Various notifications of type "BUG kmalloc-4096 () : Redzone
overwritten" have been observed recently in various parts of
the kernel. After some time, it has been made a relation with
the use of BTRFS filesystem.
[ 22.809700] BUG kmalloc-4096 (Tainted: GW): Redzone
overwritten
https://bugzilla.kernel.org/show_bug.cgi?id=204371
--- Comment #38 from Christophe Leroy (christophe.le...@c-s.fr) ---
Le 30/07/2019 à 20:52, bugzilla-dae...@bugzilla.kernel.org a écrit :
> https://bugzilla.kernel.org/show_bug.cgi?id=204371
>
> --- Comment #2 from Andrew Morton
Le 30/07/2019 à 20:52, bugzilla-dae...@bugzilla.kernel.org a écrit :
https://bugzilla.kernel.org/show_bug.cgi?id=204371
--- Comment #2 from Andrew Morton (a...@linux-foundation.org) ---
(switched to email. Please respond via emailed reply-to-all, not via the
bugzilla web interface).
Reply
Unlike BUG_ON(x), WARN_ON(x) uses !!(x) as the trigger
of the t(d/w)nei instruction instead of using directly the
value of x.
This leads to GCC adding unnecessary pair of addic/subfe. This was
revealed after adding a WARN_ON() on top of clear_page() in order
to detect misaligned destination:
@@
Hi,
[This is an automated email]
This commit has been processed because it contains a "Fixes:" tag,
fixing commit: 69d2480456d1 btrfs: use copy_page for copying pages instead of
memcpy.
The bot has tested the following trees: v5.2.9, v4.19.67.
v5.2.9: Build OK!
v4.19.67: Failed to apply!
The below exemples of use of WARN_ON() show that the result
is sub-optimal in regard of the capabilities of powerpc.
void test_warn1(unsigned long long a)
{
WARN_ON(a);
}
void test_warn2(unsigned long a)
{
WARN_ON(a);
}
void test_warn3(unsigned long a, unsigned long b)
{
Hi Christophe,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on linus/master]
[cannot apply to v5.3-rc4 next-20190816]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system]
url:
Nicholas Piggin writes:
> diff --git a/arch/powerpc/kernel/exceptions-64s.S
> b/arch/powerpc/kernel/exceptions-64s.S
> index eee5bef736c8..64d5ffbb07d1 100644
> --- a/arch/powerpc/kernel/exceptions-64s.S
> +++ b/arch/powerpc/kernel/exceptions-64s.S
> @@ -2286,15 +2286,6 @@
