Messages in this thread | | | Subject | Re: [PATCH 1/1] iommu/vt-d: Remove unnecessary WARN_ON_ONCE() | From | Lu Baolu <> | Date | Sat, 18 Jan 2020 10:14:11 +0800 |
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Hi Joerg,
On 1/17/20 5:59 PM, Joerg Roedel wrote: > On Thu, Jan 16, 2020 at 09:52:36AM +0800, Lu Baolu wrote: >> Address field in device TLB invalidation descriptor is qualified >> by the S field. If S field is zero, a single page at page address >> specified by address [63:12] is requested to be invalidated. If S >> field is set, the least significant bit in the address field with >> value 0b (say bit N) indicates the invalidation address range. The >> spec doesn't require the address [N - 1, 0] to be cleared, hence >> remove the unnecessary WARN_ON_ONCE(). >> >> Otherwise, the caller might set "mask = MAX_AGAW_PFN_WIDTH" in order >> to invalidating all the cached mappings on an endpoint, and below >> overflow error will be triggered. >> >> [...] >> UBSAN: Undefined behaviour in drivers/iommu/dmar.c:1354:3 >> shift exponent 64 is too large for 64-bit type 'long long unsigned int' >> [...] >> >> Reported-and-tested-by: Frank <fgndev@posteo.de> >> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> > > Does this need a Fixes and/or stable tag? >
This doesn't cause any errors, just an unnecessary checking of
"0 & ((1UL << 64) - 1)"
in some cases.
> > Regards, > > Joerg
Best regards, baolu
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