lkml.org 
[lkml]   [2008]   [Jun]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: BUG: mmapfile/writev spurious zero bytes (x86_64/not i386, bisected, reproducable)


On Tue, 17 Jun 2008, Bron Gondwana wrote:
>
> And I appear to have sent the one without the usage comments at the top.
> Here they are:

Very interesting. There's certainly something there.

That said, there's a distracting bug which is visible when doing an strace

lseek(4, 140333890921392, SEEK_SET) = -1 EINVAL (Invalid argument)
write(4, "\0\0\0\0", 4) = 4

which is from that

lseek(newfd, mapbase + offset + size - 8, 0);
write(newfd, (char *) &zero, 4);

where the addition of "mapbase" is insane. So that will write zeroes to
the wrong part of the file (offset 64, to be exact). And that will get
overwritten by the next write, making it all look entirely insane.

That said, that bug may be distracting, but it seems to have nothign at
all to do with the actual problem. The bug seems to happen only when the
file is not pre-paged in.

Nick?

Linus


\
 
 \ /
  Last update: 2008-06-17 19:11    [W:0.062 / U:0.724 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site