Message ID | 20191219103401.13630-1-baijiaju1990@gmail.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | [v2] media: sti: bdisp: fix a possible sleep-in-atomic-context bug in bdisp_device_run() | expand |
Thank you! On 19/12/2019 11:34 AM, Jia-Ju Bai wrote: > The driver may sleep while holding a spinlock. > The function call path (from bottom to top) in Linux 4.19 is: > > drivers/media/platform/sti/bdisp/bdisp-hw.c, 385: > msleep in bdisp_hw_reset > drivers/media/platform/sti/bdisp/bdisp-v4l2.c, 341: > bdisp_hw_reset in bdisp_device_run > drivers/media/platform/sti/bdisp/bdisp-v4l2.c, 317: > _raw_spin_lock_irqsave in bdisp_device_run > > To fix this bug, msleep() is replaced with udelay(). > > This bug is found by a static analysis tool STCheck written by myself. > > Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Reviewed-by: Fabien Dessenne <fabien.dessenne@st.com> > --- > v2: > * Use udelay() instead of mdelay(). > Thank Fabien for good advice. > > --- > drivers/media/platform/sti/bdisp/bdisp-hw.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/media/platform/sti/bdisp/bdisp-hw.c b/drivers/media/platform/sti/bdisp/bdisp-hw.c > index 4372abbb5950..a74e9fd65238 100644 > --- a/drivers/media/platform/sti/bdisp/bdisp-hw.c > +++ b/drivers/media/platform/sti/bdisp/bdisp-hw.c > @@ -14,8 +14,8 @@ > #define MAX_SRC_WIDTH 2048 > > /* Reset & boot poll config */ > -#define POLL_RST_MAX 50 > -#define POLL_RST_DELAY_MS 20 > +#define POLL_RST_MAX 500 > +#define POLL_RST_DELAY_MS 2 > > enum bdisp_target_plan { > BDISP_RGB, > @@ -382,7 +382,7 @@ int bdisp_hw_reset(struct bdisp_dev *bdisp) > for (i = 0; i < POLL_RST_MAX; i++) { > if (readl(bdisp->regs + BLT_STA1) & BLT_STA1_IDLE) > break; > - msleep(POLL_RST_DELAY_MS); > + udelay(POLL_RST_DELAY_MS * 1000); > } > if (i == POLL_RST_MAX) > dev_err(bdisp->dev, "Reset timeout\n");
diff --git a/drivers/media/platform/sti/bdisp/bdisp-hw.c b/drivers/media/platform/sti/bdisp/bdisp-hw.c index 4372abbb5950..a74e9fd65238 100644 --- a/drivers/media/platform/sti/bdisp/bdisp-hw.c +++ b/drivers/media/platform/sti/bdisp/bdisp-hw.c @@ -14,8 +14,8 @@ #define MAX_SRC_WIDTH 2048 /* Reset & boot poll config */ -#define POLL_RST_MAX 50 -#define POLL_RST_DELAY_MS 20 +#define POLL_RST_MAX 500 +#define POLL_RST_DELAY_MS 2 enum bdisp_target_plan { BDISP_RGB, @@ -382,7 +382,7 @@ int bdisp_hw_reset(struct bdisp_dev *bdisp) for (i = 0; i < POLL_RST_MAX; i++) { if (readl(bdisp->regs + BLT_STA1) & BLT_STA1_IDLE) break; - msleep(POLL_RST_DELAY_MS); + udelay(POLL_RST_DELAY_MS * 1000); } if (i == POLL_RST_MAX) dev_err(bdisp->dev, "Reset timeout\n");
The driver may sleep while holding a spinlock. The function call path (from bottom to top) in Linux 4.19 is: drivers/media/platform/sti/bdisp/bdisp-hw.c, 385: msleep in bdisp_hw_reset drivers/media/platform/sti/bdisp/bdisp-v4l2.c, 341: bdisp_hw_reset in bdisp_device_run drivers/media/platform/sti/bdisp/bdisp-v4l2.c, 317: _raw_spin_lock_irqsave in bdisp_device_run To fix this bug, msleep() is replaced with udelay(). This bug is found by a static analysis tool STCheck written by myself. Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> --- v2: * Use udelay() instead of mdelay(). Thank Fabien for good advice. --- drivers/media/platform/sti/bdisp/bdisp-hw.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)