Bug 42967 - kmalloc_node crashes when it tries to allocate memory on a node that doesn't have memory
Summary: kmalloc_node crashes when it tries to allocate memory on a node that doesn't ...
Status: NEW
Alias: None
Product: Memory Management
Classification: Unclassified
Component: NUMA/discontigmem (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: Vikram Dhillon
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2012-03-20 11:26 UTC by mario.nicolas
Modified: 2014-01-23 12:23 UTC (History)
2 users (show)

See Also:
Kernel Version: 3.1.0-7
Tree: Mainline
Regression: No


Attachments
crash log (13.92 KB, text/plain)
2012-03-20 11:27 UTC, mario.nicolas
Details

Description mario.nicolas 2012-03-20 11:26:10 UTC
Hi,

kmalloc_node crashes when it tries to allocate memory on a node that doesn't have memory.
Below is a simple kernel module that illustrates the problem:
It crashes when the core parameter is out of range (for example if we use 1 when there is memory only on node 0). The log crash is attached.
A better behaviour would be to return a NULL pointer that could be checked and handled by the module.


#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>

static char* ptr = NULL;
static int core = 0;
module_param(core, int, S_IRUSR);


static int __init mymodule_init(void)
{
    printk("Using core affinity %d\n", core);
    ptr = kmalloc_node(GFP_KERNEL, 128, core);
    printk ("My module worked! ptr = %p\n", ptr);
    return 0;
}

static void __exit mymodule_exit(void)
{
    kfree(ptr);
    printk ("Unloading my module.\n");
    return;
}

module_init(mymodule_init);
module_exit(mymodule_exit);

MODULE_LICENSE("GPL");
Comment 1 mario.nicolas 2012-03-20 11:27:15 UTC
Created attachment 72657 [details]
crash log
Comment 2 Aaron Tomlin 2013-04-22 19:29:22 UTC
(In reply to comment #1)
> Created an attachment (id=72657) [details]
> crash log

Submitted a patch [1] to assert, if nodeid > num_online_nodes()
is true, under the -debug kernel, since ____cache_alloc_node()
is a "hot code" path.

---
[1]: http://marc.info/?l=linux-mm&m=136181270727758&w=1
Comment 3 Aaron Tomlin 2014-01-23 12:23:42 UTC
(In reply to Aaron Tomlin from comment #2)
> (In reply to comment #1)
> > Created an attachment (id=72657) [details]
> > crash log
> 
> Submitted a patch [1] to assert, if nodeid > num_online_nodes()
> is true, under the -debug kernel, since ____cache_alloc_node()
> is a "hot code" path.
> 
> ---
> [1]: http://marc.info/?l=linux-mm&m=136181270727758&w=1

A patch been committed since v3.11-rc1 [1] can this BUG be marked
as closed?

---
[1]: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=14e50c6a9bc2b283bb4021026226268312ceefdd

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