[PATCH] riscv: Fix TRACE_IRQFLAGS call points in entry.S

[Yipeng Zou]

在 2022/9/11 8:45, Guo Ren 写道:
> I think it would be fixed by GENERIC_ENTRY. You could have a try.
>
> https://lore.kernel.org/linux-riscv/20220908022506.1275799-1-guoren@kernel.org/

I test your patch and yes the WARNING was gone.

But I'm just wondering about the other stable branches, will your patch 
be merged into these branches?

> On Fri, Sep 9, 2022 at 5:46 PM Yipeng Zou<zouyipeng at huawei.com>  wrote:
>> TRACE_IRQFLAGS need trace all {Enable,Disable} hard interrupts points
>> in entry.S.
>> We miss a path(work_notifysig) that cause an WARN as shown below.
>>
>> [   50.362431] ------------[ cut here ]------------
>> [   50.363607] DEBUG_LOCKS_WARN_ON(!lockdep_hardirqs_enabled())
>> [   50.367229] WARNING: CPU: 3 PID: 74 at kernel/locking/lockdep.c:5510 check_flags+0x10a/0x1e0
>> [   50.368905] Modules linked in:
>> [   50.369440] CPU: 3 PID: 74 Comm: rcS Tainted: G
>> [   50.370225] Hardware name: riscv-virtio,qemu (DT)
>> [   50.370632] epc : check_flags+0x10a/0x1e0
>> [   50.371015]  ra : check_flags+0x10a/0x1e0
>> [   50.371751] epc : ffffffff808e2670 ra : ffffffff808e2670 sp : ff20000000c3bca0
>> [   50.372721]  gp : ffffffff817e2188 tp : ff60000002fe1800 t0 : ffffffff8162a2a8
>> [   50.373321]  t1 : 0000000000000001 t2 : 2d2d2d2d2d2d2d2d s0 : ff20000000c3bcc0
>> [   50.373903]  s1 : ffffffff817e3340 a0 : 0000000000000030 a1 : ffffffff81693fa8
>> [   50.374476]  a2 : 0000000000000010 a3 : fffffffffffffffe a4 : 083151a422b8df00
>> [   50.375039]  a5 : 083151a422b8df00 a6 : ffffffff8006891e a7 : 083151a422b8df00
>> [   50.376028]  s2 : ffffffff817e54e0 s3 : ffffffff81695070 s4 : ff600000027d7800
>> [   50.376978]  s5 : ffffffff80c22770 s6 : 0000000200000022 s7 : ffffffffffffffff
>> [   50.377779]  s8 : ffffffff82301ed0 s9 : 0000000000001000 s10: 00000000001a9905
>> [   50.378335]  s11: 000000000014f3e8 t3 : ffffffff822d714f t4 : ffffffff822d714f
>> [   50.378955]  t5 : ffffffff822d7150 t6 : ff20000000c3ba98
>> [   50.379783] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003
>> [   50.380810] [<ffffffff808e27be>] lock_is_held_type+0x78/0x14e
>> [   50.381477] [<ffffffff8003e850>] __might_resched+0x26/0x22c
>> [   50.382006] [<ffffffff8003ea92>] __might_sleep+0x3c/0x66
>> [   50.382477] [<ffffffff8002324e>] get_signal+0xaa/0x912
>> [   50.382947] [<ffffffff80005368>] do_notify_resume+0x82/0x434
>> [   50.383839] [<ffffffff80003bec>] ret_from_exception+0x0/0x10
>>
>> Fixes: 3c4697982982 ("riscv: Enable LOCKDEP_SUPPORT & fixup TRACE_IRQFLAGS_SUPPORT")
>> Signed-off-by: Yipeng Zou<zouyipeng at huawei.com>
>> ---
>>   arch/riscv/kernel/entry.S | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
>> index b9eda3fcbd6d..f4d23995a4f1 100644
>> --- a/arch/riscv/kernel/entry.S
>> +++ b/arch/riscv/kernel/entry.S
>> @@ -370,16 +370,20 @@ resume_kernel:
>>
>>   work_pending:
>>          /* Enter slow path for supplementary processing */
>> -       la ra, ret_from_exception
>>          andi s1, s0, _TIF_NEED_RESCHED
>>          bnez s1, work_resched
>>   work_notifysig:
>> +#ifdef CONFIG_TRACE_IRQFLAGS
>> +       call __trace_hardirqs_on
>> +#endif
>> +       la ra, ret_from_exception
>>          /* Handle pending signals and notify-resume requests */
>>          csrs CSR_STATUS, SR_IE /* Enable interrupts for do_notify_resume() */
>>          move a0, sp /* pt_regs */
>>          move a1, s0 /* current_thread_info->flags */
>>          tail do_notify_resume
>>   work_resched:
>> +       la ra, ret_from_exception
>>          tail schedule
>>
>>   /* Slow paths for ptrace. */
>> --
>> 2.17.1
>>
-- 
Regards,
Yipeng Zou