Messages in this thread |  | | | From | Steven Cole <> | | Subject | Re: 1352 NUL bytes at the end of a page? | | Date | Mon, 17 May 2004 11:30:36 -0600 |
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On May 17, 2004, at 9:37 AM, viro@parcelfarce.linux.theplanet.co.uk wrote:
> On Mon, May 17, 2004 at 08:22:10AM -0700, Linus Torvalds wrote: >> >> >> On Mon, 17 May 2004, Theodore Ts'o wrote: >>> >>> Note though that the stdio library uses a writeable mmap to implement >>> fwrite. >> >> It does? Whee. Then I'll have to agree with Andrew - if there is a >> path >> that is more likely to have bugs, it's trying to do writes with mmap >> and >> ftruncate. >> >> Who came up with that braindead idea? Is it some crazed Mach developer >> that infiltrated the glibc development group? > > IIRC, that idiocy had been disabled by default (note that it's > inherently > broken, since truncate() between your mmap() and memcpy() will lead to > a coredump, which is not something fwrite() is allowed to do in such > situation). > > strace should show if there such mmap calls are made, anyway. Did they > show up in the traces? > >
These calls show up in an strace which I did from a non-failing system, but which has the same glibc as the failing system:
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40018000 old_mmap(NULL, 19184, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40018000 The command was the following, with the result "Nothing to pull". strace bk pull bk://linux.bkbits.net/linux-2.5
There were 52 instances of mmap2 or old_mmap in the saved script log.
Steven
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