On 2022/11/19 05:42, Andrew Morton wrote:
On Fri, 18 Nov 2022 18:00:11 +0800 Qi Zheng zhengqi.arch@bytedance.com wrote:
When we specify __GFP_NOWARN, we only expect that no warnings will be issued for current caller. But in the __should_failslab() and __should_fail_alloc_page(), the local GFP flags alter the global {failslab|fail_page_alloc}.attr, which is persistent and shared by all tasks. This is not what we expected, let's fix it.
Cc: stable@vger.kernel.org Fixes: 3f913fc5f974 ("mm: fix missing handler for __GFP_NOWARN") Reported-by: Dmitry Vyukov dvyukov@google.com Signed-off-by: Qi Zheng zhengqi.arch@bytedance.com Reviewed-by: Akinobu Mita akinobu.mita@gmail.com
...
-bool should_fail(struct fault_attr *attr, ssize_t size) +bool should_fail_ex(struct fault_attr *attr, ssize_t size, int flags) { bool stack_checked = false; @@ -152,13 +149,20 @@ bool should_fail(struct fault_attr *attr, ssize_t size) return false; fail:
- fail_dump(attr);
- if (!(flags & FAULT_NOWARN))
fail_dump(attr);if (atomic_read(&attr->times) != -1) atomic_dec_not_zero(&attr->times); return true; } +EXPORT_SYMBOL_GPL(should_fail_ex);
I don't see a need to export this?
Yes, my initial thought was that there might be a driver using this function, but there really isn't one yet.
And I see you've helped remove this, thanks a lot. :)