Commit f18b0d7e authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

ubsan: Fix objtool UACCESS warns 



clang-14 allyesconfig gives:

  vmlinux.o: warning: objtool: emulator_cmpxchg_emulated+0x705: call to __ubsan_handle_load_invalid_value() with UACCESS enabled
  vmlinux.o: warning: objtool: paging64_update_accessed_dirty_bits+0x39e: call to __ubsan_handle_load_invalid_value() with UACCESS enabled
  vmlinux.o: warning: objtool: paging32_update_accessed_dirty_bits+0x390: call to __ubsan_handle_load_invalid_value() with UACCESS enabled
  vmlinux.o: warning: objtool: ept_update_accessed_dirty_bits+0x43f: call to __ubsan_handle_load_invalid_value() with UACCESS enabled

Add the required eflags save/restore and whitelist the thing.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Tested-by: default avatarTony Lindgren <tony@atomide.com>
Tested-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195541.906007455@infradead.org
parent ca502fc6

lib/ubsan.c

+4 −1
Original line number Diff line number Diff line
@@ -339,9 +339,10 @@ void __ubsan_handle_load_invalid_value(void *_data, void *val) 
{

	struct invalid_value_data *data = _data;

	char val_str[VALUE_LENGTH];

	unsigned long ua_flags = user_access_save();



	if (suppress_report(&data->location))

		return;

		goto out;



	ubsan_prologue(&data->location, "invalid-load");
@@ -351,6 +352,8 @@ void __ubsan_handle_load_invalid_value(void *_data, void *val) 
		val_str, data->type->type_name);



	ubsan_epilogue();

out:

	user_access_restore(ua_flags);

}

EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);

tools/objtool/check.c

+1 −0
Original line number Diff line number Diff line
@@ -1216,6 +1216,7 @@ static const char *uaccess_safe_builtin[] = { 
	"__ubsan_handle_type_mismatch",

	"__ubsan_handle_type_mismatch_v1",

	"__ubsan_handle_shift_out_of_bounds",

	"__ubsan_handle_load_invalid_value",

	/* misc */

	"csum_partial_copy_generic",

	"copy_mc_fragile",