On Nov 28 00:03, Mark Geisert wrote: > Mark Geisert wrote: > > --- > > winsup/cygwin/fhandler_disk_file.cc | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/winsup/cygwin/fhandler_disk_file.cc > > b/winsup/cygwin/fhandler_disk_file.cc > > index 5dfcae4d9..2ead9948c 100644 > [...] > > Oops, I neglected to include an explanatory comment. Issuing simultaneous > pwrite(s) on one file descriptor from multiple threads, as one might do in a > forthcoming POSIX aio implementation, sometimes results in garbage status in > the IO_STATUS_BLOCK on return from NtWriteFile(). Zeroing beforehand made > the issue go away. > > This is mildly concerning to me because there are many other uses of > IO_STATUS_BLOCK in the Cygwin DLL that haven't seemed to have needed > initialization. > > Puzzledly,
Ok, let's start with, why did you tweak pread if you only observed a problem in pwrite? In terms of pread, we already have a very recent patch series: https://sourceware.org/git/?p=newlib-cygwin.git;a=commitdiff;h=46702f92ea49 https://sourceware.org/git/?p=newlib-cygwin.git;a=commitdiff;h=c983aa48798d https://sourceware.org/git/?p=newlib-cygwin.git;a=commitdiff;h=181fe5d2edac In this case it turned out that the problem was related to hitting EOF. I wonder if we hit a similar problem here. Two points: - Did you check the status code returned by NtWriteFile? Not all non-0 status codes fail the !NT_SUCCESS (status) test. - Do you have a simple, self-contained testcase? Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat
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