On 03/17, Oleg Nesterov wrote:
>
> Ah, I didn't mean the patch makes sense because of optimization. My
> point was, we can fix the race without making this code worse (in fact
> it tries to make the code better but this is subjective).
OK, I am stupid. argv_free() passes the wrong poiinter to
On 03/17, Oleg Nesterov wrote:
Ah, I didn't mean the patch makes sense because of optimization. My
point was, we can fix the race without making this code worse (in fact
it tries to make the code better but this is subjective).
OK, I am stupid. argv_free() passes the wrong poiinter to
On 03/16, Andi Kleen wrote:
>
> On Sat, Mar 16, 2013 at 10:23:51PM +0100, Oleg Nesterov wrote:
> > >
> > > rcu strings has a helper function to copy the string for sleepy cases.
> >
> > Then you need to pre-allocate, take rcu_read_lock(), copy, and check
> > that it actually fits the pre-allocated
On 03/16, Andi Kleen wrote:
On Sat, Mar 16, 2013 at 10:23:51PM +0100, Oleg Nesterov wrote:
rcu strings has a helper function to copy the string for sleepy cases.
Then you need to pre-allocate, take rcu_read_lock(), copy, and check
that it actually fits the pre-allocated buffer. Not
On Sat, Mar 16, 2013 at 10:23:51PM +0100, Oleg Nesterov wrote:
> On 03/16, Andi Kleen wrote:
> >
> > > Perhaps rcu can be better, although a global rwsem looks simpler,
> > > I dunno.
> >
> > It's a general problem with lots of sysctls.
> > >
> > > But argv_split() or its usage should be changed
On 03/16, Andi Kleen wrote:
>
> > Perhaps rcu can be better, although a global rwsem looks simpler,
> > I dunno.
>
> It's a general problem with lots of sysctls.
> >
> > But argv_split() or its usage should be changed anyway, and GFP_KERNEL
> > won't work under rcu_read_lock().
>
> rcu strings has
> Perhaps rcu can be better, although a global rwsem looks simpler,
> I dunno.
It's a general problem with lots of sysctls.
>
> But argv_split() or its usage should be changed anyway, and GFP_KERNEL
> won't work under rcu_read_lock().
rcu strings has a helper function to copy the string for
On 03/16, Andi Kleen wrote:
>
> On Sat, Mar 16, 2013 at 09:23:27PM +0100, Oleg Nesterov wrote:
> > On 03/15, Oleg Nesterov wrote:
> > >
> > > To remind, say, argv_split(poweroff_cmd) can race with sysctl changing
> > > this
> > > string, in this case it can write to the memory after argv[] array.
On Sat, Mar 16, 2013 at 09:23:27PM +0100, Oleg Nesterov wrote:
> On 03/15, Oleg Nesterov wrote:
> >
> > To remind, say, argv_split(poweroff_cmd) can race with sysctl changing this
> > string, in this case it can write to the memory after argv[] array. We can
> > fix this, or we can rewrite
On 03/15, Oleg Nesterov wrote:
>
> To remind, say, argv_split(poweroff_cmd) can race with sysctl changing this
> string, in this case it can write to the memory after argv[] array. We can
> fix this, or we can rewrite argv_split/free:
OK, please see 1/2.
And this reminds me about set_task_comm()
On 03/15, Oleg Nesterov wrote:
To remind, say, argv_split(poweroff_cmd) can race with sysctl changing this
string, in this case it can write to the memory after argv[] array. We can
fix this, or we can rewrite argv_split/free:
OK, please see 1/2.
And this reminds me about set_task_comm()
On Sat, Mar 16, 2013 at 09:23:27PM +0100, Oleg Nesterov wrote:
On 03/15, Oleg Nesterov wrote:
To remind, say, argv_split(poweroff_cmd) can race with sysctl changing this
string, in this case it can write to the memory after argv[] array. We can
fix this, or we can rewrite argv_split/free:
On 03/16, Andi Kleen wrote:
On Sat, Mar 16, 2013 at 09:23:27PM +0100, Oleg Nesterov wrote:
On 03/15, Oleg Nesterov wrote:
To remind, say, argv_split(poweroff_cmd) can race with sysctl changing
this
string, in this case it can write to the memory after argv[] array. We can
fix
Perhaps rcu can be better, although a global rwsem looks simpler,
I dunno.
It's a general problem with lots of sysctls.
But argv_split() or its usage should be changed anyway, and GFP_KERNEL
won't work under rcu_read_lock().
rcu strings has a helper function to copy the string for sleepy
On 03/16, Andi Kleen wrote:
Perhaps rcu can be better, although a global rwsem looks simpler,
I dunno.
It's a general problem with lots of sysctls.
But argv_split() or its usage should be changed anyway, and GFP_KERNEL
won't work under rcu_read_lock().
rcu strings has a helper
On Sat, Mar 16, 2013 at 10:23:51PM +0100, Oleg Nesterov wrote:
On 03/16, Andi Kleen wrote:
Perhaps rcu can be better, although a global rwsem looks simpler,
I dunno.
It's a general problem with lots of sysctls.
But argv_split() or its usage should be changed anyway, and
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