lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 31 Aug 2020 12:09:06 +0530 From: Vinod Koul <vkoul@...nel.org> To: Linus Torvalds <torvalds@...ux-foundation.org> Cc: Guenter Roeck <linux@...ck-us.net>, Luc Van Oostenryck <luc.vanoostenryck@...il.com>, Herbert Xu <herbert@...dor.apana.org.au>, Andrew Morton <akpm@...ux-foundation.org>, Joerg Roedel <joerg.roedel@....com>, Li Yang <leoyang.li@....com>, Zhang Wei <zw@...kernel.org>, Dan Williams <dan.j.williams@...el.com>, linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>, dma <dmaengine@...r.kernel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] fsldma: fsl_ioread64*() do not need lower_32_bits() Hi Linus, On 29-08-20, 14:20, Linus Torvalds wrote: > On Sat, Aug 29, 2020 at 1:40 PM Guenter Roeck <linux@...ck-us.net> wrote: > > > > Except for > > > > CHECK: spaces preferred around that '+' (ctx:VxV) > > #29: FILE: drivers/dma/fsldma.h:223: > > + u32 val_lo = in_be32((u32 __iomem *)addr+1); > > Added spaces. > > > I don't see anything wrong with it either, so > > > > Reviewed-by: Guenter Roeck <linux@...ck-us.net> > > > > Since I didn't see the real problem with the original code, > > I'd take that with a grain of salt, though. > > Well, honestly, the old code was so confused that just making it build > is clearly already an improvement even if everything else were to be > wrong. > > So I committed my "fix". If it turns out there's more wrong in there > and somebody tests it, we can fix it again. But now it hopefully > compiles, at least. > > My bet is that if that driver ever worked on ppc32, it will continue > to work whatever we do to that function. > > I _think_ the old code happened to - completely by mistake - get the > value right for the case of "little endian access, with dma_addr_t > being 32-bit". Because then it would still read the upper bits wrong, > but the cast to dma_addr_t would then throw those bits away. And the > lower bits would be right. > > But for big-endian accesses or for ARCH_DMA_ADDR_T_64BIT it really > looks like it always returned a completely incorrect value. > > And again - the driver may have worked even with that completely > incorrect value, since the use of it seems to be very incidental. Thank you for the fix. Acked-By: Vinod Koul <vkoul@...nel.org> > > In either case ("it didn't work before" or "it worked because the > value doesn't really matter"), I don't think I could possibly have > made things worse. > > Famous last words. I guess no one tested this on 32bits seems to have caused this. -- ~Vinod
Powered by blists - more mailing lists