linux-kernel - Re: [BUG] ALSA: echoaudio: warning when the driver fails to probe

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Message-ID: <s5hsfqjbqk7.wl-tiwai@suse.de>
Date:   Mon, 11 Apr 2022 17:14:16 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     Zheyu Ma <zheyuma97@...il.com>
Cc:     perex@...ex.cz, tiwai@...e.com, alsa-devel@...a-project.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [BUG] ALSA: echoaudio: warning when the driver fails to probe

On Mon, 11 Apr 2022 12:34:56 +0200,
Zheyu Ma wrote:
> 
> On Mon, Apr 11, 2022 at 6:30 PM Takashi Iwai <tiwai@...e.de> wrote:
> >
> > On Mon, 11 Apr 2022 11:15:41 +0200,
> > Takashi Iwai wrote:
> > >
> > > On Mon, 11 Apr 2022 11:06:09 +0200,
> > > Takashi Iwai wrote:
> > > >
> > > > On Mon, 11 Apr 2022 10:49:53 +0200,
> > > > Zheyu Ma wrote:
> > > > >
> > > > > On Mon, Apr 11, 2022 at 3:41 PM Takashi Iwai <tiwai@...e.de> wrote:
> > > > > >
> > > > > > On Sun, 10 Apr 2022 11:13:55 +0200,
> > > > > > Zheyu Ma wrote:
> > > > > > >
> > > > > > > Hello,
> > > > > > >
> > > > > > > I found a bug in echoaudio.c.
> > > > > > > When the driver fails at the function snd_echo_create(), it should
> > > > > > > release resources requested before, otherwise we will get the
> > > > > > > following warning:
> > > > > > >
> > > > > > > [    3.262866] remove_proc_entry: removing non-empty directory
> > > > > > > 'irq/21', leaking at least 'snd_indigodj'
> > > > > > > [    3.263577] WARNING: CPU: 3 PID: 261 at fs/proc/generic.c:717
> > > > > > > remove_proc_entry+0x389/0x3f0
> > > > > > > [    3.267098] RIP: 0010:remove_proc_entry+0x389/0x3f0
> > > > > > > [    3.269976] Call Trace:
> > > > > > > [    3.269979]  <TASK>
> > > > > > > [    3.269988]  unregister_irq_proc+0x14c/0x170
> > > > > > > [    3.269997]  irq_free_descs+0x94/0xe0
> > > > > > > [    3.270004]  mp_unmap_irq+0xb6/0x100
> > > > > > > [    3.270011]  acpi_unregister_gsi_ioapic+0x27/0x40
> > > > > > > [    3.270017]  acpi_pci_irq_disable+0x1d3/0x320
> > > > > > > [    3.270025]  pci_disable_device+0x1ad/0x380
> > > > > > > [    3.270034]  pcim_release+0x566/0x6d0
> > > > > > > [    3.270046]  devres_release_all+0x1f1/0x2c0
> > > > > > > [    3.270057]  really_probe+0xe0/0x920
> > > > > >
> > > > > > Could you try the patch below?
> > > > >
> > > > > The following patch works for me, the previous warning disappears, thank you.
> > > > > But I got another error, I have no idea about it.
> > > >
> > > > OK, that's bad, it's basically the destructor order problem.
> > > > Could you try the patch below instead of the previous one?
> > >
> > > Sorry, the below one instead.
> >
> > Err, scratch this one, too.  It's a deeper problem than I thought.
> > Will post a revised patch later.
> 
> Yeah, you are right, these two patches do not work, I got the same
> error message.
> Thanks for your effort.

Here we go, a revised patch.  Basically it enforces the call of
snd_card_free() at the error path during probe.

There are a bunch of similar patterns, and we need to address them
all...


thanks,

Takashi

---
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -279,6 +279,7 @@ int snd_card_new(struct device *parent, int idx, const char *xid,
 int snd_devm_card_new(struct device *parent, int idx, const char *xid,
 		      struct module *module, size_t extra_size,
 		      struct snd_card **card_ret);
+int snd_devm_probe_or_release(struct device *dev, int ret);
 
 int snd_card_disconnect(struct snd_card *card);
 void snd_card_disconnect_sync(struct snd_card *card);
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -235,6 +235,19 @@ int snd_devm_card_new(struct device *parent, int idx, const char *xid,
 }
 EXPORT_SYMBOL_GPL(snd_devm_card_new);
 
+int snd_devm_probe_or_release(struct device *dev, int ret)
+{
+	struct snd_card *card;
+
+	if (!ret)
+		return 0;
+	card = devres_find(dev, __snd_card_release, NULL, NULL);
+	if (card)
+		snd_card_free(card);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(snd_devm_probe_or_release);
+
 static int snd_card_init(struct snd_card *card, struct device *parent,
 			 int idx, const char *xid, struct module *module,
 			 size_t extra_size)
--- a/sound/pci/echoaudio/echoaudio.c
+++ b/sound/pci/echoaudio/echoaudio.c
@@ -1970,8 +1970,8 @@ static int snd_echo_create(struct snd_card *card,
 }
 
 /* constructor */
-static int snd_echo_probe(struct pci_dev *pci,
-			  const struct pci_device_id *pci_id)
+static int __snd_echo_probe(struct pci_dev *pci,
+			    const struct pci_device_id *pci_id)
 {
 	static int dev;
 	struct snd_card *card;
@@ -2139,6 +2139,12 @@ static int snd_echo_probe(struct pci_dev *pci,
 	return 0;
 }
 
+static int snd_echo_probe(struct pci_dev *pci,
+			  const struct pci_device_id *pci_id)
+{
+	return snd_devm_probe_or_release(&pci->dev,
+					 __snd_echo_probe(pci, pci_id));
+}
 
 
 #if defined(CONFIG_PM_SLEEP)