From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>,
Linux-mm <linux-mm@kvack.org>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Hugh Dickins <hughd@google.com>,
Christoph Hellwig <hch@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andi Kleen <andi@firstfloor.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jim Keniston <jkenisto@linux.vnet.ibm.com>,
Roland McGrath <roland@hack.frob.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 13/X] uprobes: introduce UTASK_SSTEP_TRAPPED logic
Date: Mon, 24 Oct 2011 20:46:14 +0530 [thread overview]
Message-ID: <20111024151614.GA6034@in.ibm.com> (raw)
In-Reply-To: <20111024144127.GA14975@redhat.com>
On Mon, Oct 24, 2011 at 04:41:27PM +0200, Oleg Nesterov wrote:
> On 10/22, Ananth N Mavinakayanahalli wrote:
> >
> > On Wed, Oct 19, 2011 at 11:53:44PM +0200, Oleg Nesterov wrote:
> > > Finally, add UTASK_SSTEP_TRAPPED state/code to handle the case when
> > > xol insn itself triggers the signal.
> > >
> > > In this case we should restart the original insn even if the task is
> > > already SIGKILL'ed (say, the coredump should report the correct ip).
> > > This is even more important if the task has a handler for SIGSEGV/etc,
> > > The _same_ instruction should be repeated again after return from the
> > > signal handler, and SSTEP can never finish in this case.
> >
> > Oleg,
> >
> > Not sure I understand this completely...
>
> I hope you do not think I do ;)
I think you understand it better than you think you do :-)
> > When you say 'correct ip' you mean the original vaddr where we now have
> > a uprobe breakpoint and not the xol copy, right?
>
> Yes,
>
> > Coredump needs to report the correct ip, but should it also not report
> > correctly the instruction that caused the signal? Ergo, shouldn't we
> > put the original instruction back at the uprobed vaddr?
>
> OK, now I see what you mean. I was confused by the "restore the original
> instruction before _restart_" suggestion.
>
> Agreed! it would be nice to "hide" these int3's if we dump the core, but
> I think this is a bit off-topic. It makes sense to do this in any case,
> even if the core-dumping was triggered by another thread/insn. It makes
> sense to remove all int3's, not only at regs->ip location. But how can
> we do this? This is nontrivial.
I don't think that is a problem.. see below...
> And. Even worse. Suppose that you do "gdb probed_application". Now you
> see int3's in the disassemble output. What can we do?
In this case, nothing.
> I think we can do nothing, at least currently. This just reflects the
> fact that uprobe connects to inode, not to process/mm/etc.
>
> What do you think?
Thinking further on this, in the normal 'running gdb on a core' case, we
won't have this problem, as the binary that we point gdb to, will be a
pristine one, without the uprobe int3s, right?
Ananth
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next prev parent reply other threads:[~2011-10-24 15:18 UTC|newest]
Thread overview: 160+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-20 11:59 [PATCH v5 3.1.0-rc4-tip 0/26] Uprobes patchset with perf probe support Srikar Dronamraju
2011-09-20 11:59 ` [PATCH v5 3.1.0-rc4-tip 1/26] uprobes: Auxillary routines to insert, find, delete uprobes Srikar Dronamraju
2011-09-20 15:42 ` Stefan Hajnoczi
2011-09-26 11:18 ` Peter Zijlstra
2011-09-26 11:59 ` Srikar Dronamraju
2011-09-26 11:18 ` Peter Zijlstra
2011-09-26 12:02 ` Srikar Dronamraju
2011-09-26 13:35 ` Peter Zijlstra
2011-09-26 16:19 ` Srikar Dronamraju
2011-09-20 12:00 ` [PATCH v5 3.1.0-rc4-tip 2/26] Uprobes: Allow multiple consumers for an uprobe Srikar Dronamraju
2011-09-26 12:29 ` Peter Zijlstra
2011-09-20 12:00 ` [PATCH v5 3.1.0-rc4-tip 3/26] Uprobes: register/unregister probes Srikar Dronamraju
2011-09-20 16:50 ` Stefan Hajnoczi
2011-09-21 4:07 ` Srikar Dronamraju
2011-09-26 13:15 ` Peter Zijlstra
2011-09-26 13:23 ` Srikar Dronamraju
2011-10-03 12:46 ` Oleg Nesterov
2011-10-05 17:04 ` Srikar Dronamraju
2011-10-05 18:50 ` Oleg Nesterov
2011-10-06 6:51 ` Srikar Dronamraju
2011-10-07 17:03 ` Oleg Nesterov
2011-09-20 12:00 ` [PATCH v5 3.1.0-rc4-tip 4/26] uprobes: Define hooks for mmap/munmap Srikar Dronamraju
2011-09-20 17:03 ` Stefan Hajnoczi
2011-09-21 4:03 ` Srikar Dronamraju
2011-09-26 13:53 ` Peter Zijlstra
2011-09-26 15:44 ` Srikar Dronamraju
2011-09-27 11:37 ` Peter Zijlstra
2011-09-27 13:08 ` Srikar Dronamraju
2011-09-27 11:41 ` Peter Zijlstra
2011-09-27 12:59 ` Srikar Dronamraju
2011-09-27 11:42 ` Peter Zijlstra
2011-10-03 13:37 ` Oleg Nesterov
2011-10-06 11:05 ` Srikar Dronamraju
2011-10-07 17:36 ` Oleg Nesterov
2011-10-10 12:31 ` Srikar Dronamraju
2011-09-20 12:00 ` [PATCH v5 3.1.0-rc4-tip 5/26] Uprobes: copy of the original instruction Srikar Dronamraju
2011-10-03 16:29 ` Oleg Nesterov
2011-10-05 10:52 ` Srikar Dronamraju
2011-10-05 15:11 ` Oleg Nesterov
2011-10-05 16:09 ` Srikar Dronamraju
2011-10-05 17:53 ` Oleg Nesterov
2011-09-20 12:01 ` [PATCH v5 3.1.0-rc4-tip 6/26] Uprobes: define fixups Srikar Dronamraju
2011-09-20 12:01 ` [PATCH v5 3.1.0-rc4-tip 7/26] Uprobes: uprobes arch info Srikar Dronamraju
2011-09-20 12:01 ` [PATCH v5 3.1.0-rc4-tip 8/26] x86: analyze instruction and determine fixups Srikar Dronamraju
2011-09-20 17:13 ` Stefan Hajnoczi
2011-09-20 18:12 ` Christoph Hellwig
2011-09-20 20:53 ` Stefan Hajnoczi
2011-09-23 11:53 ` Masami Hiramatsu
2011-09-23 16:51 ` Stefan Hajnoczi
2011-09-26 19:59 ` Josh Stone
2011-09-27 1:32 ` Masami Hiramatsu
2011-09-27 2:59 ` Josh Stone
2011-09-27 7:08 ` Stefan Hajnoczi
2011-09-22 1:05 ` Josh Stone
2011-10-05 15:48 ` Oleg Nesterov
2011-10-05 16:12 ` Srikar Dronamraju
2011-09-20 12:01 ` [PATCH v5 3.1.0-rc4-tip 9/26] Uprobes: Background page replacement Srikar Dronamraju
2011-10-05 16:19 ` Oleg Nesterov
2011-10-06 6:53 ` Srikar Dronamraju
2011-09-20 12:01 ` [PATCH v5 3.1.0-rc4-tip 10/26] x86: Set instruction pointer Srikar Dronamraju
2011-10-05 16:29 ` Oleg Nesterov
2011-09-20 12:02 ` [PATCH v5 3.1.0-rc4-tip 11/26] x86: Introduce TIF_UPROBE FLAG Srikar Dronamraju
2011-09-20 12:02 ` [PATCH v5 3.1.0-rc4-tip 12/26] Uprobes: Handle breakpoint and Singlestep Srikar Dronamraju
2011-09-26 13:59 ` Peter Zijlstra
2011-09-26 16:01 ` Srikar Dronamraju
2011-09-26 16:25 ` Peter Zijlstra
2011-10-05 17:48 ` Oleg Nesterov
2011-09-26 14:02 ` Peter Zijlstra
2011-10-07 18:28 ` Oleg Nesterov
2011-10-09 13:31 ` Oleg Nesterov
2011-09-20 12:02 ` [PATCH v5 3.1.0-rc4-tip 13/26] x86: define a x86 specific exception notifier Srikar Dronamraju
2011-09-26 14:19 ` Peter Zijlstra
2011-09-26 15:52 ` Srikar Dronamraju
2011-09-27 11:46 ` Peter Zijlstra
2011-10-07 18:31 ` Oleg Nesterov
2011-09-20 12:02 ` [PATCH v5 3.1.0-rc4-tip 14/26] uprobe: register " Srikar Dronamraju
2011-09-20 12:03 ` [PATCH v5 3.1.0-rc4-tip 15/26] x86: Define x86_64 specific uprobe_task_arch_info structure Srikar Dronamraju
2011-09-20 12:03 ` [PATCH v5 3.1.0-rc4-tip 16/26] uprobes: Introduce " Srikar Dronamraju
2011-09-20 12:03 ` [PATCH v5 3.1.0-rc4-tip 17/26] x86: arch specific hooks for pre/post singlestep handling Srikar Dronamraju
2011-09-26 14:23 ` Peter Zijlstra
2011-09-26 16:34 ` Srikar Dronamraju
2011-09-27 11:44 ` Peter Zijlstra
2011-09-20 12:03 ` [PATCH v5 3.1.0-rc4-tip 18/26] uprobes: slot allocation Srikar Dronamraju
2011-09-27 11:49 ` Peter Zijlstra
2011-09-27 12:32 ` Srikar Dronamraju
2011-09-27 12:59 ` Peter Zijlstra
2011-09-27 12:18 ` Peter Zijlstra
2011-09-27 12:45 ` Srikar Dronamraju
2011-09-27 12:36 ` Peter Zijlstra
2011-09-27 12:37 ` Peter Zijlstra
2011-09-27 12:50 ` Srikar Dronamraju
2011-09-27 12:50 ` Peter Zijlstra
2011-09-27 12:55 ` Peter Zijlstra
2011-10-07 18:37 ` Oleg Nesterov
2011-10-09 11:47 ` Srikar Dronamraju
2011-09-20 12:03 ` [PATCH v5 3.1.0-rc4-tip 19/26] tracing: Extract out common code for kprobes/uprobes traceevents Srikar Dronamraju
2011-09-28 5:04 ` Masami Hiramatsu
2011-09-20 12:04 ` [PATCH v5 3.1.0-rc4-tip 20/26] tracing: uprobes trace_event interface Srikar Dronamraju
2011-09-20 12:04 ` [PATCH v5 3.1.0-rc4-tip 21/26] tracing: uprobes Documentation Srikar Dronamraju
2011-09-20 12:04 ` [PATCH v5 3.1.0-rc4-tip 22/26] perf: rename target_module to target Srikar Dronamraju
2011-09-20 12:04 ` [PATCH v5 3.1.0-rc4-tip 23/26] perf: perf interface for uprobes Srikar Dronamraju
2011-09-20 12:04 ` [PATCH v5 3.1.0-rc4-tip 24/26] perf: show possible probes in a given executable file or library Srikar Dronamraju
2011-09-20 12:05 ` [PATCH v5 3.1.0-rc4-tip 25/26] perf: Documentation for perf uprobes Srikar Dronamraju
2011-09-28 9:20 ` Masami Hiramatsu
2011-09-20 12:05 ` [PATCH v5 3.1.0-rc4-tip 26/26] uprobes: queue signals while thread is singlestepping Srikar Dronamraju
2011-09-27 13:03 ` Peter Zijlstra
2011-09-27 13:12 ` Srikar Dronamraju
2011-10-05 18:01 ` Oleg Nesterov
2011-10-06 5:47 ` Srikar Dronamraju
2011-10-07 16:58 ` Oleg Nesterov
2011-10-10 12:25 ` Srikar Dronamraju
2011-10-10 18:25 ` Oleg Nesterov
2011-10-11 17:24 ` Oleg Nesterov
2011-10-11 17:38 ` Srikar Dronamraju
2011-10-11 17:26 ` Srikar Dronamraju
2011-10-11 18:56 ` Oleg Nesterov
2011-10-12 12:01 ` Srikar Dronamraju
2011-10-12 19:34 ` Oleg Nesterov
2011-10-12 19:59 ` Oleg Nesterov
2011-09-20 13:34 ` [PATCH v5 3.1.0-rc4-tip 0/26] Uprobes patchset with perf probe support Christoph Hellwig
2011-09-20 14:12 ` Srikar Dronamraju
2011-09-20 14:28 ` Christoph Hellwig
2011-09-20 15:19 ` Srikar Dronamraju
2011-10-15 19:00 ` [PATCH 0/X] (Was: Uprobes patchset with perf probe support) Oleg Nesterov
2011-10-15 19:00 ` [PATCH 1/X] uprobes: write_opcode: the new page needs PG_uptodate Oleg Nesterov
2011-10-17 10:59 ` Srikar Dronamraju
2011-10-15 19:00 ` [PATCH 2/X] uprobes: write_opcode() needs put_page(new_page) unconditionally Oleg Nesterov
2011-10-18 16:47 ` Srikar Dronamraju
2011-10-15 19:01 ` [PATCH 3/X] uprobes: xol_add_vma: fix ->uprobes_xol_area initialization Oleg Nesterov
2011-10-15 19:01 ` [PATCH 4/X] uprobes: xol_add_vma: misc cleanups Oleg Nesterov
2011-10-15 19:01 ` [PATCH 5/X] uprobes: xol_alloc_area() needs memory barriers Oleg Nesterov
2011-10-16 16:13 ` [PATCH 6/X] uprobes: reimplement xol_add_vma() via install_special_mapping() Oleg Nesterov
2011-10-17 10:50 ` Srikar Dronamraju
2011-10-17 13:34 ` Stephen Smalley
2011-10-17 18:55 ` Oleg Nesterov
2011-10-16 16:14 ` [PATCH 7/X] uprobes: xol_add_vma: simply use TASK_SIZE as a hint Oleg Nesterov
2011-10-19 21:51 ` [PATCH 8-14/X] (Was: Uprobes patchset with perf probe support) Oleg Nesterov
2011-10-19 21:52 ` [PATCH 8/X] uprobes: kill sstep_complete() Oleg Nesterov
2011-10-19 21:52 ` [PATCH 9/X] uprobes: introduce UTASK_SSTEP_ACK state Oleg Nesterov
2011-10-19 21:52 ` [PATCH 10/X] uprobes: introduce uprobe_deny_signal() Oleg Nesterov
2011-10-19 21:53 ` [PATCH 11/X] uprobes: x86: introduce xol_was_trapped() Oleg Nesterov
2011-10-24 14:55 ` Srikar Dronamraju
2011-10-24 16:07 ` Oleg Nesterov
2011-10-19 21:53 ` [PATCH 12/X] uprobes: x86: introduce abort_xol() Oleg Nesterov
2011-10-21 14:42 ` Srikar Dronamraju
2011-10-21 16:22 ` Oleg Nesterov
2011-10-21 16:26 ` Ananth N Mavinakayanahalli
2011-10-21 16:42 ` Oleg Nesterov
2011-10-21 17:59 ` test-case (Was: [PATCH 12/X] uprobes: x86: introduce abort_xol()) Oleg Nesterov
2011-10-25 14:06 ` Srikar Dronamraju
2011-10-25 15:49 ` Oleg Nesterov
2011-10-22 7:09 ` [PATCH 12/X] uprobes: x86: introduce abort_xol() Ananth N Mavinakayanahalli
2011-10-19 21:53 ` [PATCH 13/X] uprobes: introduce UTASK_SSTEP_TRAPPED logic Oleg Nesterov
2011-10-22 7:20 ` Ananth N Mavinakayanahalli
2011-10-24 14:41 ` Oleg Nesterov
2011-10-24 15:16 ` Ananth N Mavinakayanahalli [this message]
2011-10-24 16:13 ` Oleg Nesterov
2011-10-25 6:01 ` Ananth N Mavinakayanahalli
2011-10-25 14:30 ` Oleg Nesterov
2011-10-19 21:54 ` [PATCH 14/X] uprobes: uprobe_deny_signal: check __fatal_signal_pending() Oleg Nesterov
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