On 04/05/2014 09:35 AM, Rafał Miłecki wrote:
Register B43_MMIO_PSM_PHY_HDR is 16 bit one, so accessing it with 32b
functions isn't safe. On my machine it causes delayed (!) CPU exception:
Disabling lock debugging due to kernel taint
mce: [Hardware Error]: CPU 0: Machine Check Exception: 4 Bank 4:
b200000000070f0f
mce: [Hardware Error]: TSC 164083803dc
mce: [Hardware Error]: PROCESSOR 2:20fc2 TIME 1396650505 SOCKET 0 APIC 0
microcode 0
mce: [Hardware Error]: Run the above through 'mcelog --ascii'
mce: [Hardware Error]: Machine check: Processor context corrupt
Kernel panic - not syncing: Fatal machine check on current CPU
Kernel Offset: 0x0 from 0xffffffff81000000 (relocation range:
0xffffffff80000000-0xffffffff9fffffff)
Signed-off-by: Rafał Miłecki <zaj...@gmail.com>
---
John: I think this patch it worth picking for 3.15 release. This bug
causes instability and can be triggered depending on the default state
of B43_NPHY_BANDCTL register.
It doesn't cause exception immediately, so I spent few hours tracing it.
---
I agree that this is a BUG fix that should be in 3.15, *and* in all stable
versions to which it would apply.
To aid John, I suggest that a better subject would be something like "b43: Fix
machine check error due to improper access of B43_MMIO_PSM_PHY_HDR". That makes
it more obvious that a bug is being fixed. In addition, you should add a "Cc:
Stable <sta...@vger.kernel.org> [2.6.35+]".
As I rarely run an 802.11n Broadcom device, it is unlikely that I have
encountered this problem, but your evidence is convincing. Once the subject and
Cc are changed, then Acked-by: Larry Finger <larry.fin...@lwfinger.net>
Larry
_______________________________________________
b43-dev mailing list
b43-dev@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/b43-dev
