Re: [PATCH v3 2/2] kasan, arm64: fix pointer tags in KASAN reports

On Fri, Jan 15, 2021 at 6:59 PM Catalin Marinas [off-list ref] wrote:

On Fri, Jan 15, 2021 at 06:41:53PM +0100, Andrey Konovalov wrote:

quoted

As of the "arm64: expose FAR_EL1 tag bits in siginfo" patch, the address
that is passed to report_tag_fault has pointer tags in the format of 0x0X,
while KASAN uses 0xFX format (note the difference in the top 4 bits).

Fix up the pointer tag for kernel pointers in do_tag_check_fault by
setting them to the same value as bit 55. Explicitly use __untagged_addr()
instead of untagged_addr(), as the latter doesn't affect TTBR1 addresses.

Link: https://linux-review.googlesource.com/id/I9ced973866036d8679e8f4ae325de547eb969649

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

Unless there are other comments, I'll queue this for -rc5 through the
arm64 tree (I already finalised the arm64 for-next/fixes branch for this
week).

Sounds good, thank you!

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