| Message ID | 20230421141006.1005524-1-oswald.buddenhagen@gmx.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ALSA: emu10k1: properly assert DSP init constraints | expand |
On Fri, 21 Apr 2023 16:10:06 +0200, Oswald Buddenhagen wrote: > > If these are hit, we've already trashed kernel space. There is no > recovery from that. > > Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de> Sorry, it's a big NO-NO. BUG_ON() shouldn't be used here at all. BUG_ON() is used for the case you inevitably must stop everything immediately at this point. thanks, Takashi
On Fri, Apr 21, 2023 at 05:05:28PM +0200, Takashi Iwai wrote: >On Fri, 21 Apr 2023 16:10:06 +0200, >Oswald Buddenhagen wrote: >> >> If these are hit, we've already trashed kernel space. There is no >> recovery from that. >> >> Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de> > >Sorry, it's a big NO-NO. BUG_ON() shouldn't be used here at all. > >BUG_ON() is used for the case you inevitably must stop everything >immediately at this point. > yes, this is exactly what is intended, and i hoped that the commit message makes it clear enough why. regards
On Fri, 21 Apr 2023 17:08:50 +0200, Oswald Buddenhagen wrote: > > On Fri, Apr 21, 2023 at 05:05:28PM +0200, Takashi Iwai wrote: > > On Fri, 21 Apr 2023 16:10:06 +0200, > > Oswald Buddenhagen wrote: > >> > >> If these are hit, we've already trashed kernel space. There is no > >> recovery from that. > >> > >> Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de> > > > > Sorry, it's a big NO-NO. BUG_ON() shouldn't be used here at all. > > > > BUG_ON() is used for the case you inevitably must stop everything > > immediately at this point. > > > yes, this is exactly what is intended, and i hoped that the commit > message makes it clear enough why. Not clear at all. Please explain in more details if we really *HAVE TO* use BUG_ON() there. thanks, Takashi
diff --git a/sound/pci/emu10k1/emufx.c b/sound/pci/emu10k1/emufx.c index 6cf7c8b1de47..f6f05219f7fc 100644 --- a/sound/pci/emu10k1/emufx.c +++ b/sound/pci/emu10k1/emufx.c @@ -1773,22 +1773,19 @@ A_OP(icode, &ptr, iMAC0, A_GPR(var), A_GPR(var), A_GPR(vol), A_EXTIN(input)) * ok, set up done.. */ - if (gpr > tmp) { - snd_BUG(); - err = -EIO; - goto __err; - } + BUG_ON(gpr > tmp); + BUG_ON(nctl > SND_EMU10K1_GPR_CONTROLS); + /* clear remaining instruction memory */ while (ptr < 0x400) A_OP(icode, &ptr, 0x0f, 0xc0, 0xc0, 0xcf, 0xc0); icode->gpr_add_control_count = nctl; icode->gpr_add_controls = controls; emu->support_tlv = 1; /* support TLV */ err = snd_emu10k1_icode_poke(emu, icode, true); emu->support_tlv = 0; /* clear again */ -__err: kfree(controls); __err_ctrls: kfree(icode->gpr_map); @@ -2391,16 +2388,8 @@ static int _snd_emu10k1_init_efx(struct snd_emu10k1 *emu) } - if (gpr > tmp) { - snd_BUG(); - err = -EIO; - goto __err; - } - if (i > SND_EMU10K1_GPR_CONTROLS) { - snd_BUG(); - err = -EIO; - goto __err; - } + BUG_ON(gpr > tmp); + BUG_ON(i > SND_EMU10K1_GPR_CONTROLS); /* clear remaining instruction memory */ while (ptr < 0x200)
If these are hit, we've already trashed kernel space. There is no recovery from that. Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de> --- sound/pci/emu10k1/emufx.c | 21 +++++---------------- 1 file changed, 5 insertions(+), 16 deletions(-)