The ubsan always report Warning just like: UBSAN: Undefined behaviour in ../include/linux/etherdevice.h:386:9 load of misaligned address ffffffc069ba0482 for type 'long unsigned int' which requires 8 byte alignment CPU: 0 PID: 901 Comm: sshd Not tainted 4.xx+ #1 Hardware name: linux,dummy-virt (DT) Call trace: [<ffffffc000093600>] dump_backtrace+0x0/0x348 [<ffffffc000093968>] show_stack+0x20/0x30 [<ffffffc001651664>] dump_stack+0x144/0x1b4 [<ffffffc0016519b0>] ubsan_epilogue+0x18/0x74 [<ffffffc001651bac>] __ubsan_handle_type_mismatch+0x1a0/0x25c [<ffffffc00125d8a0>] dev_gro_receive+0x17d8/0x1830 [<ffffffc00125d928>] napi_gro_receive+0x30/0x158 [<ffffffc000f4f93c>] virtnet_receive+0xad4/0x1fa8
The reason is that when enable the CONFIG_UBSAN_ALIGNMENT, the ubsan will report the unaligned access even if the system support it (CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y), it will produce a lot of noise in the log and cause confusion. This patch will close the detection of unaligned access when the system support unaligned access. Signed-off-by: Ding Tianhong <[email protected]> --- lib/ubsan.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/lib/ubsan.c b/lib/ubsan.c index fb0409d..0799678 100644 --- a/lib/ubsan.c +++ b/lib/ubsan.c @@ -321,9 +321,10 @@ void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, if (!ptr) handle_null_ptr_deref(data); - else if (data->alignment && !IS_ALIGNED(ptr, data->alignment)) - handle_missaligned_access(data, ptr); - else + else if (data->alignment && !IS_ALIGNED(ptr, data->alignment)) { + if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) + handle_missaligned_access(data, ptr); + } else handle_object_size_mismatch(data, ptr); } EXPORT_SYMBOL(__ubsan_handle_type_mismatch); -- 1.8.3.1
