linux-kernel - [BUG ?] oom with empty nodes.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:	Thu, 21 Dec 2006 16:16:08 +0900
From:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	Christoph Lameter <clameter@...r.sgi.com>, npiggin@...e.de,
	Andrew Morton <akpm@...l.org>, GOTO <y-goto@...fujitsu.com>
Subject: [BUG ?] oom with empty nodes.

On some system, there are memory-less-nodes. (IOW, cpu-only-node)
Then,there are online nodes which has no memory.

Now, below code is used to detect the context where oom happens.

===
static inline int constrained_alloc(struct zonelist *zonelist, gfp_t gfp_mask)
{
#ifdef CONFIG_NUMA
        struct zone **z;
        nodemask_t nodes = node_online_map;

        for (z = zonelist->zones; *z; z++)
                if (cpuset_zone_allowed_softwall(*z, gfp_mask))
                        node_clear(zone_to_nid(*z), nodes);
                else
                        return CONSTRAINT_CPUSET;

        if (!nodes_empty(nodes))
                return CONSTRAINT_MEMORY_POLICY;
#endif

        return CONSTRAINT_NONE;
}
==
Because the zonelist never incldues memory-less-zone, above nodemask cannot be
empty if there is a memoly-less-node, never returns CONSTRAINT_NONE.

It looks select_bad_process() and panic_on_oom is checked only when
above function returns CONSTRAINT_NONE. This means current dies every time.

Does anyone have good idea for fix this ?

-Kame


 

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/