Re: 2.6.37-rc7: Regression: b43: crashes in hwrng_register()

Herbert Xu
2011-01-07T03:50:03Z

On Thu, Jan 06, 2011 at 03:42:55PM +0100, Mario 'BitKoenig' Holbe wrote:
>
> holbe@ideapad ~ % gcc -o via-rng-test via-rng-test.c
> holbe@ideapad ~ % ./via-rng-test
> 0xbff09d40: 00000000
> ecx: aa55aa55 edx: ffffff03 edi: 0xbff09d40
> ecx: aa55aa55 edx: 00000003 edi: 0xbff09d48
> 0xbff09d40: 339d4525
> holbe@ideapad ~ %

Thanks, I've applied this patch:

commit 0735ac1f2551d9f9d356126aaf3b1110150918e6
Author: Herbert Xu <herbert@gondor.apana.org.au>
Date: Fri Jan 7 14:48:57 2011 +1100

hwrng: via_rng - Fix asm constraints

The inline asm to invoke xstore did not specify the constraints
correctly. In particular, dx/di should have been marked as output
registers as well as input as they're modified by xstore.

Thanks to Mario Holbe for creating this patch and testing it.

Tested-by: Mario 'BitKoenig' Holbe <Mario.Holbe@TU-Ilmenau.DE>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/char/hw_random/via-rng.c b/drivers/char/hw_random/via-rng.c
index 794aacb..7f86666 100644
--- a/drivers/char/hw_random/via-rng.c
+++ b/drivers/char/hw_random/via-rng.c
@@ -81,8 +81,7 @@ static inline u32 xstore(u32 *addr, u32 edx_in)
ts_state = irq_ts_save();

asm(".byte 0x0F,0xA7,0xC0 /* xstore %%edi (addr=%0) */"
- :"=m"(*addr), "=a"(eax_out)
- :"D"(addr), "d"(edx_in));
+ : "=m" (*addr), "=a" (eax_out), "+d" (edx_in), "+D" (addr));

irq_ts_restore(ts_state);
return eax_out;

Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt