Messages in this thread | | | Date | Thu, 19 Jan 2017 08:34:25 +0100 | From | Michal Hocko <> | Subject | Re: writev error codes |
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On Thu 19-01-17 15:09:52, Michael Kerrisk wrote: > Hello Michal, > > On 19 January 2017 at 04:44, Michal Hocko <mhocko@kernel.org> wrote: > > Hi, > > we have noticed that one of the LTP tests started to fail after > > 99526912c934 ("fix iov_iter_fault_in_readable()"). The code has expected > > EINVAL while it gets EFAULT. I believe the new behavior is reasonable, > > but checking the man 2 writev, there is no mention about EFAULT, > > and other errnos for that matter, so it seems this is rather under > > documented and it can confuse users. LTP has been fixed in the meantime > > [1] but this might come unexpected to others. > > > > In principle writev as a write > > "multiplier" should be allowed all the error codes that write(2) allows, > > right? I am not sure how we should reflect that. Either c&p what we have > > in man 2 write or put a reference to it and only describe writev > > specific, if there are any (I haven't checked that). > > > > [1] https://github.com/linux-test-project/ltp/commit/db19194527060a962955a7db54a2f5710e69bec9 > > Perhaps I am misunderstanding you, but in the writev(2) page there is the text: > > ERRORS > The errors are as given for read(2) and write(2). Furthermore, > preadv(), preadv2(), pwritev(), and pwritev2() can also fail for > the same reasons as lseek(2).
This has hit right to the blind spot. Sorry about the noise!
> > And in the write(2) page, we have: > > EFAULT buf is outside your accessible address space. > > Does this not cover the case you describe?
Yes
-- Michal Hocko SUSE Labs
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