Re: [PATCH 4.11 097/114] serial: samsung: Add missing checks for dma_map_single failure

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, May 18, 2017 at 02:18:30PM +0200, Krzysztof Kozlowski wrote:
> On Thu, May 18, 2017 at 12:46 PM, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> > 4.11-stable review patch.  If anyone has any objections, please let me know.
> >
> > ------------------
> >
> > From: Marek Szyprowski <m.szyprowski@samsung.com>
> >
> > commit 500fcc08a32bfd54f11951ba81530775df15c474 upstream.
> >
> > This patch adds missing checks for dma_map_single() failure and proper error
> > reporting. Although this issue was harmless on ARM architecture, it is always
> > good to use the DMA mapping API in a proper way. This patch fixes the following
> > DMA API debug warning:
> >
> > WARNING: CPU: 1 PID: 3785 at lib/dma-debug.c:1171 check_unmap+0x8a0/0xf28
> > dma-pl330 121a0000.pdma: DMA-API: device driver failed to check map error[device address=0x000000006e0f9000] [size=4096 bytes] [mapped as single]
> > Modules linked in:
> > CPU: 1 PID: 3785 Comm: (agetty) Tainted: G        W       4.11.0-rc1-00137-g07ca963-dirty #59
> > Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
> > [<c011aaa4>] (unwind_backtrace) from [<c01127c0>] (show_stack+0x20/0x24)
> > [<c01127c0>] (show_stack) from [<c06ba5d8>] (dump_stack+0x84/0xa0)
> > [<c06ba5d8>] (dump_stack) from [<c0139528>] (__warn+0x14c/0x180)
> > [<c0139528>] (__warn) from [<c01395a4>] (warn_slowpath_fmt+0x48/0x50)
> > [<c01395a4>] (warn_slowpath_fmt) from [<c072a114>] (check_unmap+0x8a0/0xf28)
> > [<c072a114>] (check_unmap) from [<c072a834>] (debug_dma_unmap_page+0x98/0xc8)
> > [<c072a834>] (debug_dma_unmap_page) from [<c0803874>] (s3c24xx_serial_shutdown+0x314/0x52c)
> > [<c0803874>] (s3c24xx_serial_shutdown) from [<c07f5124>] (uart_port_shutdown+0x54/0x88)
> > [<c07f5124>] (uart_port_shutdown) from [<c07f522c>] (uart_shutdown+0xd4/0x110)
> > [<c07f522c>] (uart_shutdown) from [<c07f6a8c>] (uart_hangup+0x9c/0x208)
> > [<c07f6a8c>] (uart_hangup) from [<c07c426c>] (__tty_hangup+0x49c/0x634)
> > [<c07c426c>] (__tty_hangup) from [<c07c78ac>] (tty_ioctl+0xc88/0x16e4)
> > [<c07c78ac>] (tty_ioctl) from [<c03b5f2c>] (do_vfs_ioctl+0xc4/0xd10)
> > [<c03b5f2c>] (do_vfs_ioctl) from [<c03b6bf4>] (SyS_ioctl+0x7c/0x8c)
> > [<c03b6bf4>] (SyS_ioctl) from [<c010b4a0>] (ret_fast_syscall+0x0/0x3c)
> >
> > Reported-by: Seung-Woo Kim <sw0312.kim@samsung.com>
> > Fixes: 62c37eedb74c8 ("serial: samsung: add dma reqest/release functions")
> > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> > Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> > Reviewed-by: Shuah Khan <shuahkh@osg.samsung.com>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >
> > ---
> >  drivers/tty/serial/samsung.c |   31 ++++++++++++++++++++++++-------
> >  1 file changed, 24 insertions(+), 7 deletions(-)
> >
> > --- a/drivers/tty/serial/samsung.c
> > +++ b/drivers/tty/serial/samsung.c
> > @@ -859,7 +859,7 @@ static void s3c24xx_serial_break_ctl(str
> >  static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p)
> >  {
> >         struct s3c24xx_uart_dma *dma = p->dma;
> > -       unsigned long flags;
> > +       int ret;
> 
> This does not compile:
> http://www.krzk.eu/#/builders/5/builds/225
> It works fine in mainline because the patch 3/3 of the set was
> removing the user of the flags.
> 
> I'll send a fixup for stable.

Ah, thanks, I didn't notice that on my test builds here :(

greg k-h