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Message-Id: <20210524152333.987146891@linuxfoundation.org>
Date: Mon, 24 May 2021 17:25:30 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Takashi Iwai <tiwai@...e.de>,
Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: [PATCH 5.10 035/104] ALSA: intel8x0: Dont update period unless prepared
From: Takashi Iwai <tiwai@...e.de>
commit c1f0616124c455c5c762b6f123e40bba5df759e6 upstream.
The interrupt handler of intel8x0 calls snd_intel8x0_update() whenever
the hardware sets the corresponding status bit for each stream. This
works fine for most cases as long as the hardware behaves properly.
But when the hardware gives a wrong bit set, this leads to a zero-
division Oops, and reportedly, this seems what happened on a VM.
For fixing the crash, this patch adds a internal flag indicating that
the stream is ready to be updated, and check it (as well as the flag
being in suspended) to ignore such spurious update.
Cc: <stable@...r.kernel.org>
Reported-and-tested-by: Sergey Senozhatsky <senozhatsky@...omium.org>
Link: https://lore.kernel.org/r/s5h5yzi7uh0.wl-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
sound/pci/intel8x0.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/sound/pci/intel8x0.c
+++ b/sound/pci/intel8x0.c
@@ -354,6 +354,7 @@ struct ichdev {
unsigned int ali_slot; /* ALI DMA slot */
struct ac97_pcm *pcm;
int pcm_open_flag;
+ unsigned int prepared:1;
unsigned int suspended: 1;
};
@@ -714,6 +715,9 @@ static inline void snd_intel8x0_update(s
int status, civ, i, step;
int ack = 0;
+ if (!ichdev->prepared || ichdev->suspended)
+ return;
+
spin_lock_irqsave(&chip->reg_lock, flags);
status = igetbyte(chip, port + ichdev->roff_sr);
civ = igetbyte(chip, port + ICH_REG_OFF_CIV);
@@ -904,6 +908,7 @@ static int snd_intel8x0_hw_params(struct
if (ichdev->pcm_open_flag) {
snd_ac97_pcm_close(ichdev->pcm);
ichdev->pcm_open_flag = 0;
+ ichdev->prepared = 0;
}
err = snd_ac97_pcm_open(ichdev->pcm, params_rate(hw_params),
params_channels(hw_params),
@@ -925,6 +930,7 @@ static int snd_intel8x0_hw_free(struct s
if (ichdev->pcm_open_flag) {
snd_ac97_pcm_close(ichdev->pcm);
ichdev->pcm_open_flag = 0;
+ ichdev->prepared = 0;
}
return 0;
}
@@ -999,6 +1005,7 @@ static int snd_intel8x0_pcm_prepare(stru
ichdev->pos_shift = (runtime->sample_bits > 16) ? 2 : 1;
}
snd_intel8x0_setup_periods(chip, ichdev);
+ ichdev->prepared = 1;
return 0;
}
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