From: Guo Ren <guoren(a)linux.alibaba.com>
These patch_text implementations are using stop_machine_cpuslocked
infrastructure with atomic cpu_count. The original idea: When the
master CPU patch_text, the others should wait for it. But current
implementation is using the first CPU as master, which couldn't
guarantee the remaining CPUs are waiting. This patch changes the
last CPU as the master to solve the potential risk.
Fixes: 64711f9a47d4 ("xtensa: implement jump_label support")
Signed-off-by: Guo Ren <guoren(a)linux.alibaba.com>
Signed-off-by: Guo Ren <guoren(a)kernel.org>
Reviewed-by: Max Filippov <jcmvbkbc(a)gmail.com>
Reviewed-by: Masami Hiramatsu <mhiramat(a)kernel.org>
Cc: <stable(a)vger.kernel.org>
Message-Id: <20220407073323.743224-4-guoren(a)kernel.org>
Signed-off-by: Max Filippov <jcmvbkbc(a)gmail.com>
---
arch/xtensa/kernel/jump_label.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/xtensa/kernel/jump_label.c b/arch/xtensa/kernel/jump_label.c
index 0dde21e0d3de..ad1841cecdfb 100644
--- a/arch/xtensa/kernel/jump_label.c
+++ b/arch/xtensa/kernel/jump_label.c
@@ -40,7 +40,7 @@ static int patch_text_stop_machine(void *data)
{
struct patch *patch = data;
- if (atomic_inc_return(&patch->cpu_count) == 1) {
+ if (atomic_inc_return(&patch->cpu_count) == num_online_cpus()) {
local_patch_text(patch->addr, patch->data, patch->sz);
atomic_inc(&patch->cpu_count);
} else {
--
2.30.2
During the uvcg_video_pump() process, if an error occurs and
uvcg_queue_cancel() is called, the buffer queue will be cleared out, but
the current marker (queue->buf_used) of the active buffer (no longer
active) is not reset. On the next iteration of uvcg_video_pump() the
stale buf_used count will be used and the logic of min((unsigned
int)len, buf->bytesused - queue->buf_used) may incorrectly calculate a
nbytes size, causing an invalid memory access.
[80802.185460][ T315] configfs-gadget gadget: uvc: VS request completed
with status -18.
[80802.185519][ T315] configfs-gadget gadget: uvc: VS request completed
with status -18.
...
uvcg_queue_cancel() is called and the queue is cleared out, but the
marker queue->buf_used is not reset.
...
[80802.262328][ T8682] Unable to handle kernel paging request at virtual
address ffffffc03af9f000
...
...
[80802.263138][ T8682] Call trace:
[80802.263146][ T8682] __memcpy+0x12c/0x180
[80802.263155][ T8682] uvcg_video_pump+0xcc/0x1e0
[80802.263165][ T8682] process_one_work+0x2cc/0x568
[80802.263173][ T8682] worker_thread+0x28c/0x518
[80802.263181][ T8682] kthread+0x160/0x170
[80802.263188][ T8682] ret_from_fork+0x10/0x18
[80802.263198][ T8682] Code: a8c12829 a88130cb a8c130
Fixes: d692522577c0 ("usb: gadget/uvc: Port UVC webcam gadget to use videobuf2 framework")
Signed-off-by: Dan Vacura <w36195(a)motorola.com>
---
Changes in v2:
- Add Fixes tag
drivers/usb/gadget/function/uvc_queue.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/usb/gadget/function/uvc_queue.c b/drivers/usb/gadget/function/uvc_queue.c
index d852ac9e47e7..2cda982f3765 100644
--- a/drivers/usb/gadget/function/uvc_queue.c
+++ b/drivers/usb/gadget/function/uvc_queue.c
@@ -264,6 +264,8 @@ void uvcg_queue_cancel(struct uvc_video_queue *queue, int disconnect)
buf->state = UVC_BUF_STATE_ERROR;
vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_ERROR);
}
+ queue->buf_used = 0;
+
/* This must be protected by the irqlock spinlock to avoid race
* conditions between uvc_queue_buffer and the disconnection event that
* could result in an interruptible wait in uvc_dequeue_buffer. Do not
--
2.32.0