From: Daniel Vetter <daniel.vetter@xxxxxxxx> Subject: mm: don't let userspace spam allocations warnings memdump_user usually gets fed unchecked userspace input. Blasting a full backtrace into dmesg every time is a bit excessive - I'm not sure on the kernel rule in general, but at least in drm we're trying not to let unpriviledge userspace spam the logs freely. Definitely not entire warning backtraces. It also means more filtering for our CI, because our testsuite exercises these corner cases and so hits these a lot. Link: http://lkml.kernel.org/r/20190220204058.11676-1-daniel.vetter@xxxxxxxx Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Cc: Roman Gushchin <guro@xxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Jan Stancek <jstancek@xxxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx> Cc: Huang Ying <ying.huang@xxxxxxxxx> Cc: Bartosz Golaszewski <brgl@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- --- a/mm/util.c~mm-dont-let-userspace-spam-allocations-warnings +++ a/mm/util.c @@ -150,7 +150,7 @@ void *memdup_user(const void __user *src { void *p; - p = kmalloc_track_caller(len, GFP_USER); + p = kmalloc_track_caller(len, GFP_USER | __GFP_NOWARN); if (!p) return ERR_PTR(-ENOMEM); _
