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| author | Sebastian Siewior <[email protected]> | 2016-03-08 09:03:56 +0000 |
|---|---|---|
| committer | Michael Ellerman <[email protected]> | 2016-03-29 01:08:07 +0000 |
| commit | 08a5bb2921e490939f78f38fd0d02858bb709942 (patch) | |
| tree | 69ffd3a4d483b216da03d54daca1cfc5a28b7615 /drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | |
| parent | Linux 4.6-rc1 (diff) | |
| download | kernel-08a5bb2921e490939f78f38fd0d02858bb709942.tar.gz kernel-08a5bb2921e490939f78f38fd0d02858bb709942.zip | |
powerpc/mm: Fixup preempt underflow with huge pages
hugepd_free() used __get_cpu_var() once. Nothing ensured that the code
accessing the variable did not migrate from one CPU to another and soon
this was noticed by Tiejun Chen in 94b09d755462 ("powerpc/hugetlb:
Replace __get_cpu_var with get_cpu_var"). So we had it fixed.
Christoph Lameter was doing his __get_cpu_var() replaces and forgot
PowerPC. Then he noticed this and sent his fixed up batch again which
got applied as 69111bac42f5 ("powerpc: Replace __get_cpu_var uses").
The careful reader will noticed one little detail: get_cpu_var() got
replaced with this_cpu_ptr(). So now we have a put_cpu_var() which does
a preempt_enable() and nothing that does preempt_disable() so we
underflow the preempt counter.
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: [email protected]
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Reviewed-by: Aneesh Kumar K.V <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Diffstat (limited to 'drivers/gpu/drm/amd/amdgpu/amdgpu_object.c')
0 files changed, 0 insertions, 0 deletions