diff mbox series

[2/2] dmaengine: fsl-edma: Fix NULL pointer exception in fsl_edma_tx_handler

Message ID 1591877861-28156-2-git-send-email-krzk@kernel.org (mailing list archive)
State Accepted
Headers show
Series [1/2] dmaengine: fsl-edma: Add lockdep assert for exported function | expand

Commit Message

Krzysztof Kozlowski June 11, 2020, 12:17 p.m. UTC 
NULL pointer exception happens occasionally on serial output initiated
by login timeout.  This was reproduced only if kernel was built with
significant debugging options and EDMA driver is used with serial
console.

    col-vf50 login: root
    Password:
    Login timed out after 60 seconds.
    Unable to handle kernel NULL pointer dereference at virtual address 00000044
    Internal error: Oops: 5 [#1] ARM
    CPU: 0 PID: 157 Comm: login Not tainted 5.7.0-next-20200610-dirty #4
    Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
      (fsl_edma_tx_handler) from [<8016eb10>] (__handle_irq_event_percpu+0x64/0x304)
      (__handle_irq_event_percpu) from [<8016eddc>] (handle_irq_event_percpu+0x2c/0x7c)
      (handle_irq_event_percpu) from [<8016ee64>] (handle_irq_event+0x38/0x5c)
      (handle_irq_event) from [<801729e4>] (handle_fasteoi_irq+0xa4/0x160)
      (handle_fasteoi_irq) from [<8016ddcc>] (generic_handle_irq+0x34/0x44)
      (generic_handle_irq) from [<8016e40c>] (__handle_domain_irq+0x54/0xa8)
      (__handle_domain_irq) from [<80508bc8>] (gic_handle_irq+0x4c/0x80)
      (gic_handle_irq) from [<80100af0>] (__irq_svc+0x70/0x98)
    Exception stack(0x8459fe80 to 0x8459fec8)
    fe80: 72286b00 e3359f64 00000001 0000412d a0070013 85c98840 85c98840 a0070013
    fea0: 8054e0d4 00000000 00000002 00000000 00000002 8459fed0 8081fbe8 8081fbec
    fec0: 60070013 ffffffff
      (__irq_svc) from [<8081fbec>] (_raw_spin_unlock_irqrestore+0x30/0x58)
      (_raw_spin_unlock_irqrestore) from [<8056cb48>] (uart_flush_buffer+0x88/0xf8)
      (uart_flush_buffer) from [<80554e60>] (tty_ldisc_hangup+0x38/0x1ac)
      (tty_ldisc_hangup) from [<8054c7f4>] (__tty_hangup+0x158/0x2bc)
      (__tty_hangup) from [<80557b90>] (disassociate_ctty.part.1+0x30/0x23c)
      (disassociate_ctty.part.1) from [<8011fc18>] (do_exit+0x580/0xba0)
      (do_exit) from [<801214f8>] (do_group_exit+0x3c/0xb4)
      (do_group_exit) from [<80121580>] (__wake_up_parent+0x0/0x14)

Issue looks like race condition between interrupt handler fsl_edma_tx_handler()
(called as result of fsl_edma_xfer_desc()) and terminating the transfer with
fsl_edma_terminate_all().

The fsl_edma_tx_handler() handles interrupt for a transfer with already freed
edesc and idle==true.

Fixes: d6be34fbd39b ("dma: Add Freescale eDMA engine driver support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
---
 drivers/dma/fsl-edma.c | 7 +++++++
 1 file changed, 7 insertions(+)

Comments

Robin Gong June 11, 2020, 1:04 p.m. UTC | #1 
On 2020/06/11 20:18 Krzysztof Kozlowski <krzk@kernel.org> wrote:
> 
> NULL pointer exception happens occasionally on serial output initiated by login
> timeout.  This was reproduced only if kernel was built with significant
> debugging options and EDMA driver is used with serial console.
> 
>     col-vf50 login: root
>     Password:
>     Login timed out after 60 seconds.
>     Unable to handle kernel NULL pointer dereference at virtual address
> 00000044
>     Internal error: Oops: 5 [#1] ARM
>     CPU: 0 PID: 157 Comm: login Not tainted 5.7.0-next-20200610-dirty #4
>     Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
>       (fsl_edma_tx_handler) from [<8016eb10>]
> (__handle_irq_event_percpu+0x64/0x304)
>       (__handle_irq_event_percpu) from [<8016eddc>]
> (handle_irq_event_percpu+0x2c/0x7c)
>       (handle_irq_event_percpu) from [<8016ee64>]
> (handle_irq_event+0x38/0x5c)
>       (handle_irq_event) from [<801729e4>]
> (handle_fasteoi_irq+0xa4/0x160)
>       (handle_fasteoi_irq) from [<8016ddcc>]
> (generic_handle_irq+0x34/0x44)
>       (generic_handle_irq) from [<8016e40c>]
> (__handle_domain_irq+0x54/0xa8)
>       (__handle_domain_irq) from [<80508bc8>] (gic_handle_irq+0x4c/0x80)
>       (gic_handle_irq) from [<80100af0>] (__irq_svc+0x70/0x98)
>     Exception stack(0x8459fe80 to 0x8459fec8)
>     fe80: 72286b00 e3359f64 00000001 0000412d a0070013 85c98840
> 85c98840 a0070013
>     fea0: 8054e0d4 00000000 00000002 00000000 00000002 8459fed0
> 8081fbe8 8081fbec
>     fec0: 60070013 ffffffff
>       (__irq_svc) from [<8081fbec>]
> (_raw_spin_unlock_irqrestore+0x30/0x58)
>       (_raw_spin_unlock_irqrestore) from [<8056cb48>]
> (uart_flush_buffer+0x88/0xf8)
>       (uart_flush_buffer) from [<80554e60>] (tty_ldisc_hangup+0x38/0x1ac)
>       (tty_ldisc_hangup) from [<8054c7f4>] (__tty_hangup+0x158/0x2bc)
>       (__tty_hangup) from [<80557b90>]
> (disassociate_ctty.part.1+0x30/0x23c)
>       (disassociate_ctty.part.1) from [<8011fc18>] (do_exit+0x580/0xba0)
>       (do_exit) from [<801214f8>] (do_group_exit+0x3c/0xb4)
>       (do_group_exit) from [<80121580>] (__wake_up_parent+0x0/0x14)
> 
> Issue looks like race condition between interrupt handler fsl_edma_tx_handler()
> (called as result of fsl_edma_xfer_desc()) and terminating the transfer with
> fsl_edma_terminate_all().
> 
> The fsl_edma_tx_handler() handles interrupt for a transfer with already freed
> edesc and idle==true.
> 
> Fixes: d6be34fbd39b ("dma: Add Freescale eDMA engine driver support")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> ---
>  drivers/dma/fsl-edma.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c index
> eff7ebd8cf35..90bb72af306c 100644
> --- a/drivers/dma/fsl-edma.c
> +++ b/drivers/dma/fsl-edma.c
> @@ -45,6 +45,13 @@ static irqreturn_t fsl_edma_tx_handler(int irq, void
> *dev_id)
>  			fsl_chan = &fsl_edma->chans[ch];
> 
>  			spin_lock(&fsl_chan->vchan.lock);
> +
> +			if (!fsl_chan->edesc) {
Would you like fix the same potential issue in mcf_edma_tx_handler()
of mcf-edma.c? 
> +				/* terminate_all called before */
> +				spin_unlock(&fsl_chan->vchan.lock);
> +				continue;
> +			}
> +
>  			if (!fsl_chan->edesc->iscyclic) {
>  				list_del(&fsl_chan->edesc->vdesc.node);
>  				vchan_cookie_complete(&fsl_chan->edesc->vdesc);
> --
> 2.7.4
Krzysztof Kozlowski June 11, 2020, 1:10 p.m. UTC | #2 
On Thu, Jun 11, 2020 at 01:04:43PM +0000, Robin Gong wrote:
> On 2020/06/11 20:18 Krzysztof Kozlowski <krzk@kernel.org> wrote:
> > 
> > NULL pointer exception happens occasionally on serial output initiated by login
> > timeout.  This was reproduced only if kernel was built with significant
> > debugging options and EDMA driver is used with serial console.
> > 
> >     col-vf50 login: root
> >     Password:
> >     Login timed out after 60 seconds.
> >     Unable to handle kernel NULL pointer dereference at virtual address
> > 00000044
> >     Internal error: Oops: 5 [#1] ARM
> >     CPU: 0 PID: 157 Comm: login Not tainted 5.7.0-next-20200610-dirty #4
> >     Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
> >       (fsl_edma_tx_handler) from [<8016eb10>]
> > (__handle_irq_event_percpu+0x64/0x304)
> >       (__handle_irq_event_percpu) from [<8016eddc>]
> > (handle_irq_event_percpu+0x2c/0x7c)
> >       (handle_irq_event_percpu) from [<8016ee64>]
> > (handle_irq_event+0x38/0x5c)
> >       (handle_irq_event) from [<801729e4>]
> > (handle_fasteoi_irq+0xa4/0x160)
> >       (handle_fasteoi_irq) from [<8016ddcc>]
> > (generic_handle_irq+0x34/0x44)
> >       (generic_handle_irq) from [<8016e40c>]
> > (__handle_domain_irq+0x54/0xa8)
> >       (__handle_domain_irq) from [<80508bc8>] (gic_handle_irq+0x4c/0x80)
> >       (gic_handle_irq) from [<80100af0>] (__irq_svc+0x70/0x98)
> >     Exception stack(0x8459fe80 to 0x8459fec8)
> >     fe80: 72286b00 e3359f64 00000001 0000412d a0070013 85c98840
> > 85c98840 a0070013
> >     fea0: 8054e0d4 00000000 00000002 00000000 00000002 8459fed0
> > 8081fbe8 8081fbec
> >     fec0: 60070013 ffffffff
> >       (__irq_svc) from [<8081fbec>]
> > (_raw_spin_unlock_irqrestore+0x30/0x58)
> >       (_raw_spin_unlock_irqrestore) from [<8056cb48>]
> > (uart_flush_buffer+0x88/0xf8)
> >       (uart_flush_buffer) from [<80554e60>] (tty_ldisc_hangup+0x38/0x1ac)
> >       (tty_ldisc_hangup) from [<8054c7f4>] (__tty_hangup+0x158/0x2bc)
> >       (__tty_hangup) from [<80557b90>]
> > (disassociate_ctty.part.1+0x30/0x23c)
> >       (disassociate_ctty.part.1) from [<8011fc18>] (do_exit+0x580/0xba0)
> >       (do_exit) from [<801214f8>] (do_group_exit+0x3c/0xb4)
> >       (do_group_exit) from [<80121580>] (__wake_up_parent+0x0/0x14)
> > 
> > Issue looks like race condition between interrupt handler fsl_edma_tx_handler()
> > (called as result of fsl_edma_xfer_desc()) and terminating the transfer with
> > fsl_edma_terminate_all().
> > 
> > The fsl_edma_tx_handler() handles interrupt for a transfer with already freed
> > edesc and idle==true.
> > 
> > Fixes: d6be34fbd39b ("dma: Add Freescale eDMA engine driver support")
> > Cc: <stable@vger.kernel.org>
> > Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> > ---
> >  drivers/dma/fsl-edma.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c index
> > eff7ebd8cf35..90bb72af306c 100644
> > --- a/drivers/dma/fsl-edma.c
> > +++ b/drivers/dma/fsl-edma.c
> > @@ -45,6 +45,13 @@ static irqreturn_t fsl_edma_tx_handler(int irq, void
> > *dev_id)
> >  			fsl_chan = &fsl_edma->chans[ch];
> > 
> >  			spin_lock(&fsl_chan->vchan.lock);
> > +
> > +			if (!fsl_chan->edesc) {
> Would you like fix the same potential issue in mcf_edma_tx_handler()
> of mcf-edma.c? 

Sure. I'll make another commit as it should be backported to different
kernel.

Best regards,
Krzysztof
Robin Gong June 12, 2020, 2:22 a.m. UTC | #3 
On 2020/06/11 20:18 Krzysztof Kozlowski <krzk@kernel.org> wrote:
> NULL pointer exception happens occasionally on serial output initiated by login
> timeout.  This was reproduced only if kernel was built with significant
> debugging options and EDMA driver is used with serial console.
> 
>     col-vf50 login: root
>     Password:
>     Login timed out after 60 seconds.
>     Unable to handle kernel NULL pointer dereference at virtual address
> 00000044
>     Internal error: Oops: 5 [#1] ARM
>     CPU: 0 PID: 157 Comm: login Not tainted 5.7.0-next-20200610-dirty #4
>     Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
>       (fsl_edma_tx_handler) from [<8016eb10>]
> (__handle_irq_event_percpu+0x64/0x304)
>       (__handle_irq_event_percpu) from [<8016eddc>]
> (handle_irq_event_percpu+0x2c/0x7c)
>       (handle_irq_event_percpu) from [<8016ee64>]
> (handle_irq_event+0x38/0x5c)
>       (handle_irq_event) from [<801729e4>]
> (handle_fasteoi_irq+0xa4/0x160)
>       (handle_fasteoi_irq) from [<8016ddcc>]
> (generic_handle_irq+0x34/0x44)
>       (generic_handle_irq) from [<8016e40c>]
> (__handle_domain_irq+0x54/0xa8)
>       (__handle_domain_irq) from [<80508bc8>] (gic_handle_irq+0x4c/0x80)
>       (gic_handle_irq) from [<80100af0>] (__irq_svc+0x70/0x98)
>     Exception stack(0x8459fe80 to 0x8459fec8)
>     fe80: 72286b00 e3359f64 00000001 0000412d a0070013 85c98840
> 85c98840 a0070013
>     fea0: 8054e0d4 00000000 00000002 00000000 00000002 8459fed0
> 8081fbe8 8081fbec
>     fec0: 60070013 ffffffff
>       (__irq_svc) from [<8081fbec>]
> (_raw_spin_unlock_irqrestore+0x30/0x58)
>       (_raw_spin_unlock_irqrestore) from [<8056cb48>]
> (uart_flush_buffer+0x88/0xf8)
>       (uart_flush_buffer) from [<80554e60>] (tty_ldisc_hangup+0x38/0x1ac)
>       (tty_ldisc_hangup) from [<8054c7f4>] (__tty_hangup+0x158/0x2bc)
>       (__tty_hangup) from [<80557b90>]
> (disassociate_ctty.part.1+0x30/0x23c)
>       (disassociate_ctty.part.1) from [<8011fc18>] (do_exit+0x580/0xba0)
>       (do_exit) from [<801214f8>] (do_group_exit+0x3c/0xb4)
>       (do_group_exit) from [<80121580>] (__wake_up_parent+0x0/0x14)
> 
> Issue looks like race condition between interrupt handler fsl_edma_tx_handler()
> (called as result of fsl_edma_xfer_desc()) and terminating the transfer with
> fsl_edma_terminate_all().
> 
> The fsl_edma_tx_handler() handles interrupt for a transfer with already freed
> edesc and idle==true.
> 
> Fixes: d6be34fbd39b ("dma: Add Freescale eDMA engine driver support")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> ---
>  drivers/dma/fsl-edma.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c index
> eff7ebd8cf35..90bb72af306c 100644
> --- a/drivers/dma/fsl-edma.c
> +++ b/drivers/dma/fsl-edma.c
> @@ -45,6 +45,13 @@ static irqreturn_t fsl_edma_tx_handler(int irq, void
> *dev_id)
>  			fsl_chan = &fsl_edma->chans[ch];
> 
>  			spin_lock(&fsl_chan->vchan.lock);
> +
> +			if (!fsl_chan->edesc) {
> +				/* terminate_all called before */
> +				spin_unlock(&fsl_chan->vchan.lock);
> +				continue;
> +			}
Reviewed-by: Robin Gong <yibin.gong@nxp.com>
> +
>  			if (!fsl_chan->edesc->iscyclic) {
>  				list_del(&fsl_chan->edesc->vdesc.node);
>  				vchan_cookie_complete(&fsl_chan->edesc->vdesc);
> --
> 2.7.4
diff mbox series

Patch

diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c
index eff7ebd8cf35..90bb72af306c 100644
--- a/drivers/dma/fsl-edma.c
+++ b/drivers/dma/fsl-edma.c
@@ -45,6 +45,13 @@  static irqreturn_t fsl_edma_tx_handler(int irq, void *dev_id)
 			fsl_chan = &fsl_edma->chans[ch];
 
 			spin_lock(&fsl_chan->vchan.lock);
+
+			if (!fsl_chan->edesc) {
+				/* terminate_all called before */
+				spin_unlock(&fsl_chan->vchan.lock);
+				continue;
+			}
+
 			if (!fsl_chan->edesc->iscyclic) {
 				list_del(&fsl_chan->edesc->vdesc.node);
 				vchan_cookie_complete(&fsl_chan->edesc->vdesc);