From: Will Deacon <will.deacon@arm.com>
To: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: skip dump_backtrace() in show_regs when user mode pt_regs
Date: Wed, 3 Apr 2019 13:44:20 +0100 [thread overview]
Message-ID: <20190403124420.GF16362@fuggles.cambridge.arm.com> (raw)
In-Reply-To: <20190328114527.171178-1-wangkefeng.wang@huawei.com>
On Thu, Mar 28, 2019 at 07:45:27PM +0800, Kefeng Wang wrote:
> There is no need to call dump_backtrace() when the pt_regs
> corresponds to user mode, eg,
>
> [ 334.634005] potentially unexpected fatal signal 11.
> [ 334.634476] CPU: 3 PID: 2049 Comm: test Not tainted 5.1.0-rc2 #24
> [ 334.634745] Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
> [ 334.635786] pstate: 60001000 (nZCv daif -PAN -UAO)
> [ 334.636131] pc : 0000aaaaad4c0788
> [ 334.636725] lr : 0000ffff83aac6e0
> [ 334.637006] sp : 0000ffffd14e9670
> [ 334.637352] x29: 0000ffffd14e9690 x28: 0000000000000000
> [ 334.637814] x27: 0000000000000000 x26: 0000000000000000
> [ 334.638143] x25: 0000000000000000 x24: 0000000000000000
> [ 334.638460] x23: 0000000000000000 x22: 0000000000000000
> [ 334.639499] x21: 0000aaaaad4c0650 x20: 0000000000000000
> [ 334.640336] x19: 0000aaaaad4c0790 x18: 0000000000000002
> [ 334.641062] x17: 0000ffff83aac600 x16: 0000aaaaad4d0fa0
> [ 334.641474] x15: 0000ffff83c10150 x14: 0000ffff83c101e0
> [ 334.641894] x13: 0000ffff83c12048 x12: 0000000000000000
> [ 334.642421] x11: 0000000000010000 x10: 0000000008000000
> [ 334.642749] x9 : 000000000fffffff x8 : ffffffffffffffff
> [ 334.643378] x7 : 0000000000010000 x6 : 0000ffff83be0b00
> [ 334.643669] x5 : 0000000000000000 x4 : 0000000000000000
> [ 334.644012] x3 : 0000aaaaad4c0754 x2 : 0000ffffd14e97d8
> [ 334.644302] x1 : 0000fffefffffffc x0 : 0000ffff00000000
> [ 334.645211] Call trace:
>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
> arch/arm64/kernel/process.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> index 3767fb21a5b8..de224f1512ca 100644
> --- a/arch/arm64/kernel/process.c
> +++ b/arch/arm64/kernel/process.c
> @@ -298,7 +298,8 @@ void __show_regs(struct pt_regs *regs)
> void show_regs(struct pt_regs * regs)
> {
> __show_regs(regs);
> - dump_backtrace(regs, NULL);
> + if (!user_mode(regs))
> + dump_backtrace(regs, NULL);
> }
Wouldn't this check be better off inside dump_backtrace()?
Will
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next prev parent reply other threads:[~2019-04-03 12:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-28 11:45 [PATCH] arm64: skip dump_backtrace() in show_regs when user mode pt_regs Kefeng Wang
2019-04-03 12:44 ` Will Deacon [this message]
2019-04-03 15:58 ` Kefeng Wang
2019-04-05 16:42 ` Will Deacon
2019-04-07 7:38 ` Kefeng Wang
2019-04-08 17:05 ` Will Deacon
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