From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: perex@perex.cz, tiwai@suse.com, rfontana@redhat.com,
tglx@linutronix.de, allison@lohutok.net
Cc: alsa-devel@alsa-project.org, Jia-Ju Bai <baijiaju1990@gmail.com>,
linux-kernel@vger.kernel.org
Subject: [alsa-devel] [PATCH] ALSA: cmipci: Fix possible a data race in snd_cmipci_interrupt()
Date: Sun, 12 Jan 2020 00:30:27 +0800 [thread overview]
Message-ID: <20200111163027.27135-1-baijiaju1990@gmail.com> (raw)
The functions snd_cmipci_interrupt() and snd_cmipci_capture_trigger()
may be concurrently executed.
The function snd_cmipci_capture_trigger() calls
snd_cmipci_pcm_trigger(). In snd_cmipci_pcm_trigger(), the variable
rec->running is written with holding a spinlock cm->reg_lock. But in
snd_cmipci_interrupt(), the identical variable cm->channel[0].running
or cm->channel[1].running is read without holding this spinlock. Thus,
a possible data race may occur.
To fix this data race, in snd_cmipci_interrupt(), the variables
cm->channel[0].running and cm->channel[1].running are read with holding
the spinlock cm->reg_lock.
This data race is found by the runtime testing of our tool DILP-2.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
sound/pci/cmipci.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/sound/pci/cmipci.c b/sound/pci/cmipci.c
index dd9d62e2b633..f791152ec48f 100644
--- a/sound/pci/cmipci.c
+++ b/sound/pci/cmipci.c
@@ -1430,7 +1430,7 @@ static int snd_cmipci_capture_spdif_hw_free(struct snd_pcm_substream *subs)
static irqreturn_t snd_cmipci_interrupt(int irq, void *dev_id)
{
struct cmipci *cm = dev_id;
- unsigned int status, mask = 0;
+ unsigned int run_flag0, run_flag1, status, mask = 0;
/* fastpath out, to ease interrupt sharing */
status = snd_cmipci_read(cm, CM_REG_INT_STATUS);
@@ -1445,15 +1445,17 @@ static irqreturn_t snd_cmipci_interrupt(int irq, void *dev_id)
mask |= CM_CH1_INT_EN;
snd_cmipci_clear_bit(cm, CM_REG_INT_HLDCLR, mask);
snd_cmipci_set_bit(cm, CM_REG_INT_HLDCLR, mask);
+ run_flag0 = cm->channel[0].running;
+ run_flag1 = cm->channel[1].running;
spin_unlock(&cm->reg_lock);
if (cm->rmidi && (status & CM_UARTINT))
snd_mpu401_uart_interrupt(irq, cm->rmidi->private_data);
if (cm->pcm) {
- if ((status & CM_CHINT0) && cm->channel[0].running)
+ if ((status & CM_CHINT0) && run_flag0)
snd_pcm_period_elapsed(cm->channel[0].substream);
- if ((status & CM_CHINT1) && cm->channel[1].running)
+ if ((status & CM_CHINT1) && run_flag1)
snd_pcm_period_elapsed(cm->channel[1].substream);
}
return IRQ_HANDLED;
--
2.17.1
_______________________________________________
Alsa-devel mailing list
Alsa-devel@alsa-project.org
https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
next reply other threads:[~2020-01-11 16:32 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-11 16:30 Jia-Ju Bai [this message]
2020-01-12 8:20 ` [alsa-devel] [PATCH] ALSA: cmipci: Fix possible a data race in snd_cmipci_interrupt() Takashi Iwai
2020-01-13 8:20 ` Jia-Ju Bai
2020-01-13 8:40 ` Takashi Iwai
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200111163027.27135-1-baijiaju1990@gmail.com \
--to=baijiaju1990@gmail.com \
--cc=allison@lohutok.net \
--cc=alsa-devel@alsa-project.org \
--cc=linux-kernel@vger.kernel.org \
--cc=perex@perex.cz \
--cc=rfontana@redhat.com \
--cc=tglx@linutronix.de \
--cc=tiwai@suse.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).