Hello,
> Hi all,
>
> I am a new comer to this mailing list ,
> I am happy to join this community .
>
You should send this to arm ML.
Also I believe most of people don't enable CONFIG_OABI_COMPAT, that's why they
don't hit the bug.
Matthieu
> I have a bug reported from our android phones which is caused by the system
> call .
> It seems like kernel bugs from my view .
>
> Crash in file arch\arm\kernel\ entry-common.S
>
> /***************************************************************/
>
> ENTRY(vector_swi)
> sub sp, sp, #S_FRAME_SIZE
> stmia sp, {r0 - r12} @ Calling r0 - r12
> ARM( add r8, sp, #S_PC )
> ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr
> THUMB( mov r8, sp )
> THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr
> mrs r8, spsr @ called from non-FIQ mode, so
> ok.
> str lr, [sp, #S_PC] @ Save calling PC
> str r8, [sp, #S_PSR] @ Save CPSR
> str r0, [sp, #S_OLD_R0] @ Save OLD_R0
> zero_fp
>
> /*
> * Get the system call number.
> */
>
> #if defined(CONFIG_OABI_COMPAT)
>
> /*
> * If we have CONFIG_OABI_COMPAT then we need to look at the swi
> * value to determine if it is an EABI or an old ABI call.
> */
> #ifdef CONFIG_ARM_THUMB
> tst r8, #PSR_T_BIT
> movne r10, #0 @ no thumb OABI emulation
> ldreq r10, [lr, #-4] @ get SWI instruction
> // crash at this instruction, \
> when get SWI instruction #else
> ldr r10, [lr, #-4] @ get SWI instruction
> A710( and ip, r10, #0x0f000000 @ check for SWI
> )
> A710( teq ip, #0x0f000000
> )
> A710( bne .Larm710bug
> )
> #endif
> #ifdef CONFIG_CPU_ENDIAN_BE8
> rev r10, r10 @ little endian instruction
> #endif
>
> /*************************************************************************************
> \
> **************/
>
> Then reason why it will crash when get SWI instruction is maybe
> This page is clear to aged by kernel,
> But this MMU fault happpened in kernel,
> So the kernel do_page_fault function will not clear this page to young,
> So that will crash .
>
> It should poll this page to make it present or the fault should be handled by
> fixup \
> section , Anyway, this place should not crash by kernel .
>
> The kernel version I used is 3.4.0
> I have add the kernel log and the call stack recovered by trace32 tools
> Pls have a look at it .
>
>
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