* vmalloc.c question
@ 1999-02-19 10:24 Neil Booth
1999-02-19 18:11 ` Kanoj Sarcar
1999-02-19 19:43 ` Benjamin C.R. LaHaise
0 siblings, 2 replies; 3+ messages in thread
From: Neil Booth @ 1999-02-19 10:24 UTC (permalink / raw)
To: linux-mm
I have a simple question about vmalloc.c. I'm probably missing something
obvious, but it appears to me that the list "vmlist" of the kernel's
virtual memory areas is not protected by any kind of locking mechanism,
and thus subject to races. (e.g. two CPUs trying to insert a new virtual
memory block in the same place at the same time in get_vm_area).
Or what am I missing?
Thanks,
Neil.
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: vmalloc.c question
1999-02-19 10:24 vmalloc.c question Neil Booth
@ 1999-02-19 18:11 ` Kanoj Sarcar
1999-02-19 19:43 ` Benjamin C.R. LaHaise
1 sibling, 0 replies; 3+ messages in thread
From: Kanoj Sarcar @ 1999-02-19 18:11 UTC (permalink / raw)
To: Neil Booth, linux-mm
On Feb 19, 7:24pm, Neil Booth wrote:
> Subject: vmalloc.c question
> I have a simple question about vmalloc.c. I'm probably missing something
> obvious, but it appears to me that the list "vmlist" of the kernel's
> virtual memory areas is not protected by any kind of locking mechanism,
> and thus subject to races. (e.g. two CPUs trying to insert a new virtual
> memory block in the same place at the same time in get_vm_area).
>
> Or what am I missing?
>
Actually, the ia32 specific ioremap function also calls into the
get_vm_area() function. I was assuming that the giant kernel_lock
protects the "vmlist".
Kanoj
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: vmalloc.c question
1999-02-19 10:24 vmalloc.c question Neil Booth
1999-02-19 18:11 ` Kanoj Sarcar
@ 1999-02-19 19:43 ` Benjamin C.R. LaHaise
1 sibling, 0 replies; 3+ messages in thread
From: Benjamin C.R. LaHaise @ 1999-02-19 19:43 UTC (permalink / raw)
To: Neil Booth; +Cc: linux-mm
On Fri, 19 Feb 1999, Neil Booth wrote:
> I have a simple question about vmalloc.c. I'm probably missing something
> obvious, but it appears to me that the list "vmlist" of the kernel's
> virtual memory areas is not protected by any kind of locking mechanism,
> and thus subject to races. (e.g. two CPUs trying to insert a new virtual
> memory block in the same place at the same time in get_vm_area).
That's probably because it assumes the caller holds the global kernel
lock (which is okay -- vmalloc can't be called from bottom half or irq
context safely anyways).
-ben
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1999-02-19 18:11 ` Kanoj Sarcar
1999-02-19 19:43 ` Benjamin C.R. LaHaise
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