On Fri, May 7, 2021 at 4:59 AM Peter Collingbourne <pcc@xxxxxxxxxx> wrote: > > These tests deliberately access these arrays out of bounds, > which will cause the dynamic local bounds checks inserted by > CONFIG_UBSAN_LOCAL_BOUNDS to fail and panic the kernel. To avoid this > problem, access the arrays via volatile pointers, which will prevent > the compiler from being able to determine the array bounds. Thanks for tracking this down! These crashes have been puzzling me for a while. > These accesses use volatile pointers to char (char *volatile) rather > than the more conventional pointers to volatile char (volatile char *) > because we want to prevent the compiler from making inferences about > the pointer itself (i.e. its array bounds), not the data that it > refers to. > > Signed-off-by: Peter Collingbourne <pcc@xxxxxxxxxx> Tested-by: Alexander Potapenko <glider@xxxxxxxxxx> (also note you are missing the Acked-by: here that Andrey gave)
