lib/bug.c: make panic_on_warn available for all architectures

Christian Borntraeger reported that panic_on_warn doesn't have any
effect on s390.

The panic_on_warn feature was introduced with 9e3961a09798 ("kernel: add
panic_on_warn").  However it did care only for the case when
WANT_WARN_ON_SLOWPATH is defined.  This is turn is only the case for
architectures which do not have an own __WARN_TAINT defined.

Other architectures which do have __WARN_TAINT defined call report_bug()
for warnings within lib/bug.c which does not call panic() in case
panic_on_warn is set.

Let's simply enable the panic_on_warn feature by adding the same code
like it was added to warn_slowpath_common() in panic.c.

This enables panic_on_warn also for arm64, parisc, powerpc, s390 and sh.

Signed-off-by: Heiko Carstens <[email protected]>
Reported-by: Christian Borntraeger <[email protected]>
Tested-by: Christian Borntraeger <[email protected]>
Acked-by: Prarit Bhargava <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Tested-by: Michael Ellerman <[email protected]> (powerpc)
Cc: Martin Schwidefsky <[email protected]>
Cc: Heiko Carstens <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 11 insertions, 0 deletions

diff --git a/lib/bug.c b/lib/bug.c
index cff145f032a5..6cde380f09de 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -175,6 +175,17 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
 			pr_warn("WARNING: at %p [verbose debug info unavailable]\n",
 				(void *)bugaddr);
 
+		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");
+		}
+
 		print_modules();
 		show_regs(regs);
 		print_oops_end_marker();