2022-01-31 09:29:24

by Tiezhu Yang

[permalink] [raw]
Subject: [PATCH 5/5] kfence: unset panic_on_warn before calling panic()

As done in the full WARN() handler, panic_on_warn needs to be cleared
before calling panic() to avoid recursive panics.

Signed-off-by: Tiezhu Yang <[email protected]>
---
mm/kfence/report.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/mm/kfence/report.c b/mm/kfence/report.c
index f93a7b2..9d61a23 100644
--- a/mm/kfence/report.c
+++ b/mm/kfence/report.c
@@ -267,8 +267,16 @@ void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *r

lockdep_on();

- if (panic_on_warn)
+ if (panic_on_warn) {
+ /*
+ * This thread may hit another WARN() in the panic path.
+ * Resetting this prevents additional WARN() from panicking the
+ * system on this thread. Other threads are blocked by the
+ * panic_mutex in panic().
+ */
+ panic_on_warn = 0;
panic("panic_on_warn set ...\n");
+ }

/* We encountered a memory safety error, taint the kernel! */
add_taint(TAINT_BAD_PAGE, LOCKDEP_STILL_OK);
--
2.1.0