usb_kill_urb warranties that all the handlers are finished when it
returns, but does not protect against threads that might be handling
asynchronously the urb.
For UVC, the function uvc_ctrl_status_event_async() takes care of
control changes asynchronously.
If the code is executed in the following order:
CPU 0 CPU 1
===== =====
uvc_status_complete()
uvc_status_stop()
uvc_ctrl_status_event_work()
uvc_status_start() -> FAIL
Then uvc_status_start will keep failing and this error will be shown:
<4>[ 5.540139] URB 0000000000000000 submitted while active
drivers/usb/core/urb.c:378 usb_submit_urb+0x4c3/0x528
Let's improve the current situation, by not re-submiting the urb if
we are stopping the status event. Also process the queued work
(if any) during stop.
CPU 0 CPU 1
===== =====
uvc_status_complete()
uvc_status_stop()
uvc_status_start()
uvc_ctrl_status_event_work() -> FAIL
Hopefully, with the usb layer protection this should be enough to cover
all the cases.
Cc: stable(a)vger.kernel.org
Fixes: e5225c820c05 ("media: uvcvideo: Send a control event when a Control Change interrupt arrives")
Reviewed-by: Yunke Cao <yunkec(a)chromium.org>
Signed-off-by: Ricardo Ribalda <ribalda(a)chromium.org>
---
uvc: Fix race condition on uvc
Make sure that all the async work is finished when we stop the status urb.
To: Yunke Cao <yunkec(a)chromium.org>
To: Sergey Senozhatsky <senozhatsky(a)chromium.org>
To: Max Staudt <mstaudt(a)google.com>
To: Laurent Pinchart <laurent.pinchart(a)ideasonboard.com>
To: Mauro Carvalho Chehab <mchehab(a)kernel.org>
Cc: linux-media(a)vger.kernel.org
Cc: linux-kernel(a)vger.kernel.org
---
Changes in v4:
- Replace bool with atomic_t to avoid compiler reordering
- First complete the async work and then kill the urb to avoid race (Thanks Laurent!)
- Link to v3: https://lore.kernel.org/r/20221212-uvc-race-v3-0-954efc752c9a@chromium.org
Changes in v3:
- Remove the patch for dev->status, makes more sense in another series, and makes
the zero day less nervous.
- Update reviewed-by (thanks Yunke!).
- Link to v2: https://lore.kernel.org/r/20221212-uvc-race-v2-0-54496cc3b8ab@chromium.org
Changes in v2:
- Add a patch for not kalloc dev->status
- Redo the logic mechanism, so it also works with suspend (Thanks Yunke!)
- Link to v1: https://lore.kernel.org/r/20221212-uvc-race-v1-0-c52e1783c31d@chromium.org
---
drivers/media/usb/uvc/uvc_ctrl.c | 3 +++
drivers/media/usb/uvc/uvc_status.c | 6 ++++++
drivers/media/usb/uvc/uvcvideo.h | 1 +
3 files changed, 10 insertions(+)
diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index c95a2229f4fa..1be6897a7d6d 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1442,6 +1442,9 @@ static void uvc_ctrl_status_event_work(struct work_struct *work)
uvc_ctrl_status_event(w->chain, w->ctrl, w->data);
+ if (atomic_read(&dev->flush_status))
+ return;
+
/* Resubmit the URB. */
w->urb->interval = dev->int_ep->desc.bInterval;
ret = usb_submit_urb(w->urb, GFP_KERNEL);
diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c
index 7518ffce22ed..4a95850cdc1b 100644
--- a/drivers/media/usb/uvc/uvc_status.c
+++ b/drivers/media/usb/uvc/uvc_status.c
@@ -304,10 +304,16 @@ int uvc_status_start(struct uvc_device *dev, gfp_t flags)
if (dev->int_urb == NULL)
return 0;
+ atomic_set(&dev->flush_status, 0);
return usb_submit_urb(dev->int_urb, flags);
}
void uvc_status_stop(struct uvc_device *dev)
{
+ struct uvc_ctrl_work *w = &dev->async_ctrl;
+
+ atomic_set(&dev->flush_status, 1);
+ if (cancel_work_sync(&w->work))
+ uvc_ctrl_status_event(w->chain, w->ctrl, w->data);
usb_kill_urb(dev->int_urb);
}
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index df93db259312..1274691f157f 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -560,6 +560,7 @@ struct uvc_device {
struct usb_host_endpoint *int_ep;
struct urb *int_urb;
u8 *status;
+ atomic_t flush_status;
struct input_dev *input;
char input_phys[64];
---
base-commit: 0ec5a38bf8499f403f81cb81a0e3a60887d1993c
change-id: 20221212-uvc-race-09276ea68bf8
Best regards,
--
Ricardo Ribalda <ribalda(a)chromium.org>
The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
Possible dependencies:
da522b5fe1a5 ("SUNRPC: Don't leak netobj memory when gss_read_proxy_verf() fails")
5866efa8cbfb ("SUNRPC: Fix svcauth_gss_proxy_init()")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From da522b5fe1a5f8b7c20a0023e87b52a150e53bf5 Mon Sep 17 00:00:00 2001
From: Chuck Lever <chuck.lever(a)oracle.com>
Date: Sat, 26 Nov 2022 15:55:18 -0500
Subject: [PATCH] SUNRPC: Don't leak netobj memory when gss_read_proxy_verf()
fails
Fixes: 030d794bf498 ("SUNRPC: Use gssproxy upcall for server RPCGSS authentication.")
Signed-off-by: Chuck Lever <chuck.lever(a)oracle.com>
Cc: <stable(a)vger.kernel.org>
Reviewed-by: Jeff Layton <jlayton(a)kernel.org>
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index bcd74dddbe2d..9a5db285d4ae 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -1162,18 +1162,23 @@ static int gss_read_proxy_verf(struct svc_rqst *rqstp,
return res;
inlen = svc_getnl(argv);
- if (inlen > (argv->iov_len + rqstp->rq_arg.page_len))
+ if (inlen > (argv->iov_len + rqstp->rq_arg.page_len)) {
+ kfree(in_handle->data);
return SVC_DENIED;
+ }
pages = DIV_ROUND_UP(inlen, PAGE_SIZE);
in_token->pages = kcalloc(pages, sizeof(struct page *), GFP_KERNEL);
- if (!in_token->pages)
+ if (!in_token->pages) {
+ kfree(in_handle->data);
return SVC_DENIED;
+ }
in_token->page_base = 0;
in_token->page_len = inlen;
for (i = 0; i < pages; i++) {
in_token->pages[i] = alloc_page(GFP_KERNEL);
if (!in_token->pages[i]) {
+ kfree(in_handle->data);
gss_free_in_token_pages(in_token);
return SVC_DENIED;
}
The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
Possible dependencies:
da522b5fe1a5 ("SUNRPC: Don't leak netobj memory when gss_read_proxy_verf() fails")
5866efa8cbfb ("SUNRPC: Fix svcauth_gss_proxy_init()")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From da522b5fe1a5f8b7c20a0023e87b52a150e53bf5 Mon Sep 17 00:00:00 2001
From: Chuck Lever <chuck.lever(a)oracle.com>
Date: Sat, 26 Nov 2022 15:55:18 -0500
Subject: [PATCH] SUNRPC: Don't leak netobj memory when gss_read_proxy_verf()
fails
Fixes: 030d794bf498 ("SUNRPC: Use gssproxy upcall for server RPCGSS authentication.")
Signed-off-by: Chuck Lever <chuck.lever(a)oracle.com>
Cc: <stable(a)vger.kernel.org>
Reviewed-by: Jeff Layton <jlayton(a)kernel.org>
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index bcd74dddbe2d..9a5db285d4ae 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -1162,18 +1162,23 @@ static int gss_read_proxy_verf(struct svc_rqst *rqstp,
return res;
inlen = svc_getnl(argv);
- if (inlen > (argv->iov_len + rqstp->rq_arg.page_len))
+ if (inlen > (argv->iov_len + rqstp->rq_arg.page_len)) {
+ kfree(in_handle->data);
return SVC_DENIED;
+ }
pages = DIV_ROUND_UP(inlen, PAGE_SIZE);
in_token->pages = kcalloc(pages, sizeof(struct page *), GFP_KERNEL);
- if (!in_token->pages)
+ if (!in_token->pages) {
+ kfree(in_handle->data);
return SVC_DENIED;
+ }
in_token->page_base = 0;
in_token->page_len = inlen;
for (i = 0; i < pages; i++) {
in_token->pages[i] = alloc_page(GFP_KERNEL);
if (!in_token->pages[i]) {
+ kfree(in_handle->data);
gss_free_in_token_pages(in_token);
return SVC_DENIED;
}