Messages in this thread | | | Subject | Re: [Patch] media: ti-vpe: cal: fix a kernel oops when unloading module | From | Tomi Valkeinen <> | Date | Wed, 4 Mar 2020 10:41:16 +0200 |
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On 04/03/2020 10:40, Tomi Valkeinen wrote: > On 03/03/2020 19:26, Benoit Parrot wrote: >> After the switch to use v4l2_async_notifier_add_subdev() and >> v4l2_async_notifier_cleanup(), unloading the ti_cal module would casue a >> kernel oops. >> >> This was root cause to the fact that v4l2_async_notifier_cleanup() tries >> to kfree the asd pointer passed into v4l2_async_notifier_add_subdev(). >> >> In our case the asd reference was from a statically allocated struct. >> So in effect v4l2_async_notifier_cleanup() was trying to free a pointer >> that was not kalloc. >> >> So here we switch to using a kzalloc struct instead of a static one. >> >> Fixes: d079f94c9046 ("media: platform: Switch to v4l2_async_notifier_add_subdev") >> >> Cc: stable@vger.kernel.org >> Signed-off-by: Benoit Parrot <bparrot@ti.com> >> --- >> drivers/media/platform/ti-vpe/cal.c | 7 ++++--- >> 1 file changed, 4 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/media/platform/ti-vpe/cal.c b/drivers/media/platform/ti-vpe/cal.c >> index 6d4cbb8782ed..18fe2cb9dd17 100644 >> --- a/drivers/media/platform/ti-vpe/cal.c >> +++ b/drivers/media/platform/ti-vpe/cal.c >> @@ -372,8 +372,6 @@ struct cal_ctx { >> struct v4l2_subdev *sensor; >> struct v4l2_fwnode_endpoint endpoint; >> - struct v4l2_async_subdev asd; >> - >> struct v4l2_fh fh; >> struct cal_dev *dev; >> struct cc_data *cc; >> @@ -2032,7 +2030,6 @@ static int of_cal_create_instance(struct cal_ctx *ctx, int inst) >> parent = pdev->dev.of_node; >> - asd = &ctx->asd; >> endpoint = &ctx->endpoint; >> ep_node = NULL; >> @@ -2040,6 +2037,10 @@ static int of_cal_create_instance(struct cal_ctx *ctx, int inst) >> sensor_node = NULL; >> ret = -EINVAL; >> + asd = kzalloc(sizeof(*asd), GFP_KERNEL); >> + if (!asd) >> + goto cleanup_exit; >> + >> ctx_dbg(3, ctx, "Scanning Port node for csi2 port: %d\n", inst); >> for (index = 0; index < CAL_NUM_CSI2_PORTS; index++) { >> port = of_get_next_port(parent, port); >> > > Thanks, this fixes the crash for me. > > It does look a bit odd that something is allocated with kzalloc, and then it's freed somewhere > inside v4l2_async_notifier_cleanup, though. But if that's how it supposed to be used, looks fine to me.
Well, sent that a few seconds too early... With this patch, I see kmemleaks.
Tomi
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