| Message ID | 20150409214215.GA27140@zerfleddert.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 >
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); } }
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> --- sound/pci/emu10k1/emuproc.c | 10 ---------- 1 file changed, 10 deletions(-)