From: Catalin Marinas <catalin.marinas@arm.com>
To: "haibinzhang(张海斌)" <haibinzhang@tencent.com>
Cc: Will Deacon <will@kernel.org>,
Ard Biesheuvel <ard.biesheuvel@arm.com>,
Martin Ma <Martin.Ma@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"hewenliang4@huawei.com" <hewenliang4@huawei.com>
Subject: Re: [PATCH V2] arm64: fix oops in concurrently setting insn_emulation sysctls
Date: Mon, 4 Jul 2022 11:34:02 +0100 [thread overview]
Message-ID: <YsLCGsagWulawWIl@arm.com> (raw)
In-Reply-To: <9A004C03-250B-46C5-BF39-782D7551B00E@tencent.com>
On Sat, Jul 02, 2022 at 05:43:19AM +0000, haibinzhang(张海斌) wrote:
> How to reproduce:
> launch two shell executions:
> #!/bin/bash
> while [ 1 ];
> do
> echo 1 > /proc/sys/abi/swp
> done
>
> Oops info:
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
> Internal error: Oops: 96000006 [#1] SMP
> Call trace:
> update_insn_emulation_mode+0xc0/0x148
> emulation_proc_handler+0x64/0xb8
> proc_sys_call_handler+0x9c/0xf8
> proc_sys_write+0x18/0x20
> __vfs_write+0x20/0x48
> vfs_write+0xe4/0x1d0
> ksys_write+0x70/0xf8
> __arm64_sys_write+0x20/0x28
> el0_svc_common.constprop.0+0x7c/0x1c0
> el0_svc_handler+0x2c/0xa0
> el0_svc+0x8/0x200
>
> emulation_proc_handler changes table->data for proc_dointvec_minmax
> and so it isn't allowed to reenter before restoring table->data,
> which isn't right now.
> To fix this issue, keep the table->data as &insn->current_mode and
> use container_of() to retrieve the insn pointer. Another mutex is
> used to protect against the current_mode update but not for retrieving
> insn_emulation as table->data is no longer changing.
>
> Signed-off-by: hewenliang <hewenliang4@huawei.com>
> Signed-off-by: Haibin Zhang <haibinzhang@tencent.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com>
To: "haibinzhang(张海斌)" <haibinzhang@tencent.com>
Cc: Will Deacon <will@kernel.org>,
Ard Biesheuvel <ard.biesheuvel@arm.com>,
Martin Ma <Martin.Ma@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"hewenliang4@huawei.com" <hewenliang4@huawei.com>
Subject: Re: [PATCH V2] arm64: fix oops in concurrently setting insn_emulation sysctls
Date: Mon, 4 Jul 2022 11:34:02 +0100 [thread overview]
Message-ID: <YsLCGsagWulawWIl@arm.com> (raw)
In-Reply-To: <9A004C03-250B-46C5-BF39-782D7551B00E@tencent.com>
On Sat, Jul 02, 2022 at 05:43:19AM +0000, haibinzhang(张海斌) wrote:
> How to reproduce:
> launch two shell executions:
> #!/bin/bash
> while [ 1 ];
> do
> echo 1 > /proc/sys/abi/swp
> done
>
> Oops info:
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
> Internal error: Oops: 96000006 [#1] SMP
> Call trace:
> update_insn_emulation_mode+0xc0/0x148
> emulation_proc_handler+0x64/0xb8
> proc_sys_call_handler+0x9c/0xf8
> proc_sys_write+0x18/0x20
> __vfs_write+0x20/0x48
> vfs_write+0xe4/0x1d0
> ksys_write+0x70/0xf8
> __arm64_sys_write+0x20/0x28
> el0_svc_common.constprop.0+0x7c/0x1c0
> el0_svc_handler+0x2c/0xa0
> el0_svc+0x8/0x200
>
> emulation_proc_handler changes table->data for proc_dointvec_minmax
> and so it isn't allowed to reenter before restoring table->data,
> which isn't right now.
> To fix this issue, keep the table->data as &insn->current_mode and
> use container_of() to retrieve the insn pointer. Another mutex is
> used to protect against the current_mode update but not for retrieving
> insn_emulation as table->data is no longer changing.
>
> Signed-off-by: hewenliang <hewenliang4@huawei.com>
> Signed-off-by: Haibin Zhang <haibinzhang@tencent.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
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next prev parent reply other threads:[~2022-07-04 10:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-02 5:43 [PATCH V2] arm64: fix oops in concurrently setting insn_emulation sysctls haibinzhang(张海斌)
2022-07-02 5:43 ` haibinzhang(张海斌)
2022-07-04 10:34 ` Catalin Marinas [this message]
2022-07-04 10:34 ` Catalin Marinas
2022-07-04 14:27 ` Will Deacon
2022-07-04 14:27 ` Will Deacon
2022-07-20 12:23 ` Lee Jones
2022-07-20 12:23 ` Lee Jones
2022-07-20 15:13 ` Will Deacon
2022-07-20 15:13 ` Will Deacon
2022-07-20 15:33 ` Lee Jones
2022-07-20 15:33 ` Lee Jones
2022-07-20 16:11 ` Will Deacon
2022-07-20 16:11 ` Will Deacon
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