From: Arnd Bergmann arnd@arndb.de
gcc gets confused by the comparison of a pointer to an integer listeral, with the assumption that this is an offset from a NULL pointer and that dereferencing it is invalid:
In file included from arch/x86/boot/compressed/misc.c:18: In function ‘parse_elf’, inlined from ‘extract_kernel’ at arch/x86/boot/compressed/misc.c:442:2: arch/x86/boot/compressed/../string.h:15:23: error: ‘__builtin_memcpy’ reading 64 bytes from a region of size 0 [-Werror=stringop-overread] 15 | #define memcpy(d,s,l) __builtin_memcpy(d,s,l) | ^~~~~~~~~~~~~~~~~~~~~~~ arch/x86/boot/compressed/misc.c:283:9: note: in expansion of macro ‘memcpy’ 283 | memcpy(&ehdr, output, sizeof(ehdr)); | ^~~~~~
I could not find any good workaround for this, but as this is only a warning for a failure during early boot, removing the line entirely works around the warning.
This should probably get addressed in gcc instead, before 11.1 gets released.
Signed-off-by: Arnd Bergmann arnd@arndb.de --- arch/x86/boot/compressed/misc.c | 2 -- 1 file changed, 2 deletions(-)
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index 3a214cc3239f..9ada64e66cb7 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -430,8 +430,6 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap, error("Destination address too large"); #endif #ifndef CONFIG_RELOCATABLE - if ((unsigned long)output != LOAD_PHYSICAL_ADDR) - error("Destination address does not match LOAD_PHYSICAL_ADDR"); if (virt_addr != LOAD_PHYSICAL_ADDR) error("Destination virtual address changed when not relocatable"); #endif