Hey Antonio,
On Nov 16 2014 or thereabouts, Antonio Borneo wrote:
> From: Jean-Baptiste Maneyrol <jmaneyrol@xxxxxxxxxxxxxx>
>
> From: Jean-Baptiste Maneyrol <jmaneyrol@xxxxxxxxxxxxxx>
>
> Current driver uses a common buffer for reading reports either
> synchronously in i2c_hid_get_raw_report() and asynchronously in
> the interrupt handler.
> There is race condition if an interrupt arrives immediately after
> the report is received in i2c_hid_get_raw_report(); the common
> buffer is modified by the interrupt handler with the new report
> and then i2c_hid_get_raw_report() proceed using wrong data.
>
> Fix it by using a separate buffers for asynchronous reports.
>
> Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@xxxxxxxxxxxxxx>
> [Antonio Borneo: cleanup and rebase to v3.17]
> Signed-off-by: Antonio Borneo <borneo.antonio@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
For your next submission, when you want a patch to go in stable, put CC
here, but please do not CC the actual mail to stable@. Stable should receive
either mails which are already in Linus' tree, or which refer a commit
in Linus' tree in case it does not applies smoothly.
[keeping stable@ here to show them that this one should not get picked
right now]
> ---
>
> Hi Jiri, Benjamin,
>
> I think this patch should also go through linux-stable.
> Confirmation from our side is welcome.
I think the patch is definitively valuable. However, my personal taste
would go for having a new .rawbuf buffer and use it in
i2c_hid_get_raw_report(). The rationale would be that it's actually
i2c_hid_get_raw_report() which is problematic, not the generic irq
handling. Also I prefer rawbuf to irqinbuf.
I am perfectly aware that this is just bikeshedding, so if changing the
patch is too cumbersome (looks like Jean-Baptiste is involved), and if
Jiri agree, this can go into the hid tree with my reviewed-by.
I am fine having this version or the rawbuf one in stable BTW.
Cheers,
Benjamin
>
> Regards,
> Antonio
>
> drivers/hid/i2c-hid/i2c-hid.c | 17 +++++++++++------
> 1 file changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index 933bf10..7c80e96 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -136,6 +136,7 @@ struct i2c_hid {
> * register of the HID
> * descriptor. */
> unsigned int bufsize; /* i2c buffer size */
> + char *irqinbuf; /* Asynchronous Input buffer */
> char *inbuf; /* Input buffer */
> char *cmdbuf; /* Command buffer */
> char *argsbuf; /* Command arguments buffer */
> @@ -371,7 +372,7 @@ static void i2c_hid_get_input(struct i2c_hid *ihid)
> int ret, ret_size;
> int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
>
> - ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
> + ret = i2c_master_recv(ihid->client, ihid->irqinbuf, size);
> if (ret != size) {
> if (ret < 0)
> return;
> @@ -381,7 +382,7 @@ static void i2c_hid_get_input(struct i2c_hid *ihid)
> return;
> }
>
> - ret_size = ihid->inbuf[0] | ihid->inbuf[1] << 8;
> + ret_size = ihid->irqinbuf[0] | ihid->irqinbuf[1] << 8;
>
> if (!ret_size) {
> /* host or device initiated RESET completed */
> @@ -396,11 +397,11 @@ static void i2c_hid_get_input(struct i2c_hid *ihid)
> return;
> }
>
> - i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
> + i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->irqinbuf);
>
> if (test_bit(I2C_HID_STARTED, &ihid->flags))
> - hid_input_report(ihid->hid, HID_INPUT_REPORT, ihid->inbuf + 2,
> - ret_size - 2, 1);
> + hid_input_report(ihid->hid, HID_INPUT_REPORT,
> + ihid->irqinbuf + 2, ret_size - 2, 1);
>
> return;
> }
> @@ -503,9 +504,11 @@ static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
>
> static void i2c_hid_free_buffers(struct i2c_hid *ihid)
> {
> + kfree(ihid->irqinbuf);
> kfree(ihid->inbuf);
> kfree(ihid->argsbuf);
> kfree(ihid->cmdbuf);
> + ihid->irqinbuf = NULL;
> ihid->inbuf = NULL;
> ihid->cmdbuf = NULL;
> ihid->argsbuf = NULL;
> @@ -521,11 +524,13 @@ static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
> sizeof(__u16) + /* size of the report */
> report_size; /* report */
>
> + ihid->irqinbuf = kzalloc(report_size, GFP_KERNEL);
> ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
> ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
> ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
>
> - if (!ihid->inbuf || !ihid->argsbuf || !ihid->cmdbuf) {
> + if (!ihid->irqinbuf || !ihid->inbuf ||
> + !ihid->argsbuf || !ihid->cmdbuf) {
> i2c_hid_free_buffers(ihid);
> return -ENOMEM;
> }
> --
> 2.1.3
>
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