exit: Use READ_ONCE() for all oops/warn limit reads
authorKees Cook <keescook@chromium.org>
Fri, 16 Dec 2022 20:26:57 +0000 (12:26 -0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 24 Jan 2023 06:24:41 +0000 (07:24 +0100)
commita18417e27ed8dde4e774fb0611a10479d0c8eed1
tree3c99de61f7bf1dad9566ba6ce6e9f4065cfdc8e6
parent3f38c21707143ca9e728696503d8be3feb1e5486
exit: Use READ_ONCE() for all oops/warn limit reads

commit 7535b832c6399b5ebfc5b53af5c51dd915ee2538 upstream.

Use a temporary variable to take full advantage of READ_ONCE() behavior.
Without this, the report (and even the test) might be out of sync with
the initial test.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/lkml/Y5x7GXeluFmZ8E0E@hirez.programming.kicks-ass.net
Fixes: 9fc9e278a5c0 ("panic: Introduce warn_limit")
Fixes: d4ccd54d28d3 ("exit: Put an upper limit on how often we can oops")
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Jann Horn <jannh@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: tangmeng <tangmeng@uniontech.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kernel/exit.c
kernel/panic.c