[lkml]   [2005]   [Mar]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: no need to check for NULL before calling kfree() -fs/ext2/
On Wed, 30 Mar 2005, P Lavin wrote:

> Date: Wed, 30 Mar 2005 12:45:01 +0530
> From: P Lavin <>
> To:
> Subject: Re: no need to check for NULL before calling kfree() -fs/ext2/
> Hi,
> In my wlan driver module, i allocated some memory using kmalloc in interrupt
> context, this one failed but its not returning NULL ,

kmalloc() should always return NULL if the allocation failed.

>so i was proceeding
> further everything was going wrong... & finally the kernel crahed. Can any one
> of you tell me why this is happening ? i cannot use GFP_KERNEL because i'm
> calling this function from interrupt context & it may block. Any other

If you need to allocate memory from interrupt context you should be using
GFP_ATOMIC (or, if possible, do the allocation earlier in a different

> solution for this ?? I'm concerned abt why kmalloc is not returning null if
> its not a success ??
I have no explanation for that, are you sure that's really what's

> Is it not necessary to check for NULL before calling kfree() ??

No, it is not nessesary to check for NULL before calling kfree() since
kfree() does

void kfree (const void *objp)
if (!objp)

So, if you pass kfree() a NULL pointer it deals with it itself, you don't
need to check that explicitly before calling kfree() - that's redundant.

Jesper Juhl

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-04-06 13:31    [W:0.072 / U:9.480 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site