From: Shaobo Huang <huangshaobo6@huawei.com>
To: <ardb@kernel.org>, <dvyukov@google.com>, <f.fainelli@gmail.com>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, <linux@armlinux.org.uk>,
<nico@marvell.com>, <qbarnes@gmail.com>,
<sagar.abhishek@gmail.com>
Cc: <chenzefeng2@huawei.com>, <huangshaobo6@huawei.com>,
<kepler.chenxin@huawei.com>, <liucheng32@huawei.com>,
<liuwenliang@huawei.com>, <nixiaoming@huawei.com>,
<wuquanming@huawei.com>, <young.liuyang@huawei.com>,
<zengweilin@huawei.com>
Subject: Re: [PATCH] ARM: fix panic when kasan and kprobe are enabled
Date: Thu, 8 Jul 2021 12:14:09 +0800 [thread overview]
Message-ID: <20210708041409.34168-1-huangshaobo6@huawei.com> (raw)
In-Reply-To: <CAMj1kXGqfF68MT4WwrxS0cYiUBb0gODDh-wGZSQcW9vxdfK90A@mail.gmail.com>
On Thu, 11 Feb 2021 at 09:40, Ard Biesheuvel <ardb@kernel.org> wrote:
>
> > From: huangshaobo <huangshaobo6@huawei.com>
> >
> > arm32 uses software to simulate the instruction replaced
> > by kprobe. some instructions may be simulated by constructing
> > assembly functions. therefore, before executing instruction
> > simulation, it is necessary to construct assembly function
> > execution environment in C language through binding registers.
> > after kasan is enabled, the register binding relationship will
> > be destroyed, resulting in instruction simulation errors and
> > causing kernel panic.
> >
> > the kprobe emulate instruction function is distributed in three
> > files: actions-common.c actions-arm.c actions-thumb.c, so disable
> > KASAN when compiling these files.
> >
> > for example, use kprobe insert on cap_capable+20 after kasan
> > enabled, the cap_capable assembly code is as follows:
> > <cap_capable>:
> > e92d47f0 push {r4, r5, r6, r7, r8, r9, sl, lr}
> > e1a05000 mov r5, r0
> > e280006c add r0, r0, #108 ; 0x6c
> > e1a04001 mov r4, r1
> > e1a06002 mov r6, r2
> > e59fa090 ldr sl, [pc, #144] ;
> > ebfc7bf8 bl c03aa4b4 <__asan_load4>
> > e595706c ldr r7, [r5, #108] ; 0x6c
> > e2859014 add r9, r5, #20
> > ......
> > The emulate_ldr assembly code after enabling kasan is as follows:
> > c06f1384 <emulate_ldr>:
> > e92d47f0 push {r4, r5, r6, r7, r8, r9, sl, lr}
> > e282803c add r8, r2, #60 ; 0x3c
> > e1a05000 mov r5, r0
> > e7e37855 ubfx r7, r5, #16, #4
> > e1a00008 mov r0, r8
> > e1a09001 mov r9, r1
> > e1a04002 mov r4, r2
> > ebf35462 bl c03c6530 <__asan_load4>
> > e357000f cmp r7, #15
> > e7e36655 ubfx r6, r5, #12, #4
> > e205a00f and sl, r5, #15
> > 0a000001 beq c06f13bc <emulate_ldr+0x38>
> > e0840107 add r0, r4, r7, lsl #2
> > ebf3545c bl c03c6530 <__asan_load4>
> > e084010a add r0, r4, sl, lsl #2
> > ebf3545a bl c03c6530 <__asan_load4>
> > e2890010 add r0, r9, #16
> > ebf35458 bl c03c6530 <__asan_load4>
> > e5990010 ldr r0, [r9, #16]
> > e12fff30 blx r0
> > e356000f cm r6, #15
> > 1a000014 bne c06f1430 <emulate_ldr+0xac>
> > e1a06000 mov r6, r0
> > e2840040 add r0, r4, #64 ; 0x40
> > ......
> > when running in emulate_ldr to simulate the ldr instruction, panic
> > occurred, and the log is as follows:
> > Unable to handle kernel NULL pointer dereference at virtual address
> > 00000090
> > pgd = ecb46400
> > [00000090] *pgd=2e0fa003, *pmd=00000000
> > Internal error: Oops: 206 [#1] SMP ARM
> > PC is at cap_capable+0x14/0xb0
> > LR is at emulate_ldr+0x50/0xc0
> > psr: 600d0293 sp : ecd63af8 ip : 00000004 fp : c0a7c30c
> > r10: 00000000 r9 : c30897f4 r8 : ecd63cd4
> > r7 : 0000000f r6 : 0000000a r5 : e59fa090 r4 : ecd63c98
> > r3 : c06ae294 r2 : 00000000 r1 : b7611300 r0 : bf4ec008
> > Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment user
> > Control: 32c5387d Table: 2d546400 DAC: 55555555
> > Process bash (pid: 1643, stack limit = 0xecd60190)
> > (cap_capable) from (kprobe_handler+0x218/0x340)
> > (kprobe_handler) from (kprobe_trap_handler+0x24/0x48)
> > (kprobe_trap_handler) from (do_undefinstr+0x13c/0x364)
> > (do_undefinstr) from (__und_svc_finish+0x0/0x30)
> > (__und_svc_finish) from (cap_capable+0x18/0xb0)
> > (cap_capable) from (cap_vm_enough_memory+0x38/0x48)
> > (cap_vm_enough_memory) from
> > (security_vm_enough_memory_mm+0x48/0x6c)
> > (security_vm_enough_memory_mm) from
> > (copy_process.constprop.5+0x16b4/0x25c8)
> > (copy_process.constprop.5) from (_do_fork+0xe8/0x55c)
> > (_do_fork) from (SyS_clone+0x1c/0x24)
> > (SyS_clone) from (__sys_trace_return+0x0/0x10)
> > Code: 0050a0e1 6c0080e2 0140a0e1 0260a0e1 (f801f0e7)
> >
> > Fixes: 35aa1df43283 ("ARM kprobes: instruction single-stepping support")
> > Fixes: 421015713b30 ("ARM: 9017/2: Enable KASan for ARM")
> > Signed-off-by: huangshaobo <huangshaobo6@huawei.com>
> Acked-by: Ard Biesheuvel <ardb@kernel.org>
Maintainer ping?
thanks,
ShaoBo Huang
next prev parent reply other threads:[~2021-07-08 4:14 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-09 8:55 [PATCH] ARM: fix panic when kasan and kprobe are enabled Shaobo Huang
2021-02-11 8:40 ` Ard Biesheuvel
2021-07-08 4:14 ` Shaobo Huang [this message]
2021-07-14 8:27 ` Shaobo Huang
2021-07-16 17:01 ` Ard Biesheuvel
2021-07-19 3:09 ` Shaobo Huang
2021-07-19 7:06 ` Ard Biesheuvel
2021-07-19 7:45 ` Shaobo Huang
2021-07-19 7:51 ` Ard Biesheuvel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210708041409.34168-1-huangshaobo6@huawei.com \
--to=huangshaobo6@huawei.com \
--cc=ardb@kernel.org \
--cc=chenzefeng2@huawei.com \
--cc=dvyukov@google.com \
--cc=f.fainelli@gmail.com \
--cc=kepler.chenxin@huawei.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=liucheng32@huawei.com \
--cc=liuwenliang@huawei.com \
--cc=nico@marvell.com \
--cc=nixiaoming@huawei.com \
--cc=qbarnes@gmail.com \
--cc=sagar.abhishek@gmail.com \
--cc=wuquanming@huawei.com \
--cc=young.liuyang@huawei.com \
--cc=zengweilin@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).