The new IRQ state tracking code does not honor lockdep_off(), and as
such we should again permit tracing by using non-raw functions in
core.c. Update the lockdep_off() comment in report.c, to reflect the
fact there is still a potential risk of deadlock due to using printk()
from scheduler code.
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200624113246.GA170324@elver.google.com
}
if (!kcsan_interrupt_watcher)
- /* Use raw to avoid lockdep recursion via IRQ flags tracing. */
- raw_local_irq_save(irq_flags);
+ local_irq_save(irq_flags);
watchpoint = insert_watchpoint((unsigned long)ptr, size, is_write);
if (watchpoint == NULL) {
kcsan_counter_dec(KCSAN_COUNTER_USED_WATCHPOINTS);
out_unlock:
if (!kcsan_interrupt_watcher)
- raw_local_irq_restore(irq_flags);
+ local_irq_restore(irq_flags);
out:
user_access_restore(ua_flags);
}
goto out;
/*
- * With TRACE_IRQFLAGS, lockdep's IRQ trace state becomes corrupted if
- * we do not turn off lockdep here; this could happen due to recursion
- * into lockdep via KCSAN if we detect a race in utilities used by
- * lockdep.
+ * Because we may generate reports when we're in scheduler code, the use
+ * of printk() could deadlock. Until such time that all printing code
+ * called in print_report() is scheduler-safe, accept the risk, and just
+ * get our message out. As such, also disable lockdep to hide the
+ * warning, and avoid disabling lockdep for the rest of the kernel.
*/
lockdep_off();