[ Upstream commit 43deb76b19663a96ec2189d8f4eb9a9dc2d7623f ] The default aux_watermark is half the AUX area buffer size. In general, on a 64-bit architecture, the AUX area buffer size could be a bigger than fits in a 32-bit type, but the calculation does not allow for that possibility. However the aux_watermark value is recorded in a u32, so should not be more than U32_MAX either. Fix by doing the calculation in a correctly sized type, and limiting the result to U32_MAX. Fixes: d68e6799a5c8 ("perf: Cap allocation order at aux_watermark") Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240624201101.60186-7-adrian.hunter@intel.com Signed-off-by: Sasha Levin <sashal@kernel.org>