Re: leaked swap?

Hi,

> On 14 May 2019, at 07:50, Andriy Gapon <avg_at_freebsd.org> wrote:
> 
> On 18/03/2019 17:32, Konstantin Belousov wrote:
>> tmpfs, swap-backed (or even memory backed) md, persistent posix shared
>> memory, SysV shared memory.
> 
> In the end, it was POSIX shared memory.
> I put the system into the single-user to clean up the memory as much as possible
> and then I panic'ed it and went through dirty pages and their related objects in
> kgdb.  As far as I can tell, the memory was leaked via POSIX shared memory
> objects that were never shm_unlink-ed.  It seems that there was a misbehaving
> program that had been creating such objects and then losing track of them.  (I
> was able to identify it from names it used for the objects)
> 
> It seems that, unfortunately, there is no way to list / discover POSIX shared
> memory objects that are not opened by any process.

Losing track of shared memory objects has been a problem since SysVr2 ...

> I wrote a small gdb script to examine shm_dictionary in kgdb.  It would be nice
> to have a utility (and a kernel interface) that could do the same from userland.

... it is indeed high time it was fixed.

> -- 
> Andriy Gapon
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--
Bob Bishop
rb_at_gid.co.uk