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authorKees Cook <keescook@chromium.org>2022-12-16 12:26:57 -0800
committerKees Cook <keescook@chromium.org>2022-12-16 12:26:57 -0800
commit7535b832c6399b5ebfc5b53af5c51dd915ee2538 (patch)
treeeb9699155cf89e65084179522b93106ad2f33faf /kernel/panic.c
parentd6a9fb87e9d18f3394a9845546bbe868efdccfd2 (diff)
exit: Use READ_ONCE() for all oops/warn limit reads
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>
Diffstat (limited to 'kernel/panic.c')
-rw-r--r--kernel/panic.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/panic.c b/kernel/panic.c
index 54deb743b2d5..7834c9854e02 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -231,12 +231,15 @@ static void panic_print_sys_info(bool console_flush)
void check_panic_on_warn(const char *origin)
{
+ unsigned int limit;
+
if (panic_on_warn)
panic("%s: panic_on_warn set ...\n", origin);
- if (atomic_inc_return(&warn_count) >= READ_ONCE(warn_limit) && warn_limit)
+ limit = READ_ONCE(warn_limit);
+ if (atomic_inc_return(&warn_count) >= limit && limit)
panic("%s: system warned too often (kernel.warn_limit is %d)",
- origin, warn_limit);
+ origin, limit);
}
/**