At Thu, 9 Apr 2015 23:42:15 +0200, Michael Gernoth wrote:

The functions snd_emu10k1_proc_spdif_read and snd_emu1010_fpga_read acquire the emu_lock before accessing the FPGA. The function used to access the FPGA (snd_emu1010_fpga_read) also tries to take the emu_lock which causes a deadlock. Remove the outer locking in the proc-functions (guarding only the already safe fpga read) to prevent this deadlock.

Signed-off-by: Michael Gernoth michael@gernoth.net

Oh, this is a really old bug. Thanks for spotting out. Applied now with additional fixes (removing superfluous flags variables causing compile warnings).

Takashi

---

sound/pci/emu10k1/emuproc.c | 10 ---------- 1 file changed, 10 deletions(-)

diff --git a/sound/pci/emu10k1/emuproc.c b/sound/pci/emu10k1/emuproc.c index 2ca9f2e..415d23c 100644 --- a/sound/pci/emu10k1/emuproc.c +++ b/sound/pci/emu10k1/emuproc.c @@ -245,27 +245,19 @@ static void snd_emu10k1_proc_spdif_read(struct snd_info_entry *entry, u32 rate;

if (emu->card_capabilities->emu_model) {

• spin_lock_irqsave(&emu->emu_lock, flags);
  

  snd_emu1010_fpga_read(emu, 0x38, &value);

• spin_unlock_irqrestore(&emu->emu_lock, flags);
  

  if ((value & 0x1) == 0) {

• 	spin_lock_irqsave(&emu->emu_lock, flags);
  snd_emu1010_fpga_read(emu, 0x2a, &value);
  snd_emu1010_fpga_read(emu, 0x2b, &value2);
  

• 	spin_unlock_irqrestore(&emu->emu_lock, flags);
  rate = 0x1770000 / (((value << 5) | value2)+1);	
  snd_iprintf(buffer, "ADAT Locked : %u\n", rate);
  

  } else { snd_iprintf(buffer, "ADAT Unlocked\n"); }

• spin_lock_irqsave(&emu->emu_lock, flags);
  

  snd_emu1010_fpga_read(emu, 0x20, &value);

• spin_unlock_irqrestore(&emu->emu_lock, flags);
  

  if ((value & 0x4) == 0) {

• 	spin_lock_irqsave(&emu->emu_lock, flags);
  snd_emu1010_fpga_read(emu, 0x28, &value);
  snd_emu1010_fpga_read(emu, 0x29, &value2);
  

• 	spin_unlock_irqrestore(&emu->emu_lock, flags);
  rate = 0x1770000 / (((value << 5) | value2)+1);	
  snd_iprintf(buffer, "SPDIF Locked : %d\n", rate);
  

  } else {

@@ -415,9 +407,7 @@ static void snd_emu_proc_emu1010_reg_read(struct snd_info_entry *entry, snd_iprintf(buffer, "EMU1010 Registers:\n\n");

for(i = 0; i < 0x40; i+=1) {

• spin_lock_irqsave(&emu->emu_lock, flags);
  

  snd_emu1010_fpga_read(emu, i, &value);

• spin_unlock_irqrestore(&emu->emu_lock, flags);
  

  snd_iprintf(buffer, "%02X: %08X, %02X\n", i, value, (value >> 8) & 0x7f); }

}

2.1.4

---

Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel