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Message-Id: <20201223021813.2791612-87-sashal@kernel.org>
Date: Tue, 22 Dec 2020 21:17:30 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Takashi Iwai <tiwai@...e.de>,
syzbot+a23a6f1215c84756577c@...kaller.appspotmail.com,
syzbot+3d367d1df1d2b67f5c19@...kaller.appspotmail.com,
Sasha Levin <sashal@...nel.org>, alsa-devel@...a-project.org
Subject: [PATCH AUTOSEL 5.4 087/130] ALSA: rawmidi: Access runtime->avail always in spinlock
From: Takashi Iwai <tiwai@...e.de>
[ Upstream commit 88a06d6fd6b369d88cec46c62db3e2604a2f50d5 ]
The runtime->avail field may be accessed concurrently while some
places refer to it without taking the runtime->lock spinlock, as
detected by KCSAN. Usually this isn't a big problem, but for
consistency and safety, we should take the spinlock at each place
referencing this field.
Reported-by: syzbot+a23a6f1215c84756577c@...kaller.appspotmail.com
Reported-by: syzbot+3d367d1df1d2b67f5c19@...kaller.appspotmail.com
Link: https://lore.kernel.org/r/20201206083527.21163-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
sound/core/rawmidi.c | 49 +++++++++++++++++++++++++++++++-------------
1 file changed, 35 insertions(+), 14 deletions(-)
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 94db4683cfaff..6a3543b8455fc 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -72,11 +72,21 @@ static inline unsigned short snd_rawmidi_file_flags(struct file *file)
}
}
-static inline int snd_rawmidi_ready(struct snd_rawmidi_substream *substream)
+static inline bool __snd_rawmidi_ready(struct snd_rawmidi_runtime *runtime)
+{
+ return runtime->avail >= runtime->avail_min;
+}
+
+static bool snd_rawmidi_ready(struct snd_rawmidi_substream *substream)
{
struct snd_rawmidi_runtime *runtime = substream->runtime;
+ unsigned long flags;
+ bool ready;
- return runtime->avail >= runtime->avail_min;
+ spin_lock_irqsave(&runtime->lock, flags);
+ ready = __snd_rawmidi_ready(runtime);
+ spin_unlock_irqrestore(&runtime->lock, flags);
+ return ready;
}
static inline int snd_rawmidi_ready_append(struct snd_rawmidi_substream *substream,
@@ -945,7 +955,7 @@ int snd_rawmidi_receive(struct snd_rawmidi_substream *substream,
if (result > 0) {
if (runtime->event)
schedule_work(&runtime->event_work);
- else if (snd_rawmidi_ready(substream))
+ else if (__snd_rawmidi_ready(runtime))
wake_up(&runtime->sleep);
}
spin_unlock_irqrestore(&runtime->lock, flags);
@@ -1024,7 +1034,7 @@ static ssize_t snd_rawmidi_read(struct file *file, char __user *buf, size_t coun
result = 0;
while (count > 0) {
spin_lock_irq(&runtime->lock);
- while (!snd_rawmidi_ready(substream)) {
+ while (!__snd_rawmidi_ready(runtime)) {
wait_queue_entry_t wait;
if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
@@ -1041,9 +1051,11 @@ static ssize_t snd_rawmidi_read(struct file *file, char __user *buf, size_t coun
return -ENODEV;
if (signal_pending(current))
return result > 0 ? result : -ERESTARTSYS;
- if (!runtime->avail)
- return result > 0 ? result : -EIO;
spin_lock_irq(&runtime->lock);
+ if (!runtime->avail) {
+ spin_unlock_irq(&runtime->lock);
+ return result > 0 ? result : -EIO;
+ }
}
spin_unlock_irq(&runtime->lock);
count1 = snd_rawmidi_kernel_read1(substream,
@@ -1181,7 +1193,7 @@ int __snd_rawmidi_transmit_ack(struct snd_rawmidi_substream *substream, int coun
runtime->avail += count;
substream->bytes += count;
if (count > 0) {
- if (runtime->drain || snd_rawmidi_ready(substream))
+ if (runtime->drain || __snd_rawmidi_ready(runtime))
wake_up(&runtime->sleep);
}
return count;
@@ -1370,9 +1382,11 @@ static ssize_t snd_rawmidi_write(struct file *file, const char __user *buf,
return -ENODEV;
if (signal_pending(current))
return result > 0 ? result : -ERESTARTSYS;
- if (!runtime->avail && !timeout)
- return result > 0 ? result : -EIO;
spin_lock_irq(&runtime->lock);
+ if (!runtime->avail && !timeout) {
+ spin_unlock_irq(&runtime->lock);
+ return result > 0 ? result : -EIO;
+ }
}
spin_unlock_irq(&runtime->lock);
count1 = snd_rawmidi_kernel_write1(substream, buf, NULL, count);
@@ -1452,6 +1466,7 @@ static void snd_rawmidi_proc_info_read(struct snd_info_entry *entry,
struct snd_rawmidi *rmidi;
struct snd_rawmidi_substream *substream;
struct snd_rawmidi_runtime *runtime;
+ unsigned long buffer_size, avail, xruns;
rmidi = entry->private_data;
snd_iprintf(buffer, "%s\n\n", rmidi->name);
@@ -1470,13 +1485,16 @@ static void snd_rawmidi_proc_info_read(struct snd_info_entry *entry,
" Owner PID : %d\n",
pid_vnr(substream->pid));
runtime = substream->runtime;
+ spin_lock_irq(&runtime->lock);
+ buffer_size = runtime->buffer_size;
+ avail = runtime->avail;
+ spin_unlock_irq(&runtime->lock);
snd_iprintf(buffer,
" Mode : %s\n"
" Buffer size : %lu\n"
" Avail : %lu\n",
runtime->oss ? "OSS compatible" : "native",
- (unsigned long) runtime->buffer_size,
- (unsigned long) runtime->avail);
+ buffer_size, avail);
}
}
}
@@ -1494,13 +1512,16 @@ static void snd_rawmidi_proc_info_read(struct snd_info_entry *entry,
" Owner PID : %d\n",
pid_vnr(substream->pid));
runtime = substream->runtime;
+ spin_lock_irq(&runtime->lock);
+ buffer_size = runtime->buffer_size;
+ avail = runtime->avail;
+ xruns = runtime->xruns;
+ spin_unlock_irq(&runtime->lock);
snd_iprintf(buffer,
" Buffer size : %lu\n"
" Avail : %lu\n"
" Overruns : %lu\n",
- (unsigned long) runtime->buffer_size,
- (unsigned long) runtime->avail,
- (unsigned long) runtime->xruns);
+ buffer_size, avail, xruns);
}
}
}
--
2.27.0
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