Hi lianbo
only test step.
rm -rf gdb-10.2/
make target=arm64
Thanks
Guanyou
lijiang <liji...@redhat.com> 于2025年1月16日周四 14:58写道：
>
>
> On Wed, Jan 15, 2025 at 9:29 PM Guanyou Chen <chenguanyou9...@gmail.com>
> wrote:
>
>> Hi lianbo
>>
>> attached pacth v3.
>>
>
> Thank you for the update.
>
> Have you tested patch v3? I got an error and failed to apply the gdb patch:
> ...
> patching file gdb-10.2/gdb/stack.c
> Hunk #1 succeeded at 2130 (offset 3 lines).
> patching file gdb-10.2/gdb/frame.c
> Hunk #1 FAILED at 944.
> 1 out of 2 hunks FAILED
> make[6]: Nothing to be done for 'all'.
> ...
>
> Thanks
> Lianbo
>
>
>> > Can you help double check if a sanity check needs to be added? I saw
>> the value 'pc|mask' is always checked in crash code as below:
>> > ...
>> > LR = regs->regs[30];
>> > if (is_kernel_text (LR |
>> ms->CONFIG_ARM64_KERNELPACMASK))
>> > LR |= ms->CONFIG_ARM64_KERNELPACMASK;
>> > ...
>> > if yes, the value pc can be passed as an argument in
>> crash_get_kernel_pac_mask(), and then deal with this one.
>>
>> /* arm64 kernel lr maybe has patuh */
>> void crash_decode_ptrauth_pc(ulong *pc);
>> void crash_decode_ptrauth_pc(ulong *pc)
>> {
>> #ifdef ARM64
>> struct machine_specific *ms = machdep->machspec;
>> if (is_kernel_text(*pc | ms->CONFIG_ARM64_KERNELPACMASK))
>> *pc |= ms->CONFIG_ARM64_KERNELPACMASK;
>> #endif /* !ARM64 */
>> }
>>
>> Guanyou Chen <chenguanyou9...@gmail.com> 于2025年1月15日周三 17:55写道：
>>
>>> Hi lianbo
>>>
>>> attach patch v2.
>>>
>>> lijiang <liji...@redhat.com> 于2025年1月15日周三 16:42写道：
>>>
>>>> Thank you for the patch, Guanyou.
>>>>
>>>> On Tue, Dec 31, 2024 at 7:22 PM <
>>>> devel-requ...@lists.crash-utility.osci.io> wrote:
>>>>
>>>>> Date: Thu, 26 Dec 2024 00:08:50 +0800
>>>>> From: Guanyou Chen <chenguanyou9...@gmail.com>
>>>>> Subject: [Crash-utility] [PATCH] arm64: add pac mask to better support
>>>>> gdb stack unwind
>>>>> To: Lianbo <liji...@redhat.com>, Tao Liu <l...@redhat.com>,
>>>>> devel@lists.crash-utility.osci.io
>>>>> Message-ID:
>>>>> <
>>>>> cahs3rmxjg6oxb_zmgnr60kripoxo9tnb_63k+rjjhfk1t7a...@mail.gmail.com>
>>>>> Content-Type: multipart/mixed; boundary="0000000000009f35d6062a1a727c"
>>>>>
>>>>> --0000000000009f35d6062a1a727c
>>>>> Content-Type: multipart/alternative;
>>>>> boundary="0000000000009f35d5062a1a727a"
>>>>>
>>>>> --0000000000009f35d5062a1a727a
>>>>> Content-Type: text/plain; charset="UTF-8"
>>>>>
>>>>> Hi Lianbo & Tao
>>>>>
>>>>> Currently, gdb passthroughs of 'bt', 'frame', 'up', 'down',
>>>>> 'info, locals' don't work on arm64 machine enabled pauth.
>>>>> This is due to gdb not knowing the lr register real values
>>>>> to unwind the stack frames.
>>>>>
>>>>> ----------------------------
>>>>> gdb passthrough (eg. "bt") | |
>>>>> crash -------------------------> | |
>>>>> | gdb_interface |
>>>>> | |
>>>>> | |
>>>>> | ---------------------- |
>>>>> get_kernel_pac_mask | | | |
>>>>> crash_target<-------------------------+--| gdb | |
>>>>> --------------------------+->| | |
>>>>> arm64: CONFIG_ARM64_KERNELPACMASK| | | |
>>>>> other: ~0UL | | | |
>>>>> | ---------------------- |
>>>>> ----------------------------
>>>>>
>>>>> With the patch:
>>>>> crash> gdb bt
>>>>> #0 __switch_to (prev=prev@entry=0xffffff8001af92c0,
>>>>> next=next@entry=0xffffff889da7a580)
>>>>> at /proc/self/cwd/common/arch/arm64/kernel/process.c:569
>>>>> #1 0xffffffd3602132c0 in context_switch (rq=0xffffff8a7295a080,
>>>>> prev=0xffffff8001af92c0, next=0xffffff889da7a580, rf=<optimized out>)
>>>>> at
>>>>> /proc/self/cwd/common/kernel/sched/core.c:5515
>>>>> #2 __schedule (sched_mode=<optimized out>, sched_mode@entry
>>>>> =2147859424)
>>>>> at /proc/self/cwd/common/kernel/sched/core.c:6843
>>>>> #3 0xffffffd3602136d8 in schedule () at
>>>>> /proc/self/cwd/common/kernel/sched/core.c:6917
>>>>> ...
>>>>>
>>>>> Without the patch:
>>>>> crash> gdb bt
>>>>> #0 __switch_to (prev=0xffffff8001af92c0, next=0xffffff889da7a580)
>>>>> at
>>>>> /proc/self/cwd/common/arch/arm64/kernel/process.c:569
>>>>> #1 0x9fc5c5d3602132c0 in ?? ()
>>>>> Backtrace stopped: previous frame identical to this frame (corrupt
>>>>> stack?)
>>>>>
>>>>> Signed-off-by: Guanyou.Chen <chenguan...@xiaomi.com>
>>>>> ---
>>>>> gdb-10.2.patch | 24 ++++++++++++++++++++++++
>>>>> gdb_interface.c | 11 +++++++++++
>>>>> 2 files changed, 35 insertions(+)
>>>>>
>>>>> diff --git a/gdb-10.2.patch b/gdb-10.2.patch
>>>>> index c867660..4c13a6b 100644
>>>>> --- a/gdb-10.2.patch
>>>>> +++ b/gdb-10.2.patch
>>>>> @@ -16216,3 +16216,27 @@ exit 0
>>>>> printf_filtered (_("Backtrace stopped: %s\n"),
>>>>> frame_stop_reason_string (trailing));
>>>>> }
>>>>> +--- gdb-10.2/gdb/frame.c.orig
>>>>> ++++ gdb-10.2/gdb/frame.c
>>>>> +@@ -944,6 +944,10 @@ frame_find_by_id (struct frame_id id)
>>>>> + return NULL;
>>>>> + }
>>>>> +
>>>>> ++#ifdef CRASH_MERGE
>>>>> ++extern "C" unsigned long crash_get_kernel_pac_mask(void);
>>>>> ++#endif
>>>>> ++
>>>>> + static CORE_ADDR
>>>>> + frame_unwind_pc (frame_info_ptr this_frame)
>>>>> + {
>>>>> +@@ -974,6 +978,10 @@ frame_unwind_pc (struct frame_info_ptr
>>>>> *this_frame)
>>>>> + try
>>>>> + {
>>>>> + pc = gdbarch_unwind_pc (prev_gdbarch, this_frame);
>>>>> ++#ifdef CRASH_MERGE
>>>>> ++ CORE_ADDR mask = crash_get_kernel_pac_mask();
>>>>> ++ pc |= mask;
>>>>>
>>>>
>>>> Can you help double check if a sanity check needs to be added? I saw
>>>> the value 'pc|mask' is always checked in crash code as below:
>>>> ...
>>>> LR = regs->regs[30];
>>>> if (is_kernel_text (LR |
>>>> ms->CONFIG_ARM64_KERNELPACMASK))
>>>> LR |= ms->CONFIG_ARM64_KERNELPACMASK;
>>>> ...
>>>> if yes, the value pc can be passed as an argument in
>>>> crash_get_kernel_pac_mask(), and then deal with this one.
>>>>
>>>>
>>>>> ++#endif
>>>>> + pc_p = true;
>>>>> + }
>>>>> + catch (const gdb_exception_error &ex)
>>>>> diff --git a/gdb_interface.c b/gdb_interface.c
>>>>> index 315711e..765dafe 100644
>>>>> --- a/gdb_interface.c
>>>>> +++ b/gdb_interface.c
>>>>> @@ -1083,3 +1083,14 @@ int crash_get_current_task_reg (int regno, const
>>>>> char *regname,
>>>>> return machdep->get_current_task_reg(regno, regname, regsize,
>>>>> value);
>>>>> }
>>>>>
>>>>> +/* arm64 kernel lr pac mask */
>>>>> +unsigned long crash_get_kernel_pac_mask(void);
>>>>> +unsigned long crash_get_kernel_pac_mask(void)
>>>>> +{
>>>>> +#ifdef ARM64
>>>>> + struct machine_specific *ms = machdep->machspec;
>>>>> + return ms->CONFIG_ARM64_KERNELPACMASK;
>>>>> +#else
>>>>> + return ~0UL;
>>>>>
>>>>
>>>> The "~0UL" is 0xFFFFFFFFFFFFFFFF, is this expected? Or do you want it
>>>> to overflow?
>>>> ++ pc |= mask;
>>>>
>>>> It probably has the same result, but the "return 0UL" should be more
>>>> readable. Please see kernel code:
>>>> vmcoreinfo_append_str("NUMBER(KERNELPACMASK)=0x%llx\n",
>>>>
>>>> system_supports_address_auth() ?
>>>>
>>>> ptrauth_kernel_pac_mask() : 0);
>>>>
>>>>
>>>> BTW: I cannot apply your patch with git command, and ran into some
>>>> issues, probably it is a coding issue.
>>>>
>>>> Thanks
>>>> Lianbo
>>>>
>>>>
>>>>> +#endif /* !ARM64 */
>>>>> +}
>>>>> --
>>>>> 2.34.1
>>>>>
>>>>> Thanks,
>>>>> Guanyou
>>>>>
>>>>
--
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