Re: [PATCH kernel v5 1/4] powerpc/powernv/ioda: Fix race in TCE level allocation
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From: Michael Ellerman <hidden>
Date: 2019-08-22 13:08:58
Also in:
stable
On Thu, 2019-07-18 at 05:11:36 UTC, Alexey Kardashevskiy wrote:
pnv_tce() returns a pointer to a TCE entry and originally a TCE table
would be pre-allocated. For the default case of 2GB window the table
needs only a single level and that is fine. However if more levels are
requested, it is possible to get a race when 2 threads want a pointer
to a TCE entry from the same page of TCEs.
This adds cmpxchg to handle the race. Note that once TCE is non-zero,
it cannot become zero again.
CC: stable@vger.kernel.org # v4.19+
Fixes: a68bd1267b72 ("powerpc/powernv/ioda: Allocate indirect TCE levels on demand")
Signed-off-by: Alexey Kardashevskiy <redacted>Series applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/56090a3902c80c296e822d11acdb6a101b322c52 cheers