| Message ID | 20230330162625.13604-1-laoar.shao@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] mm: vmalloc: Avoid warn_alloc noise caused by fatal signal | expand |
On Thu, 30 Mar 2023 16:26:25 +0000 Yafang Shao <laoar.shao@gmail.com> wrote: > There're some suspicious warn_alloc on my test serer, for example, > > [13366.518837] warn_alloc: 81 callbacks suppressed > [13366.518841] test_verifier: vmalloc error: size 4096, page order 0, failed to allocate pages, mode:0x500dc2(GFP_HIGHUSER|__GFP_ZERO|__GFP_ACCOUNT), nodemask=(null),cpuset=/,mems_allowed=0-1 > [13366.522240] CPU: 30 PID: 722463 Comm: test_verifier Kdump: loaded Tainted: G W O 6.2.0+ #638 > [13366.524216] Call Trace: > > ... > > This failure really confuse me as there're still lots of available > pages. Finally I figured out it was caused by a fatal signal. When a > process is allocating memory via vm_area_alloc_pages(), it will break > directly even if it hasn't allocated the requested pages when it > receives a fatal signal. In that case, we shouldn't show this warn_alloc, > as it is useless. We only need to show this warning when there're really > no enough pages. > > ... > > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3024,9 +3024,11 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, > * allocation request, free them via vfree() if any. > */ > if (area->nr_pages != nr_small_pages) { > - warn_alloc(gfp_mask, NULL, > - "vmalloc error: size %lu, page order %u, failed to allocate pages", > - area->nr_pages * PAGE_SIZE, page_order); > + /* vm_area_alloc_pages() can also fail due to a fatal signal */ > + if (!fatal_signal_pending(current)) > + warn_alloc(gfp_mask, NULL, > + "vmalloc error: size %lu, page order %u, failed to allocate pages", > + area->nr_pages * PAGE_SIZE, page_order); > goto fail; > } Emitting erroneous splats into dmesg is pretty unpleasant, so I'll put a cc:stable on this one. I can't identify a suitable Fixes: target - the code around there has changed several times in fairly cosmetic ways so each of the various -stable kernels will probably need different versions of the patch.
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index ef910bf..a1ffdb0 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3024,9 +3024,11 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, * allocation request, free them via vfree() if any. */ if (area->nr_pages != nr_small_pages) { - warn_alloc(gfp_mask, NULL, - "vmalloc error: size %lu, page order %u, failed to allocate pages", - area->nr_pages * PAGE_SIZE, page_order); + /* vm_area_alloc_pages() can also fail due to a fatal signal */ + if (!fatal_signal_pending(current)) + warn_alloc(gfp_mask, NULL, + "vmalloc error: size %lu, page order %u, failed to allocate pages", + area->nr_pages * PAGE_SIZE, page_order); goto fail; }