On 01/17/2014 08:20 PM, Russell King - ARM Linux wrote:
On Fri, Jan 17, 2014 at 07:57:16PM -0500, Alan Ott wrote:
On 01/17/2014 08:46 AM, Russell King - ARM Linux wrote:
My suspicion therefore is that some other thread must have died while
holding the mmap_sem, so there's probably a kernel oops
On Mon 20-01-14 11:15:09, Michal Hocko wrote:
> On Wed 15-01-14 20:13:04, Alan Ott wrote:
> [...]
> > 2. __copy_to_user_memcpy() takes a read lock (down_read()) on
>
> This looks like a bug. copy_to_user_* shouldn't take mmap_sem at all
> Check the might_fault annotation used in generic code. Arm
On Wed 15-01-14 20:13:04, Alan Ott wrote:
[...]
> 2. __copy_to_user_memcpy() takes a read lock (down_read()) on
This looks like a bug. copy_to_user_* shouldn't take mmap_sem at all
Check the might_fault annotation used in generic code. Arm version of
copy_to_user* doesn't seem to use the annotatio
On Fri, Jan 17, 2014 at 07:57:16PM -0500, Alan Ott wrote:
> On 01/17/2014 08:46 AM, Russell King - ARM Linux wrote:
>> My suspicion therefore is that some other thread must have died while
>> holding the mmap_sem, so there's probably a kernel oops earlier...
>> that's my best guess at the moment wi
On 01/17/2014 08:46 AM, Russell King - ARM Linux wrote:
On Wed, Jan 15, 2014 at 08:13:04PM -0500, Alan Ott wrote:
So my questions are:
1. Why don't I see a full backtrace beyond the exception stack? It's the
same when dump_stack() is called manually.
No idea - it looks like you're not using fra
On Wed, Jan 15, 2014 at 08:13:04PM -0500, Alan Ott wrote:
> So my questions are:
> 1. Why don't I see a full backtrace beyond the exception stack? It's the
> same when dump_stack() is called manually.
No idea - it looks like you're not using frame pointers, but are using
the unwinder. Full back
Hello,
I have a deadlock that I'm trying to understand. The symptom is multiple
tasks trying to acquire a read lock (down_read()) on mm->mmap_sem in
do_page_fault(). I'll be right up front and say that this is a fairly
old kernel (2.6.37 TI PSP kernel) on a fairly old processor DaVinci 6446.