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ubsan: Fix objtool UACCESS warns

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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: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195541.906007455@infradead.org
This commit is contained in:
Peter Zijlstra 2023-01-12 20:43:56 +01:00 committed by Ingo Molnar
parent ca502fc6d9
commit f18b0d7ee8
2 changed files with 5 additions and 1 deletions
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5
lib/ubsan.c
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@ -339,9 +339,10 @@ void __ubsan_handle_load_invalid_value(void *_data, void *val)
{ {
struct invalid_value_data *data = _data; struct invalid_value_data *data = _data;
char val_str[VALUE_LENGTH]; char val_str[VALUE_LENGTH];
unsigned long ua_flags = user_access_save();
if (suppress_report(&data->location)) if (suppress_report(&data->location))
return; goto out;
ubsan_prologue(&data->location, "invalid-load"); 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); val_str, data->type->type_name);
ubsan_epilogue(); ubsan_epilogue();
out:
user_access_restore(ua_flags);
} }
EXPORT_SYMBOL(__ubsan_handle_load_invalid_value); EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);

1
tools/objtool/check.c
View File

@ -1216,6 +1216,7 @@ static const char *uaccess_safe_builtin[] = {
"__ubsan_handle_type_mismatch", "__ubsan_handle_type_mismatch",
"__ubsan_handle_type_mismatch_v1", "__ubsan_handle_type_mismatch_v1",
"__ubsan_handle_shift_out_of_bounds", "__ubsan_handle_shift_out_of_bounds",
"__ubsan_handle_load_invalid_value",
/* misc */ /* misc */
"csum_partial_copy_generic", "csum_partial_copy_generic",
"copy_mc_fragile", "copy_mc_fragile",