Messages in this thread | | | Date | Sat, 4 Mar 2000 09:34:12 +1100 | From | Richard Gooch <> | Subject | Re: [patch] updates for the pipe code |
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Manfred Spraul writes: > Richard Gooch wrote: > > > What about the problem I > > reported back on 16-FEB? It's still happening with 2.3.48. The problem > > does not occur with 2.2.14. > > > > > Hi, all. I've been noticing odd behaviour with named pipes under > > > recent 2.3.x kernels (at least since 2.3.36 and possibly before). > > > > > > If you open a FIFO with O_RDONLY and then call read(2), and then > > > another process writes to the FIFO, the read(2) call doesn't return. A > > > subsequent writer process does wake up the reader, however. > > > > > > Has anybody else noticed this behaviour? > > > > I've noticed this problem on UP and SMP systems. It doesn't always > > happen, but it *does* happen :-( > > > Hmm. > I didn't notice a bug when I rewrote the locking. > Do you have a test application? Is someone using O_NONBLOCK, which end > of the fifo is opened first?
I don't really have a test application. It's my shell scripts for synchronising my window manager and X client. The reader is cat and the writer is tcsh/echo.
No-one should be doing O_NONBLOCK. I don't really know which is starting first. Earlier in 2.3.4x I had some testcode which sometimes demonstrated the same problem, but that testcode hasn't failed yet with 2.3.48.
Not once have I seen the problem with 2.2.14.
Regards,
Richard.... Permanent: rgooch@atnf.csiro.au Current: rgooch@ras.ucalgary.ca
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