[minicoredumper] Infinite loop while executing read_remote

[John Ogness]

Hi,

On 2021-08-03, "Jos Hulzink (Ellips B.V.)" <jos.hulzink at ellips.com> wrote:
> We run into the following issue when using the minicoredumper:
> Sometimes, minicoredumper fills /var/log completely when processing a
> crashed process with the following messages:
>
>        4 Jul  9 08:54:14 TrueSort minicoredumper: recept: /etc/minicoredumper/generic.recept.json

Can you post the contents of /etc/minicoredumper/generic.recept.json? A
problem was recently reported [0] that has been verified. It is a
problem when files are specified in the "maps":"dump_by_name" section.

>        5 Jul  9 08:54:14 TrueSort minicoredumper: dump: auxv phdrs: 560 bytes @ 0x400040
>        6 Jul  9 08:54:14 TrueSort minicoredumper: read_remote failed: len=4, addr=0x2094c80, dest=0xf47c6fc, errno="Success"
>        7 Jul  9 08:54:14 TrueSort minicoredumper: read_remote failed: len=4, addr=0x2094c90, dest=0xf47c6fc, errno="Success"
>        8 Jul  9 08:54:14 TrueSort minicoredumper: read_remote failed: len=4, addr=0x2094ca0, dest=0xf47c6fc, errno="Success"
>        9 Jul  9 08:54:14 TrueSort minicoredumper: read_remote failed: len=4, addr=0x2094cb0, dest=0xf47c6fc, errno="Success"
>       10 Jul  9 08:54:14 TrueSort minicoredumper: read_remote failed: len=4, addr=0x2094cc0, dest=0xf47c6fc, errno="Success"
>       11 Jul  9 08:54:14 TrueSort minicoredumper: read_remote failed: len=4, addr=0x2094cd0, dest=0xf47c6fc, errno="Success"
> <continue until disk full>
>
> Note the increments in the addr field, and the errno="Succes" is a classic :)

If this is reproducible, it would also be helpful to turn on:

     "write_proc_info": true,

Then we can at least see from which mapping it is trying to dump.

The errno="Success" is irrelevant in this case. Failed reads are
allowed. The question is: Why is it trying to read addresses that are
not mapped to anything?

But I will also take a look at the code here and figure out what could
be happening.

John Ogness

[0] https://lists.linutronix.de/pipermail/minicoredumper/2021-July/000105.html