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 Fixes: dceec3ff7807 ("arm64: expose FAR_EL1 tag bits in siginfo") Fixes: 4291e9ee6189 ("kasan, arm64: print report from tag fault handler") Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> --- arch/arm64/mm/fault.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 3c40da479899..35d75c60e2b8 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -709,10 +709,11 @@ static int do_tag_check_fault(unsigned long far, unsigned int esr, struct pt_regs *regs) { /* - * The architecture specifies that bits 63:60 of FAR_EL1 are UNKNOWN for tag - * check faults. Mask them out now so that userspace doesn't see them. + * The architecture specifies that bits 63:60 of FAR_EL1 are UNKNOWN + * for tag check faults. Set them to corresponding bits in the untagged + * address. */ - far &= (1UL << 60) - 1; + far = (__untagged_addr(far) & ~MTE_TAG_MASK) | (far & MTE_TAG_MASK); do_bad_area(far, esr, regs); return 0; } -- 2.30.0.284.gd98b1dd5eaa7-goog
