forked from Minki/linux
lib/ubsan: don't serialize UBSAN report
At the moment, UBSAN report will be serialized using a spin_lock(). On RT-systems, spinlocks are turned to rt_spin_lock and may sleep. This will result to the following splat if the undefined behavior is in a context that can sleep: BUG: sleeping function called from invalid context at /src/linux/kernel/locking/rtmutex.c:968 in_atomic(): 1, irqs_disabled(): 128, pid: 3447, name: make 1 lock held by make/3447: #0: 000000009a966332 (&mm->mmap_sem){++++}, at: do_page_fault+0x140/0x4f8 irq event stamp: 6284 hardirqs last enabled at (6283): [<ffff000011326520>] _raw_spin_unlock_irqrestore+0x90/0xa0 hardirqs last disabled at (6284): [<ffff0000113262b0>] _raw_spin_lock_irqsave+0x30/0x78 softirqs last enabled at (2430): [<ffff000010088ef8>] fpsimd_restore_current_state+0x60/0xe8 softirqs last disabled at (2427): [<ffff000010088ec0>] fpsimd_restore_current_state+0x28/0xe8 Preemption disabled at: [<ffff000011324a4c>] rt_mutex_futex_unlock+0x4c/0xb0 CPU: 3 PID: 3447 Comm: make Tainted: G W 5.2.14-rt7-01890-ge6e057589653 #911 Call trace: dump_backtrace+0x0/0x148 show_stack+0x14/0x20 dump_stack+0xbc/0x104 ___might_sleep+0x154/0x210 rt_spin_lock+0x68/0xa0 ubsan_prologue+0x30/0x68 handle_overflow+0x64/0xe0 __ubsan_handle_add_overflow+0x10/0x18 __lock_acquire+0x1c28/0x2a28 lock_acquire+0xf0/0x370 _raw_spin_lock_irqsave+0x58/0x78 rt_mutex_futex_unlock+0x4c/0xb0 rt_spin_unlock+0x28/0x70 get_page_from_freelist+0x428/0x2b60 __alloc_pages_nodemask+0x174/0x1708 alloc_pages_vma+0x1ac/0x238 __handle_mm_fault+0x4ac/0x10b0 handle_mm_fault+0x1d8/0x3b0 do_page_fault+0x1c8/0x4f8 do_translation_fault+0xb8/0xe0 do_mem_abort+0x3c/0x98 el0_da+0x20/0x24 The spin_lock() will protect against multiple CPUs to output a report together, I guess to prevent them from being interleaved. However, they can still interleave with other messages (and even splat from __might_sleep). So the lock usefulness seems pretty limited. Rather than trying to accomodate RT-system by switching to a raw_spin_lock(), the lock is now completely dropped. Link: http://lkml.kernel.org/r/20190920100835.14999-1-julien.grall@arm.com Signed-off-by: Julien Grall <julien.grall@arm.com> Reported-by: Andre Przywara <andre.przywara@arm.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Julien Grall
Linus Torvalds
parent
8f6a7f96dc
commit
ce5c31db36
64
lib/ubsan.c
64
lib/ubsan.c
@ -140,25 +140,21 @@ static void val_to_string(char *str, size_t size, struct type_descriptor *type,
|
||||
}
|
||||
}
|
||||
|
||||
static DEFINE_SPINLOCK(report_lock);
|
||||
|
||||
static void ubsan_prologue(struct source_location *location,
|
||||
unsigned long *flags)
|
||||
static void ubsan_prologue(struct source_location *location)
|
||||
{
|
||||
current->in_ubsan++;
|
||||
spin_lock_irqsave(&report_lock, *flags);
|
||||
|
||||
pr_err("========================================"
|
||||
"========================================\n");
|
||||
print_source_location("UBSAN: Undefined behaviour in", location);
|
||||
}
|
||||
|
||||
static void ubsan_epilogue(unsigned long *flags)
|
||||
static void ubsan_epilogue(void)
|
||||
{
|
||||
dump_stack();
|
||||
pr_err("========================================"
|
||||
"========================================\n");
|
||||
spin_unlock_irqrestore(&report_lock, *flags);
|
||||
|
||||
current->in_ubsan--;
|
||||
}
|
||||
|
||||
@ -167,14 +163,13 @@ static void handle_overflow(struct overflow_data *data, void *lhs,
|
||||
{
|
||||
|
||||
struct type_descriptor *type = data->type;
|
||||
unsigned long flags;
|
||||
char lhs_val_str[VALUE_LENGTH];
|
||||
char rhs_val_str[VALUE_LENGTH];
|
||||
|
||||
if (suppress_report(&data->location))
|
||||
return;
|
||||
|
||||
ubsan_prologue(&data->location, &flags);
|
||||
ubsan_prologue(&data->location);
|
||||
|
||||
val_to_string(lhs_val_str, sizeof(lhs_val_str), type, lhs);
|
||||
val_to_string(rhs_val_str, sizeof(rhs_val_str), type, rhs);
|
||||
@ -186,7 +181,7 @@ static void handle_overflow(struct overflow_data *data, void *lhs,
|
||||
rhs_val_str,
|
||||
type->type_name);
|
||||
|
||||
ubsan_epilogue(&flags);
|
||||
ubsan_epilogue();
|
||||
}
|
||||
|
||||
void __ubsan_handle_add_overflow(struct overflow_data *data,
|
||||
@ -214,20 +209,19 @@ EXPORT_SYMBOL(__ubsan_handle_mul_overflow);
|
||||
void __ubsan_handle_negate_overflow(struct overflow_data *data,
|
||||
void *old_val)
|
||||
{
|
||||
unsigned long flags;
|
||||
char old_val_str[VALUE_LENGTH];
|
||||
|
||||
if (suppress_report(&data->location))
|
||||
return;
|
||||
|
||||
ubsan_prologue(&data->location, &flags);
|
||||
ubsan_prologue(&data->location);
|
||||
|
||||
val_to_string(old_val_str, sizeof(old_val_str), data->type, old_val);
|
||||
|
||||
pr_err("negation of %s cannot be represented in type %s:\n",
|
||||
old_val_str, data->type->type_name);
|
||||
|
||||
ubsan_epilogue(&flags);
|
||||
ubsan_epilogue();
|
||||
}
|
||||
EXPORT_SYMBOL(__ubsan_handle_negate_overflow);
|
||||
|
||||
@ -235,13 +229,12 @@ EXPORT_SYMBOL(__ubsan_handle_negate_overflow);
|
||||
void __ubsan_handle_divrem_overflow(struct overflow_data *data,
|
||||
void *lhs, void *rhs)
|
||||
{
|
||||
unsigned long flags;
|
||||
char rhs_val_str[VALUE_LENGTH];
|
||||
|
||||
if (suppress_report(&data->location))
|
||||
return;
|
||||
|
||||
ubsan_prologue(&data->location, &flags);
|
||||
ubsan_prologue(&data->location);
|
||||
|
||||
val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs);
|
||||
|
||||
@ -251,58 +244,52 @@ void __ubsan_handle_divrem_overflow(struct overflow_data *data,
|
||||
else
|
||||
pr_err("division by zero\n");
|
||||
|
||||
ubsan_epilogue(&flags);
|
||||
ubsan_epilogue();
|
||||
}
|
||||
EXPORT_SYMBOL(__ubsan_handle_divrem_overflow);
|
||||
|
||||
static void handle_null_ptr_deref(struct type_mismatch_data_common *data)
|
||||
{
|
||||
unsigned long flags;
|
||||
|
||||
if (suppress_report(data->location))
|
||||
return;
|
||||
|
||||
ubsan_prologue(data->location, &flags);
|
||||
ubsan_prologue(data->location);
|
||||
|
||||
pr_err("%s null pointer of type %s\n",
|
||||
type_check_kinds[data->type_check_kind],
|
||||
data->type->type_name);
|
||||
|
||||
ubsan_epilogue(&flags);
|
||||
ubsan_epilogue();
|
||||
}
|
||||
|
||||
static void handle_misaligned_access(struct type_mismatch_data_common *data,
|
||||
unsigned long ptr)
|
||||
{
|
||||
unsigned long flags;
|
||||
|
||||
if (suppress_report(data->location))
|
||||
return;
|
||||
|
||||
ubsan_prologue(data->location, &flags);
|
||||
ubsan_prologue(data->location);
|
||||
|
||||
pr_err("%s misaligned address %p for type %s\n",
|
||||
type_check_kinds[data->type_check_kind],
|
||||
(void *)ptr, data->type->type_name);
|
||||
pr_err("which requires %ld byte alignment\n", data->alignment);
|
||||
|
||||
ubsan_epilogue(&flags);
|
||||
ubsan_epilogue();
|
||||
}
|
||||
|
||||
static void handle_object_size_mismatch(struct type_mismatch_data_common *data,
|
||||
unsigned long ptr)
|
||||
{
|
||||
unsigned long flags;
|
||||
|
||||
if (suppress_report(data->location))
|
||||
return;
|
||||
|
||||
ubsan_prologue(data->location, &flags);
|
||||
ubsan_prologue(data->location);
|
||||
pr_err("%s address %p with insufficient space\n",
|
||||
type_check_kinds[data->type_check_kind],
|
||||
(void *) ptr);
|
||||
pr_err("for an object of type %s\n", data->type->type_name);
|
||||
ubsan_epilogue(&flags);
|
||||
ubsan_epilogue();
|
||||
}
|
||||
|
||||
static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data,
|
||||
@ -351,25 +338,23 @@ EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1);
|
||||
|
||||
void __ubsan_handle_out_of_bounds(struct out_of_bounds_data *data, void *index)
|
||||
{
|
||||
unsigned long flags;
|
||||
char index_str[VALUE_LENGTH];
|
||||
|
||||
if (suppress_report(&data->location))
|
||||
return;
|
||||
|
||||
ubsan_prologue(&data->location, &flags);
|
||||
ubsan_prologue(&data->location);
|
||||
|
||||
val_to_string(index_str, sizeof(index_str), data->index_type, index);
|
||||
pr_err("index %s is out of range for type %s\n", index_str,
|
||||
data->array_type->type_name);
|
||||
ubsan_epilogue(&flags);
|
||||
ubsan_epilogue();
|
||||
}
|
||||
EXPORT_SYMBOL(__ubsan_handle_out_of_bounds);
|
||||
|
||||
void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data,
|
||||
void *lhs, void *rhs)
|
||||
{
|
||||
unsigned long flags;
|
||||
struct type_descriptor *rhs_type = data->rhs_type;
|
||||
struct type_descriptor *lhs_type = data->lhs_type;
|
||||
char rhs_str[VALUE_LENGTH];
|
||||
@ -379,7 +364,7 @@ void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data,
|
||||
if (suppress_report(&data->location))
|
||||
goto out;
|
||||
|
||||
ubsan_prologue(&data->location, &flags);
|
||||
ubsan_prologue(&data->location);
|
||||
|
||||
val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs);
|
||||
val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs);
|
||||
@ -402,7 +387,7 @@ void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data,
|
||||
lhs_str, rhs_str,
|
||||
lhs_type->type_name);
|
||||
|
||||
ubsan_epilogue(&flags);
|
||||
ubsan_epilogue();
|
||||
out:
|
||||
user_access_restore(ua_flags);
|
||||
}
|
||||
@ -411,11 +396,9 @@ EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds);
|
||||
|
||||
void __ubsan_handle_builtin_unreachable(struct unreachable_data *data)
|
||||
{
|
||||
unsigned long flags;
|
||||
|
||||
ubsan_prologue(&data->location, &flags);
|
||||
ubsan_prologue(&data->location);
|
||||
pr_err("calling __builtin_unreachable()\n");
|
||||
ubsan_epilogue(&flags);
|
||||
ubsan_epilogue();
|
||||
panic("can't return from __builtin_unreachable()");
|
||||
}
|
||||
EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable);
|
||||
@ -423,19 +406,18 @@ EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable);
|
||||
void __ubsan_handle_load_invalid_value(struct invalid_value_data *data,
|
||||
void *val)
|
||||
{
|
||||
unsigned long flags;
|
||||
char val_str[VALUE_LENGTH];
|
||||
|
||||
if (suppress_report(&data->location))
|
||||
return;
|
||||
|
||||
ubsan_prologue(&data->location, &flags);
|
||||
ubsan_prologue(&data->location);
|
||||
|
||||
val_to_string(val_str, sizeof(val_str), data->type, val);
|
||||
|
||||
pr_err("load of value %s is not a valid value for type %s\n",
|
||||
val_str, data->type->type_name);
|
||||
|
||||
ubsan_epilogue(&flags);
|
||||
ubsan_epilogue();
|
||||
}
|
||||
EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user