Re: [PATCH] seq_file: fix problem when seeking mid-record.

From: Andrew Morton
Date: Tue Aug 06 2019 - 18:42:36 EST


On Mon, 05 Aug 2019 14:26:08 +1000 NeilBrown <neilb@xxxxxxxx> wrote:

> If you use lseek or similar (e.g. pread) to access
> a location in a seq_file file that is within a record,
> rather than at a record boundary, then the first read
> will return the remainder of the record, and the second
> read will return the whole of that same record (instead
> of the next record).
> Whnn seeking to a record boundary, the next record is
> correctly returned.

ouch. I'm surprised it took this long to be noticed.

Maybe we need a seqfile-basher in tools/testing/selftests/proc or
somewhere.