From: David Gow davidgow@google.com
commit be4f1ae978ffe98cc95ec49ceb95386fb4474974 upstream.
KASAN errors will currently trigger a panic when panic_on_warn is set. This renders kasan_multishot useless, as further KASAN errors won't be reported if the kernel has already paniced. By making kasan_multishot disable this behaviour for KASAN errors, we can still have the benefits of panic_on_warn for non-KASAN warnings, yet be able to use kasan_multishot.
This is particularly important when running KASAN tests, which need to trigger multiple KASAN errors: previously these would panic the system if panic_on_warn was set, now they can run (and will panic the system should non-KASAN warnings show up).
Signed-off-by: David Gow davidgow@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Tested-by: Andrey Konovalov andreyknvl@google.com Reviewed-by: Andrey Konovalov andreyknvl@google.com Reviewed-by: Brendan Higgins brendanhiggins@google.com Cc: Andrey Ryabinin aryabinin@virtuozzo.com Cc: Dmitry Vyukov dvyukov@google.com Cc: Ingo Molnar mingo@redhat.com Cc: Juri Lelli juri.lelli@redhat.com Cc: Patricia Alfonso trishalfonso@google.com Cc: Peter Zijlstra a.p.zijlstra@chello.nl Cc: Shuah Khan shuah@kernel.org Cc: Vincent Guittot vincent.guittot@linaro.org Link: https://lkml.kernel.org/r/20200915035828.570483-6-davidgow@google.com Link: https://lkml.kernel.org/r/20200910070331.3358048-6-davidgow@google.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Eric Biggers ebiggers@google.com --- mm/kasan/report.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 6bcfb01ba0386..5b421f8433488 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -172,7 +172,7 @@ 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) + if (panic_on_warn && !test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags)) panic("panic_on_warn set ...\n"); kasan_enable_current(); }