ` jikos 2019-05-02 19:28 ` Jiri Kosina 2019-05-02 20:25 ` luto 2019-05-02 20:25 ` Andy Lutomirski 2019-05-02 20:21 ` peterz 2019-05-02 20:21 ` Peter Zijlstra 2019-05-02 20:49 ` torvalds 2019-05-02 20:49 ` Linus Torvalds 2019-05-02 21:32 ` peterz 2019-05-02 21:32 ` Peter Zijlstra 2019-05-03 19:24 ` rostedt 2019-05-03 19:24 ` Steven Rostedt 2019-05-03 21:46 ` torvalds 2019-05-03 21:46 ` Linus Torvalds 2019-05-03 22:49 ` rostedt 2019-05-03 22:49 ` Steven Rostedt 2019-05-03 23:07 ` torvalds 2019-05-03 23:07 ` Linus Torvalds 2019-05-04 4:17 ` rostedt 2019-05-04 4:17 ` Steven Rostedt [not found] ` <CAHk-=wiuSFbv_rELND-BLWcP0GSZ0yF=xOAEcf61GE3bU9d=yg@mail.gmail.com> 2019-05-04 18:59 ` torvalds 2019-05-04 18:59 ` Linus Torvalds 2019-05-04 20:12 ` luto 2019-05-04 20:12 ` Andy Lutomirski 2019-05-04 20:28 ` torvalds 2019-05-04 20:28 ` Linus Torvalds 2019-05-04 20:36 ` torvalds 2019-05-04 20:36 ` Linus Torvalds 2019-05-03 22:55 ` luto 2019-05-03 22:55 ` Andy Lutomirski 2019-05-03 23:16 ` torvalds 2019-05-03 23:16 ` Linus Torvalds 2019-05-03 23:32 ` luto 2019-05-03 23:32 ` Andy Lutomirski 2019-05-02 22:52 ` rostedt 2019-05-02 22:52 ` Steven Rostedt 2019-05-02 23:31 ` rostedt 2019-05-02 23:31 ` Steven Rostedt 2019-05-02 23:50 ` rostedt [this message] 2019-05-02 23:50 ` Steven Rostedt 2019-05-03 1:51 ` [RFC][PATCH 1/2 v2] " rostedt 2019-05-03 1:51 ` Steven Rostedt 2019-05-03 9:29 ` [RFC][PATCH 1/2] " peterz 2019-05-03 9:29 ` Peter Zijlstra 2019-05-03 13:22 ` rostedt 2019-05-03 13:22 ` Steven Rostedt 2019-05-03 16:20 ` luto 2019-05-03 16:20 ` Andy Lutomirski 2019-05-03 16:31 ` rostedt 2019-05-03 16:31 ` Steven Rostedt 2019-05-03 16:35 ` peterz 2019-05-03 16:35 ` Peter Zijlstra 2019-05-03 16:44 ` luto 2019-05-03 16:44 ` Andy Lutomirski 2019-05-03 16:49 ` rostedt 2019-05-03 16:49 ` Steven Rostedt 2019-05-03 16:32 ` peterz 2019-05-03 16:32 ` Peter Zijlstra 2019-05-03 18:57 ` torvalds 2019-05-03 18:57 ` Linus Torvalds 2019-05-06 8:19 ` peterz 2019-05-06 8:19 ` Peter Zijlstra 2019-05-06 13:56 ` rostedt 2019-05-06 13:56 ` Steven Rostedt 2019-05-06 16:17 ` torvalds 2019-05-06 16:17 ` Linus Torvalds 2019-05-06 16:19 ` torvalds 2019-05-06 16:19 ` Linus Torvalds 2019-05-06 17:06 ` rostedt 2019-05-06 17:06 ` Steven Rostedt 2019-05-06 18:06 ` torvalds 2019-05-06 18:06 ` Linus Torvalds 2019-05-06 18:57 ` rostedt 2019-05-06 18:57 ` Steven Rostedt 2019-05-06 19:46 ` torvalds 2019-05-06 19:46 ` Linus Torvalds 2019-05-06 20:29 ` rostedt 2019-05-06 20:29 ` Steven Rostedt 2019-05-06 20:42 ` torvalds 2019-05-06 20:42 ` Linus Torvalds 2019-05-06 20:44 ` torvalds 2019-05-06 20:44 ` Linus Torvalds 2019-05-06 21:45 ` rostedt 2019-05-06 21:45 ` Steven Rostedt 2019-05-06 22:06 ` torvalds 2019-05-06 22:06 ` Linus Torvalds 2019-05-06 22:31 ` torvalds 2019-05-06 22:31 ` Linus Torvalds 2019-05-07 0:10 ` rostedt 2019-05-07 0:10 ` Steven Rostedt 2019-05-07 1:06 ` torvalds 2019-05-07 1:06 ` Linus Torvalds 2019-05-07 1:04 ` rostedt 2019-05-07 1:04 ` Steven Rostedt 2019-05-07 1:34 ` rostedt 2019-05-07 1:34 ` Steven Rostedt 2019-05-07 1:34 ` torvalds 2019-05-07 1:34 ` Linus Torvalds 2019-05-07 1:53 ` rostedt 2019-05-07 1:53 ` Steven Rostedt 2019-05-07 2:22 ` torvalds 2019-05-07 2:22 ` Linus Torvalds 2019-05-07 2:58 ` rostedt 2019-05-07 2:58 ` Steven Rostedt 2019-05-07 3:05 ` torvalds 2019-05-07 3:05 ` Linus Torvalds 2019-05-07 3:21 ` rostedt 2019-05-07 3:21 ` Steven Rostedt 2019-05-07 3:28 ` torvalds 2019-05-07 3:28 ` Linus Torvalds 2019-05-07 14:54 ` torvalds 2019-05-07 14:54 ` Linus Torvalds 2019-05-07 15:12 ` rostedt 2019-05-07 15:12 ` Steven Rostedt 2019-05-07 15:25 ` rostedt 2019-05-07 15:25 ` Steven Rostedt 2019-05-07 16:25 ` rostedt 2019-05-07 16:25 ` Steven Rostedt 2019-05-07 15:31 ` torvalds 2019-05-07 15:31 ` Linus Torvalds 2019-05-07 15:45 ` rostedt 2019-05-07 15:45 ` Steven Rostedt 2019-05-07 16:34 ` peterz 2019-05-07 16:34 ` Peter Zijlstra 2019-05-07 17:08 ` torvalds 2019-05-07 17:08 ` Linus Torvalds 2019-05-07 17:21 ` jpoimboe 2019-05-07 17:21 ` Josh Poimboeuf 2019-05-07 21:24 ` rostedt 2019-05-07 21:24 ` Steven Rostedt 2019-05-08 4:50 ` torvalds 2019-05-08 4:50 ` Linus Torvalds 2019-05-08 16:37 ` rostedt 2019-05-08 16:37 ` Steven Rostedt 2019-05-07 17:38 ` peterz 2019-05-07 17:38 ` Peter Zijlstra 2019-05-07 9:51 ` peterz 2019-05-07 9:51 ` Peter Zijlstra 2019-05-07 14:48 ` luto 2019-05-07 14:48 ` Andy Lutomirski 2019-05-07 14:57 ` torvalds 2019-05-07 14:57 ` Linus Torvalds 2019-05-07 14:13 ` mhiramat 2019-05-07 14:13 ` Masami Hiramatsu 2019-05-07 17:15 ` mhiramat 2019-05-07 17:15 ` Masami Hiramatsu 2019-05-06 14:22 ` peterz 2019-05-06 14:22 ` Peter Zijlstra 2019-05-07 8:57 ` peterz 2019-05-07 8:57 ` Peter Zijlstra 2019-05-07 9:18 ` David.Laight 2019-05-07 9:18 ` David Laight 2019-05-07 11:30 ` peterz 2019-05-07 11:30 ` Peter Zijlstra 2019-05-07 12:57 ` David.Laight 2019-05-07 12:57 ` David Laight 2019-05-07 13:14 ` rostedt 2019-05-07 13:14 ` Steven Rostedt 2019-05-07 14:50 ` David.Laight 2019-05-07 14:50 ` David Laight 2019-05-07 14:57 ` rostedt 2019-05-07 14:57 ` Steven Rostedt 2019-05-07 15:46 ` David.Laight 2019-05-07 15:46 ` David Laight 2019-05-07 13:32 ` peterz 2019-05-07 13:32 ` Peter Zijlstra 2019-05-07 9:27 ` peterz 2019-05-07 9:27 ` Peter Zijlstra 2019-05-07 12:27 ` rostedt 2019-05-07 12:27 ` Steven Rostedt 2019-05-07 12:41 ` peterz 2019-05-07 12:41 ` Peter Zijlstra 2019-05-07 12:54 ` rostedt 2019-05-07 12:54 ` Steven Rostedt 2019-05-07 17:22 ` masami.hiramatsu 2019-05-07 17:22 ` Masami Hiramatsu 2019-05-07 14:28 ` peterz 2019-05-07 14:28 ` Peter Zijlstra 2019-05-02 20:48 ` rostedt 2019-05-02 20:48 ` Steven Rostedt 2019-05-06 15:14 ` jpoimboe 2019-05-06 15:14 ` Josh Poimboeuf 2019-05-01 20:28 ` [RFC][PATCH 2/2] ftrace/x86: Emulate call function while updating in breakpoint handler rostedt 2019-05-01 20:28 ` Steven Rostedt 2019-05-03 10:22 ` [RFC][PATCH 1.5/2] x86: Add int3_emulate_call() selftest peterz 2019-05-03 10:22 ` Peter Zijlstra 2019-05-03 18:46 ` rostedt 2019-05-03 18:46 ` Steven Rostedt
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