On Mon, Oct 17, 2016 at 10:13 AM, Andrey Ryabinin
<aryabi...@virtuozzo.com> wrote:
>
>
> On 10/14/2016 08:10 PM, Dmitry Vyukov wrote:
>> If user sets panic_on_warn, he wants kernel to panic if there is
>> anything barely wrong with the kernel. KASAN-detected errors
>> are definitely not less benign than an arbitrary kernel WARNING.
>>
>> Panic after KASAN errors if panic_on_warn is set.
>>
>> We use this for continuous fuzzing where we want kernel to stop
>> and reboot on any error.
>>
>> Signed-off-by: Dmitry Vyukov <dvyu...@google.com>
>> Cc: kasan-...@googlegroups.com
>> Cc: Andrey Ryabinin <aryabi...@virtuozzo.com>
>> Cc: Alexander Potapenko <gli...@google.com>
>> Cc: Andrew Morton <a...@linux-foundation.org>
>> Cc: linux...@kvack.org
>> Cc: linux-kernel@vger.kernel.org
>> ---
>> mm/kasan/report.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/mm/kasan/report.c b/mm/kasan/report.c
>> index 24c1211..ca0bd48 100644
>> --- a/mm/kasan/report.c
>> +++ b/mm/kasan/report.c
>> @@ -133,6 +133,10 @@ static void kasan_end_report(unsigned long *flags)
>>
>> pr_err("==================================================================\n");
>> add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
>> spin_unlock_irqrestore(&report_lock, *flags);
>> + if (panic_on_warn) {
>> + panic_on_warn = 0;
>
> Why we need to reset panic_on_warn?
> I assume this was copied from __warn(). AFAIU in __warn() this protects from
> recursion:
> __warn() -> painc() ->__warn() -> panic() -> ...
> which is possible if WARN_ON() triggered in panic().
> But KASAN is protected from such recursion via kasan_disable_current().
But we have recursion into panic via kasan->panic->warning->panic. Am
I missing something?
>> + panic("panic_on_warn set ...\n");
>> + }
>> kasan_enable_current();
>> }
