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From: Catalin Marinas <catalin.marinas@arm.com>
To: Pratyush Anand <panand@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	srikar@linux.vnet.ibm.com, Will Deacon <will.deacon@arm.com>,
	Oleg Nesterov <oleg@redhat.com>,
	Jungseok Lee <jungseoklee85@gmail.com>,
	Russell King - ARM Linux <linux@arm.linux.org.uk>,
	vijaya.kumar@caviumnetworks.com, Dave Long <dave.long@linaro.org>,
	Shi Yang <yang.shi@linaro.org>,
	Vladimir Murzin <vladimir.murzin@arm.com>,
	Steve Capper <steve.capper@linaro.org>,
	"Suzuki K. Poulose" <suzuki.poulose@arm.com>,
	Andre Przywara <andre.przywara@arm.com>,
	Shaokun Zhang <zhangshaokun@hisilicon.com>,
	Ashok Kumar <ashoks@broadcom.com>,
	Sandeepa Prabhu <sandeepa.s.prabhu@gmail.com>,
	Will Cohen <wcohen@redhat.com>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	open list <linux-kernel@vger.kernel.org>,
	James Morse <james.morse@arm.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH 5/5] arm64: Add uprobe support
Date: Wed, 28 Sep 2016 18:12:10 +0100	[thread overview]
Message-ID: <20160928171210.GC29934@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <c7675b74-982d-d8b6-935f-a74139820174@redhat.com>

On Tue, Sep 27, 2016 at 08:33:25PM +0530, Pratyush Anand wrote:
> On Tuesday 27 September 2016 07:21 PM, Catalin Marinas wrote:
> >There is also the is_trap_at_addr() function which uses is_trap_insn().
> >I haven't checked the call paths here, are there any implications if
> >is_trap_insn() always returns false?
> 
> I had looked into it and also tested that a tracepoint at an application
> having a same instruction as that of "uprobe break instruction" ie "BRK
> #0x5" is rejected. So, I think a false positive return from is_tarp_insn()
> is still OK.

Looking at handle_swbp(), if we hit a breakpoint for which we don't have
a valid uprobe, this function currently sends a SIGTRAP. But if
is_trap_insn() returns false always, is_trap_at_addr() would return 0 in
this case so the SIGTRAP is never issued.

-- 
Catalin

  reply	other threads:[~2016-09-28 17:12 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-02  5:30 [PATCH 0/5] ARM64: Uprobe support added Pratyush Anand
2016-08-02  5:30 ` [PATCH 1/5] arm64: kprobe: protect/rename few definitions to be reused by uprobe Pratyush Anand
2016-08-02  5:30 ` [PATCH 2/5] arm64: kgdb_step_brk_fn: ignore other's exception Pratyush Anand
2016-08-02  5:30 ` [PATCH 3/5] arm64: Handle TRAP_HWBRKPT for user mode as well Pratyush Anand
2016-09-06 16:11   ` Catalin Marinas
2016-09-06 21:36     ` David Long
2016-09-07  4:47       ` Pratyush Anand
2016-09-07 13:41       ` Catalin Marinas
2016-08-02  5:30 ` [PATCH 4/5] arm64: Handle TRAP_BRKPT " Pratyush Anand
2016-09-06 16:34   ` Catalin Marinas
2016-08-02  5:30 ` [PATCH 5/5] arm64: Add uprobe support Pratyush Anand
2016-08-09 18:49   ` Oleg Nesterov
2016-08-24  7:13     ` Pratyush Anand
2016-08-24 15:47       ` Oleg Nesterov
2016-08-24 15:56         ` Will Deacon
2016-08-25 13:33           ` Oleg Nesterov
2016-09-20 16:59   ` Catalin Marinas
2016-09-21 11:00     ` Pratyush Anand
2016-09-21 17:04       ` Catalin Marinas
2016-09-22  3:23         ` Pratyush Anand
2016-09-22 16:50           ` Catalin Marinas
2016-09-23  4:12             ` Pratyush Anand
2016-09-23 13:05               ` Catalin Marinas
2016-09-25 17:02                 ` Pratyush Anand
2016-09-26 11:01                   ` Catalin Marinas
2016-09-26 13:03                     ` Pratyush Anand
2016-09-27 13:51                       ` Catalin Marinas
2016-09-27 15:03                         ` Pratyush Anand
2016-09-28 17:12                           ` Catalin Marinas [this message]
2016-08-24  7:26 ` [PATCH 0/5] ARM64: Uprobe support added Pratyush Anand
2016-09-20  2:51   ` Pratyush Anand

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