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From: Oleg Nesterov <oleg@redhat.com>
To: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: srikar@linux.vnet.ibm.com, rostedt@goodmis.org,
	mhiramat@kernel.org, liu.song.a23@gmail.com,
	peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
	alexander.shishkin@linux.intel.com, jolsa@redhat.com,
	namhyung@kernel.org, linux-kernel@vger.kernel.org,
	ananth@linux.vnet.ibm.com, alexis.berlemont@gmail.com,
	naveen.n.rao@linux.vnet.ibm.com,
	linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org,
	linux@armlinux.org.uk, ralf@linux-mips.org, paul.burton@mips.com
Subject: Re: [PATCH] Uprobes: Fix kernel oops with delayed_uprobe_remove()
Date: Thu, 15 Nov 2018 13:43:18 +0100	[thread overview]
Message-ID: <20181115124317.GA23272@redhat.com> (raw)
In-Reply-To: <556c2aa5-550d-d96f-7ed2-549d8f3d803b@linux.ibm.com>

On 11/15, Ravi Bangoria wrote:
>
> There could be a race between task exit and probe unregister:
>
>   exit_mm()
>   mmput()
>   __mmput()                     uprobe_unregister()
>   uprobe_clear_state()          put_uprobe()
>   delayed_uprobe_remove()       delayed_uprobe_remove()
>
> put_uprobe() is calling delayed_uprobe_remove() without taking
> delayed_uprobe_lock and thus the race sometimes results in a
> kernel crash. Fix this by taking delayed_uprobe_lock before
> calling delayed_uprobe_remove() from put_uprobe().
>
> Detailed crash log can be found at:
>   https://lkml.org/lkml/2018/11/1/1244

Thanks, looks good,

Oleg.

WARNING: multiple messages have this Message-ID (diff)
From: oleg@redhat.com (Oleg Nesterov)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] Uprobes: Fix kernel oops with delayed_uprobe_remove()
Date: Thu, 15 Nov 2018 13:43:18 +0100	[thread overview]
Message-ID: <20181115124317.GA23272@redhat.com> (raw)
In-Reply-To: <556c2aa5-550d-d96f-7ed2-549d8f3d803b@linux.ibm.com>

On 11/15, Ravi Bangoria wrote:
>
> There could be a race between task exit and probe unregister:
>
>   exit_mm()
>   mmput()
>   __mmput()                     uprobe_unregister()
>   uprobe_clear_state()          put_uprobe()
>   delayed_uprobe_remove()       delayed_uprobe_remove()
>
> put_uprobe() is calling delayed_uprobe_remove() without taking
> delayed_uprobe_lock and thus the race sometimes results in a
> kernel crash. Fix this by taking delayed_uprobe_lock before
> calling delayed_uprobe_remove() from put_uprobe().
>
> Detailed crash log can be found at:
>   https://lkml.org/lkml/2018/11/1/1244

Thanks, looks good,

Oleg.

  reply	other threads:[~2018-11-15 12:44 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-14  8:19 [PATCH] Uprobes: Fix kernel oops with delayed_uprobe_remove() Ravi Bangoria
2018-11-14  8:19 ` Ravi Bangoria
2018-11-14 16:06 ` Oleg Nesterov
2018-11-14 16:06   ` Oleg Nesterov
2018-11-15  4:06   ` Ravi Bangoria
2018-11-15  4:06     ` Ravi Bangoria
2018-11-15 12:43     ` Oleg Nesterov [this message]
2018-11-15 12:43       ` Oleg Nesterov
2018-12-03  6:22       ` Ravi Bangoria
2018-12-04  5:58         ` Steven Rostedt
2018-12-05  3:34           ` [PATCH v2] " Ravi Bangoria
2018-12-05 10:01             ` Srikar Dronamraju
2018-12-05 14:39             ` Oleg Nesterov

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