From 12f60018f63b899b89299da435ca2de3bd47f2f2 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Tue, 25 Oct 2016 09:51:14 -0500 Subject: mm/page_alloc: Remove kernel address exposure in free_reserved_area() commit adb1fe9ae2ee6ef6bc10f3d5a588020e7664dfa7 upstream. Linus suggested we try to remove some of the low-hanging fruit related to kernel address exposure in dmesg. The only leaks I see on my local system are: Freeing SMP alternatives memory: 32K (ffffffff9e309000 - ffffffff9e311000) Freeing initrd memory: 10588K (ffffa0b736b42000 - ffffa0b737599000) Freeing unused kernel memory: 3592K (ffffffff9df87000 - ffffffff9e309000) Freeing unused kernel memory: 1352K (ffffa0b7288ae000 - ffffa0b728a00000) Freeing unused kernel memory: 632K (ffffa0b728d62000 - ffffa0b728e00000) Linus says: "I suspect we should just remove [the addresses in the 'Freeing' messages]. I'm sure they are useful in theory, but I suspect they were more useful back when the whole "free init memory" was originally done. These days, if we have a use-after-free, I suspect the init-mem situation is the easiest situation by far. Compared to all the dynamic allocations which are much more likely to show it anyway. So having debug output for that case is likely not all that productive." With this patch the freeing messages now look like this: Freeing SMP alternatives memory: 32K Freeing initrd memory: 10588K Freeing unused kernel memory: 3592K Freeing unused kernel memory: 1352K Freeing unused kernel memory: 632K Suggested-by: Linus Torvalds Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/6836ff90c45b71d38e5d4405aec56fa9e5d1d4b2.1477405374.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar Cc: Kees Cook Signed-off-by: Greg Kroah-Hartman --- mm/page_alloc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'mm/page_alloc.c') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index bd17a6bdf131..8b80115e4e9e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5847,8 +5847,8 @@ unsigned long free_reserved_area(void *start, void *end, int poison, char *s) } if (pages && s) - pr_info("Freeing %s memory: %ldK (%p - %p)\n", - s, pages << (PAGE_SHIFT - 10), start, end); + pr_info("Freeing %s memory: %ldK\n", + s, pages << (PAGE_SHIFT - 10)); return pages; } -- cgit v1.2.3 From 78c04996b5888526c7aa3c9debe9dc56519ab81e Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Tue, 10 Jan 2017 16:58:00 -0800 Subject: mm: don't dereference struct page fields of invalid pages [ Upstream commit f073bdc51771f5a5c7a8d1191bfc3ae371d44de7 ] The VM_BUG_ON() check in move_freepages() checks whether the node id of a page matches the node id of its zone. However, it does this before having checked whether the struct page pointer refers to a valid struct page to begin with. This is guaranteed in most cases, but may not be the case if CONFIG_HOLES_IN_ZONE=y. So reorder the VM_BUG_ON() with the pfn_valid_within() check. Link: http://lkml.kernel.org/r/1481706707-6211-2-git-send-email-ard.biesheuvel@linaro.org Signed-off-by: Ard Biesheuvel Acked-by: Will Deacon Cc: Catalin Marinas Cc: Hanjun Guo Cc: Yisheng Xie Cc: Robert Richter Cc: James Morse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- mm/page_alloc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'mm/page_alloc.c') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 8b80115e4e9e..f9d648fce8cd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1527,14 +1527,14 @@ int move_freepages(struct zone *zone, #endif for (page = start_page; page <= end_page;) { - /* Make sure we are not inadvertently changing nodes */ - VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); - if (!pfn_valid_within(page_to_pfn(page))) { page++; continue; } + /* Make sure we are not inadvertently changing nodes */ + VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); + if (!PageBuddy(page)) { page++; continue; -- cgit v1.2.3 From 9ea732ebb53fdba26140989ac351dbc82056f224 Mon Sep 17 00:00:00 2001 From: Jonathan Toppins Date: Thu, 10 Aug 2017 15:23:35 -0700 Subject: mm: ratelimit PFNs busy info message commit 75dddef32514f7aa58930bde6a1263253bc3d4ba upstream. The RDMA subsystem can generate several thousand of these messages per second eventually leading to a kernel crash. Ratelimit these messages to prevent this crash. Doug said: "I've been carrying a version of this for several kernel versions. I don't remember when they started, but we have one (and only one) class of machines: Dell PE R730xd, that generate these errors. When it happens, without a rate limit, we get rcu timeouts and kernel oopses. With the rate limit, we just get a lot of annoying kernel messages but the machine continues on, recovers, and eventually the memory operations all succeed" And: "> Well... why are all these EBUSY's occurring? It sounds inefficient > (at least) but if it is expected, normal and unavoidable then > perhaps we should just remove that message altogether? I don't have an answer to that question. To be honest, I haven't looked real hard. We never had this at all, then it started out of the blue, but only on our Dell 730xd machines (and it hits all of them), but no other classes or brands of machines. And we have our 730xd machines loaded up with different brands and models of cards (for instance one dedicated to mlx4 hardware, one for qib, one for mlx5, an ocrdma/cxgb4 combo, etc), so the fact that it hit all of the machines meant it wasn't tied to any particular brand/model of RDMA hardware. To me, it always smelled of a hardware oddity specific to maybe the CPUs or mainboard chipsets in these machines, so given that I'm not an mm expert anyway, I never chased it down. A few other relevant details: it showed up somewhere around 4.8/4.9 or thereabouts. It never happened before, but the prinkt has been there since the 3.18 days, so possibly the test to trigger this message was changed, or something else in the allocator changed such that the situation started happening on these machines? And, like I said, it is specific to our 730xd machines (but they are all identical, so that could mean it's something like their specific ram configuration is causing the allocator to hit this on these machine but not on other machines in the cluster, I don't want to say it's necessarily the model of chipset or CPU, there are other bits of identicalness between these machines)" Link: http://lkml.kernel.org/r/499c0f6cc10d6eb829a67f2a4d75b4228a9b356e.1501695897.git.jtoppins@redhat.com Signed-off-by: Jonathan Toppins Reviewed-by: Doug Ledford Tested-by: Doug Ledford Cc: Michal Hocko Cc: Vlastimil Babka Cc: Mel Gorman Cc: Hillf Danton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/page_alloc.c') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f9d648fce8cd..53286b2f5b1c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6804,7 +6804,7 @@ int alloc_contig_range(unsigned long start, unsigned long end, /* Make sure the range is really isolated. */ if (test_pages_isolated(outer_start, end, false)) { - pr_info("%s: [%lx, %lx) PFNs busy\n", + pr_info_ratelimited("%s: [%lx, %lx) PFNs busy\n", __func__, outer_start, end); ret = -EBUSY; goto done; -- cgit v1.2.3