From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <peterz@infradead.org>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Anton Arapov <anton@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/7] uprobes: introduce MMF_HAS_UPROBES
Date: Mon, 13 Aug 2012 18:52:21 +0530 [thread overview]
Message-ID: <20120813132221.GJ31805@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120808173747.GA13272@redhat.com>
* Oleg Nesterov <oleg@redhat.com> [2012-08-08 19:37:47]:
> Add the new MMF_HAS_UPROBES flag. It is set by install_breakpoint()
> and it is copied by dup_mmap(), uprobe_pre_sstep_notifier() checks
> it to avoid the slow path if the task was never probed. Perhaps it
> makes sense to check it in valid_vma(is_register => false) as well.
>
> This needs the new dup_mmap()->uprobe_dup_mmap() hook. We can't use
> uprobe_reset_state() or put MMF_HAS_UPROBES into MMF_INIT_MASK, we
> need oldmm->mmap_sem to avoid the race with uprobe_register() or
> mmap() from another thread.
>
> Currently we never clear this bit, it can be false-positive after
> uprobe_unregister() or uprobe_munmap() or if dup_mmap() hits the
> probed VM_DONTCOPY vma. But this is fine correctness-wise and has
> no effect unless the task hits the non-uprobe breakpoint.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
next prev parent reply other threads:[~2012-08-13 13:23 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-08 17:36 [PATCH 0/7] uprobes: kill uprobes_state->count, add MMF_HAS_UPROBES Oleg Nesterov
2012-08-08 17:37 ` [PATCH 1/7] uprobes: kill uprobes_state->count Oleg Nesterov
2012-08-13 13:18 ` Srikar Dronamraju
2012-08-08 17:37 ` [PATCH 2/7] uprobes: kill dup_mmap()->uprobe_mmap(), simplify uprobe_mmap/munmap Oleg Nesterov
2012-08-13 13:20 ` Srikar Dronamraju
2012-08-08 17:37 ` [PATCH 3/7] uprobes: change uprobe_mmap() to ignore the errors but check fatal_signal_pending() Oleg Nesterov
2012-08-13 13:21 ` Srikar Dronamraju
2012-08-08 17:37 ` [PATCH 4/7] uprobes: do not use -EEXIST in install_breakpoint() paths Oleg Nesterov
2012-08-13 13:21 ` Srikar Dronamraju
2012-08-08 17:37 ` [PATCH 5/7] uprobes: introduce MMF_HAS_UPROBES Oleg Nesterov
2012-08-09 13:32 ` Srikar Dronamraju
2012-08-09 14:17 ` Oleg Nesterov
2012-08-13 13:22 ` Srikar Dronamraju [this message]
2012-08-08 17:37 ` [PATCH 6/7] uprobes: fold uprobe_reset_state() into uprobe_dup_mmap() Oleg Nesterov
2012-08-13 13:23 ` Srikar Dronamraju
2012-08-08 17:37 ` [PATCH 7/7] uprobes: remove "verify" argument from set_orig_insn() Oleg Nesterov
2012-08-09 13:33 ` Srikar Dronamraju
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