From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> If LOCKDEP detects a bug while KASAN is printing a report and if panic_on_warn is set, KASAN will not be able to finish. Disable LOCKDEP while KASAN is printing a report. See https://bugzilla.kernel.org/show_bug.cgi?id=202115 for an example of the issue. Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> --- mm/kasan/report.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/kasan/report.c b/mm/kasan/report.c index c9bfffe931b4..199d77cce21a 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -13,6 +13,7 @@ #include <linux/ftrace.h> #include <linux/init.h> #include <linux/kernel.h> +#include <linux/lockdep.h> #include <linux/mm.h> #include <linux/printk.h> #include <linux/sched.h> @@ -148,6 +149,8 @@ static void start_report(unsigned long *flags, bool sync) disable_trace_on_warning(); /* Update status of the currently running KASAN test. */ update_kunit_status(sync); + /* Do not allow LOCKDEP mangling KASAN reports. */ + lockdep_off(); /* Make sure we don't end up in loop. */ kasan_disable_current(); spin_lock_irqsave(&report_lock, *flags); @@ -160,12 +163,13 @@ static void end_report(unsigned long *flags, void *addr) trace_error_report_end(ERROR_DETECTOR_KASAN, (unsigned long)addr); pr_err("==================================================================\n"); - add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); spin_unlock_irqrestore(&report_lock, *flags); if (panic_on_warn && !test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags)) panic("panic_on_warn set ...\n"); if (kasan_arg_fault == KASAN_ARG_FAULT_PANIC) panic("kasan.fault=panic set ...\n"); + add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); + lockdep_on(); kasan_enable_current(); } -- 2.25.1
