On Tue, Jan 05 2016, Dan Carpenter wrote:
> We added a new error path to this function and we forgot to drop the
> lock.
>
> Fixes: e1e3d7ec5da3 ('usb: gadget: f_midi: pre-allocate IN requests')
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
> ---
> v2: Felipe asked for this to be fixed a different way.
>
> diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
> index fb1fe96d..7d28944 100644
> --- a/drivers/usb/gadget/function/f_midi.c
> +++ b/drivers/usb/gadget/function/f_midi.c
> @@ -1163,24 +1163,25 @@ static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f)
>
> static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
> {
> - struct f_midi *midi;
> + struct f_midi *midi = NULL;
> struct f_midi_opts *opts;
> - int status, i;
> + int status;
> + int i = 0;
>
> opts = container_of(fi, struct f_midi_opts, func_inst);
>
> mutex_lock(&opts->lock);
> /* sanity check */
> if (opts->in_ports > MAX_PORTS || opts->out_ports > MAX_PORTS) {
> - mutex_unlock(&opts->lock);
> - return ERR_PTR(-EINVAL);
> + status = -EINVAL;
> + goto setup_fail;
> }
>
> /* allocate and initialize one new instance */
> midi = kzalloc(sizeof(*midi), GFP_KERNEL);
> if (!midi) {
> - mutex_unlock(&opts->lock);
> - return ERR_PTR(-ENOMEM);
> + status = -ENOMEM;
> + goto setup_fail;
> }
>
> for (i = 0; i < opts->in_ports; i++) {
> @@ -1188,7 +1189,6 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
>
> if (!port) {
> status = -ENOMEM;
> - mutex_unlock(&opts->lock);
> goto setup_fail;
> }
>
> @@ -1202,7 +1202,6 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
> midi->id = kstrdup(opts->id, GFP_KERNEL);
> if (opts->id && !midi->id) {
> status = -ENOMEM;
> - mutex_unlock(&opts->lock);
> goto setup_fail;
> }
> midi->in_ports = opts->in_ports;
> @@ -1229,6 +1228,7 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
> return &midi->func;
>
> setup_fail:
> + mutex_unlock(&opts->lock);
> for (--i; i >= 0; i--)
> kfree(midi->in_port[i]);
> kfree(midi);
How about some refactoring first:
---- >8 ----------------------------------------------------------------
>From 81220372e4acce8f1ffee00338c24472469c1abe Mon Sep 17 00:00:00 2001
From: Michal Nazarewicz <mina86@xxxxxxxxxx>
Date: Tue, 5 Jan 2016 14:43:42 +0100
Subject: [PATCH 1/2] usb: gadget: f_midi: use flexible array member for
gmidi_in_port elements
Reduce number of allocations, simplify memory management and reduce
memory usage by stacking the gmidi_in_port elements at the end of the
f_midi structure using a flexible array.
Also, observe that gmidi_in_port::midi pointer is *never* used for any
purpose so it can be safely removed.
Signed-off-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
---
drivers/usb/gadget/function/f_midi.c | 42 ++++++++++++------------------------
1 file changed, 14 insertions(+), 28 deletions(-)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 898a570..9338625 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -55,7 +55,6 @@ static const char f_midi_longname[] = "MIDI Gadget";
* USB <- IN endpoint <- rawmidi
*/
struct gmidi_in_port {
- struct f_midi *midi;
int active;
uint8_t cable;
uint8_t state;
@@ -78,7 +77,6 @@ struct f_midi {
struct snd_rawmidi_substream *in_substream[MAX_PORTS];
struct snd_rawmidi_substream *out_substream[MAX_PORTS];
- struct gmidi_in_port *in_port[MAX_PORTS];
unsigned long out_triggered;
struct tasklet_struct tasklet;
@@ -87,6 +85,8 @@ struct f_midi {
int index;
char *id;
unsigned int buflen, qlen;
+
+ struct gmidi_in_port in_ports_array[/* in_ports */];
};
static inline struct f_midi *func_to_midi(struct usb_function *f)
@@ -529,11 +529,11 @@ static void f_midi_transmit(struct f_midi *midi, struct usb_request *req)
req->length = 0;
req->complete = f_midi_complete;
- for (i = 0; i < MAX_PORTS; i++) {
- struct gmidi_in_port *port = midi->in_port[i];
+ for (i = 0; i < midi->in_ports; i++) {
+ struct gmidi_in_port *port = midi->in_ports_array + i;
struct snd_rawmidi_substream *substream = midi->in_substream[i];
- if (!port || !port->active || !substream)
+ if (!port->active || !substream)
continue;
while (req->length + 3 < midi->buflen) {
@@ -568,12 +568,12 @@ static int f_midi_in_open(struct snd_rawmidi_substream *substream)
{
struct f_midi *midi = substream->rmidi->private_data;
- if (!midi->in_port[substream->number])
+ if (substream->number > midi->in_ports)
return -EINVAL;
VDBG(midi, "%s()\n", __func__);
midi->in_substream[substream->number] = substream;
- midi->in_port[substream->number]->state = STATE_UNKNOWN;
+ midi->in_ports_array[substream->number].state = STATE_UNKNOWN;
return 0;
}
@@ -589,11 +589,11 @@ static void f_midi_in_trigger(struct snd_rawmidi_substream *substream, int up)
{
struct f_midi *midi = substream->rmidi->private_data;
- if (!midi->in_port[substream->number])
+ if (substream->number > midi->in_ports)
return;
VDBG(midi, "%s() %d\n", __func__, up);
- midi->in_port[substream->number]->active = up;
+ midi->in_ports_array[substream->number].active = up;
if (up)
tasklet_hi_schedule(&midi->tasklet);
}
@@ -1073,8 +1073,6 @@ static void f_midi_free(struct usb_function *f)
opts = container_of(f->fi, struct f_midi_opts, func_inst);
kfree(midi->id);
mutex_lock(&opts->lock);
- for (i = opts->in_ports - 1; i >= 0; --i)
- kfree(midi->in_port[i]);
kfree(midi);
--opts->refcnt;
mutex_unlock(&opts->lock);
@@ -1115,26 +1113,16 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
}
/* allocate and initialize one new instance */
- midi = kzalloc(sizeof(*midi), GFP_KERNEL);
+ midi = kzalloc(
+ sizeof(*midi) + opts->in_ports * sizeof(*midi->in_ports_array),
+ GFP_KERNEL);
if (!midi) {
mutex_unlock(&opts->lock);
return ERR_PTR(-ENOMEM);
}
- for (i = 0; i < opts->in_ports; i++) {
- struct gmidi_in_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
-
- if (!port) {
- status = -ENOMEM;
- mutex_unlock(&opts->lock);
- goto setup_fail;
- }
-
- port->midi = midi;
- port->active = 0;
- port->cable = i;
- midi->in_port[i] = port;
- }
+ for (i = 0; i < opts->in_ports; i++)
+ midi->in_ports_array[i].cable = i;
/* set up ALSA midi devices */
midi->id = kstrdup(opts->id, GFP_KERNEL);
@@ -1161,8 +1149,6 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
return &midi->func;
setup_fail:
- for (--i; i >= 0; i--)
- kfree(midi->in_port[i]);
kfree(midi);
return ERR_PTR(status);
}
---- >8 ----------------------------------------------------------------
>From 57bbb33864f7480c15dfeea627d3589775ca2491 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Date: Tue, 5 Jan 2016 13:28:09 +0300
Subject: [PATCH 2/2] usb: gadget: f_midi: missing unlock on error path
We added a new error path to this function and we forgot to drop the
lock.
Fixes: e1e3d7ec5da3 ('usb: gadget: f_midi: pre-allocate IN requests')
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
[mina86@xxxxxxxxxx: rebased on top of refactoring patch!
Signed-off-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
---
drivers/usb/gadget/function/f_midi.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 9338625..de0bac5 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -1099,7 +1099,7 @@ static void f_midi_unbind(struct usb_configuration *c, struct usb_function *f)
static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
{
- struct f_midi *midi;
+ struct f_midi *midi = NULL;
struct f_midi_opts *opts;
int status, i;
@@ -1108,8 +1108,8 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
mutex_lock(&opts->lock);
/* sanity check */
if (opts->in_ports > MAX_PORTS || opts->out_ports > MAX_PORTS) {
- mutex_unlock(&opts->lock);
- return ERR_PTR(-EINVAL);
+ status = -EINVAL;
+ goto setup_fail;
}
/* allocate and initialize one new instance */
@@ -1117,8 +1117,8 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
sizeof(*midi) + opts->in_ports * sizeof(*midi->in_ports_array),
GFP_KERNEL);
if (!midi) {
- mutex_unlock(&opts->lock);
- return ERR_PTR(-ENOMEM);
+ status = -ENOMEM;
+ goto setup_fail;
}
for (i = 0; i < opts->in_ports; i++)
@@ -1128,7 +1128,6 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
midi->id = kstrdup(opts->id, GFP_KERNEL);
if (opts->id && !midi->id) {
status = -ENOMEM;
- mutex_unlock(&opts->lock);
goto setup_fail;
}
midi->in_ports = opts->in_ports;
@@ -1149,6 +1148,7 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
return &midi->func;
setup_fail:
+ mutex_unlock(&opts->lock);
kfree(midi);
return ERR_PTR(status);
}
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, ミハウ “mina86” ナザレヴイツ (o o)
ooo +--<mpn@xxxxxxxxxx>--<xmpp:mina86@xxxxxxxxxx>--ooO--(_)--Ooo--
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