Re: [PATCH] dmaengine: tegra: crash fix observed during dma client(UART) stress testing

From: Thierry Reding
Date: Tue May 03 2016 - 11:17:50 EST


On Tue, May 03, 2016 at 02:44:49PM +0000, Shardar Mohammed wrote:
> Thanks for review. Please find my comments inline.
>
> > On 03/05/16 13:14, Shardar Shariff Md wrote:
> > > During DMA client(UART) stress testing, observed below crash:
> > >
> > > [ 167.041591] Unable to handle kernel paging request at virtual
> > > address 00100108 [ 167.048818] pgd = ffffffc0de7ee000 [ 167.052222]
> > > [00100108] *pgd=0000000000000000 [ 167.056513] Internal error: Oops:
> > > 96000045 [#1] PREEMPT SMP [ 167.084048] Modules linked in:
> > > [ 167.087126] CPU: 0 PID: 1786 Comm: uarttest Tainted: G W 3.10.33-
> > gb76f6f9 #5
> > > [ 167.095040] task: ffffffc0a5ba6ac0 ti: ffffffc094380000 task.ti:
> > > ffffffc094380000 [ 167.102529] PC is at tegra_dma_tasklet+0x50/0xf4 [
> > > 167.107148] LR is at tegra_dma_tasklet+0xc0/0xf4 [ 167.111767] pc :
> > > [<ffffffc00044acc8>] lr : [<ffffffc00044ad38>] pstate: 800001c5 [
> > > 167.119155] sp : ffffffc094383a60 [ 167.122469] x29: ffffffc094383a60
> > > x28: 0000000000000000
> >
> > This appears to be from quite an old kernel. I assume that this is still valid for
> > the latest mainline?
> [Shardar] Yes.

Please get into the habit of testing your patches against upstream
kernels. Merely testing that it applies is not enough.

All patches that are submitted for mainline inclusion must be *runtime*
tested against a mainline kernel.

Also it would be nice if you could offer steps on how to reproduce, that
way we can extend our testing to make sure we never regress.

Thierry

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