From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f181.google.com (mail-wi0-f181.google.com [209.85.212.181]) by kanga.kvack.org (Postfix) with ESMTP id D86916B025B for ; Fri, 25 Sep 2015 15:13:10 -0400 (EDT) Received: by wicgb1 with SMTP id gb1so33146377wic.1 for ; Fri, 25 Sep 2015 12:13:10 -0700 (PDT) Received: from mail-wi0-f170.google.com (mail-wi0-f170.google.com. [209.85.212.170]) by mx.google.com with ESMTPS id t9si6277690wiz.2.2015.09.25.12.13.09 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 25 Sep 2015 12:13:09 -0700 (PDT) Received: by wiclk2 with SMTP id lk2so31815967wic.1 for ; Fri, 25 Sep 2015 12:13:09 -0700 (PDT) Date: Fri, 25 Sep 2015 22:13:07 +0300 From: "Kirill A. Shutemov" Subject: Re: [PATCH 03/16] page-flags: introduce page flags policies wrt compound pages Message-ID: <20150925191307.GA25711@node.dhcp.inet.fi> References: <20150921153509.fef7ecdf313ef74307c43b65@linux-foundation.org> <1443106264-78075-1-git-send-email-kirill.shutemov@linux.intel.com> <1443106264-78075-4-git-send-email-kirill.shutemov@linux.intel.com> <56053E1D.7050001@yandex-team.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56053E1D.7050001@yandex-team.ru> Sender: owner-linux-mm@kvack.org List-ID: To: Konstantin Khlebnikov Cc: "Kirill A. Shutemov" , Andrew Morton , Andrea Arcangeli , Hugh Dickins , Dave Hansen , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , "Aneesh Kumar K.V" , Johannes Weiner , Michal Hocko , Jerome Marchand , Sasha Levin , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Fri, Sep 25, 2015 at 03:29:17PM +0300, Konstantin Khlebnikov wrote: > On 24.09.2015 17:50, Kirill A. Shutemov wrote: > >This patch adds a third argument to macros which create function > >definitions for page flags. This argument defines how page-flags helpers > >behave on compound functions. > > > >For now we define four policies: > > > >- PF_ANY: the helper function operates on the page it gets, regardless > > if it's non-compound, head or tail. > > > >- PF_HEAD: the helper function operates on the head page of the compound > > page if it gets tail page. > > > >- PF_NO_TAIL: only head and non-compond pages are acceptable for this > > helper function. > > > >- PF_NO_COMPOUND: only non-compound pages are acceptable for this helper > > function. > > > >For now we use policy PF_ANY for all helpers, which matches current > >behaviour. > > > >We do not enforce the policy for TESTPAGEFLAG, because we have flags > >checked for random pages all over the kernel. Noticeable exception to > >this is PageTransHuge() which triggers VM_BUG_ON() for tail page. > > > >Signed-off-by: Kirill A. Shutemov > >--- > > include/linux/page-flags.h | 154 ++++++++++++++++++++++++++------------------- > > 1 file changed, 90 insertions(+), 64 deletions(-) > > > >diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > >index 713d3f2c2468..1b3babe5ff69 100644 > >--- a/include/linux/page-flags.h > >+++ b/include/linux/page-flags.h > >@@ -154,49 +154,68 @@ static inline int PageCompound(struct page *page) > > return test_bit(PG_head, &page->flags) || PageTail(page); > > } > > > >+/* Page flags policies wrt compound pages */ > >+#define PF_ANY(page, enforce) page > >+#define PF_HEAD(page, enforce) compound_head(page) > >+#define PF_NO_TAIL(page, enforce) ({ \ > >+ if (enforce) \ > >+ VM_BUG_ON_PAGE(PageTail(page), page); \ > >+ else \ > >+ page = compound_head(page); \ > >+ page;}) > >+#define PF_NO_COMPOUND(page, enforce) ({ \ > >+ if (enforce) \ > >+ VM_BUG_ON_PAGE(PageCompound(page), page); \ > > Linux next-20150925 crashes here (at least in lkvm) > if CONFIG_DEFERRED_STRUCT_PAGE_INIT=y Hm. I don't see the crash in qemu. Could you share your config? > [ 0.000000] Kernel command line: noapic noacpi pci=conf1 reboot=k panic=1 > i8042.direct=1 i8042.dumbkbd=1 i8042.nopnp=1 console=ttyS0 > earlyprintk=serial i8042.noaux=1 root=/dev/root rw > rootflags=rw,trans=virtio,version=9p2000.L rootfstype=9p init=/virt/init > ip=dhcp > [ 0.000000] PID hash table entries: 2048 (order: 2, 16384 bytes) > [ 0.000000] BUG: unable to handle kernel NULL pointer dereference at > 000000000000000c > [ 0.000000] IP: [] dump_page_badflags+0x2b/0xe0 > [ 0.000000] PGD 0 > [ 0.000000] Oops: 0000 [#1] SMP > [ 0.000000] Modules linked in: > [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted > 4.3.0-rc2-next-20150925+ #2 > [ 0.000000] task: ffffffff81c12580 ti: ffffffff81c00000 task.ti: > ffffffff81c00000 > [ 0.000000] RIP: 0010:[] [] > dump_page_badflags+0x2b/0xe0 > [ 0.000000] RSP: 0000:ffffffff81c03ea8 EFLAGS: 00010002 > [ 0.000000] RAX: 000000000000000c RBX: ffffea00006dfd40 RCX: > 0000000000000100 > [ 0.000000] RDX: 0000000000000001 RSI: ffffffff81a4aeb8 RDI: > ffffea00006dfd40 > [ 0.000000] RBP: ffffffff81c03ec0 R08: 0000000000000000 R09: > 0000000000000000 > [ 0.000000] R10: 0000000000000001 R11: 0000000000000000 R12: > 0000000000000000 > [ 0.000000] R13: 000000000001b7f7 R14: ffffffff81fe50c0 R15: > ffffffff81c03fb0 > [ 0.000000] FS: 0000000000000000(0000) GS:ffff88001a400000(0000) > knlGS:0000000000000000 > [ 0.000000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 0.000000] CR2: 000000000000000c CR3: 0000000001c0b000 CR4: > 00000000000406b0 > [ 0.000000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: > 0000000000000000 > [ 0.000000] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: > 0000000000000400 > [ 0.000000] Stack: > [ 0.000000] 000000000001b7f5 ffffea00006dfd40 000000000001b7f7 > ffffffff81c03ed0 > [ 0.000000] ffffffff811aabc0 ffffffff81c03ef8 ffffffff81785eda > ffffffff81c03f10 > [ 0.000000] 0000000000000040 ffffffff81fd99c0 ffffffff81c03f30 > ffffffff81f66600 > [ 0.000000] Call Trace: > [ 0.000000] [] dump_page+0x10/0x20 > [ 0.000000] [] reserve_bootmem_region+0xd9/0xe2 > [ 0.000000] [] free_all_bootmem+0x4b/0x11a > [ 0.000000] [] mem_init+0x6a/0x9d > [ 0.000000] [] start_kernel+0x214/0x46a > [ 0.000000] [] ? early_idt_handler_array+0x120/0x120 > [ 0.000000] [] x86_64_start_reservations+0x2a/0x2c > [ 0.000000] [] x86_64_start_kernel+0x136/0x145 > [ 0.000000] Code: e8 3b 7b 5e 00 55 48 89 e5 41 55 41 54 49 89 d4 53 48 > 8b 57 20 48 89 fb 4c 8b 4f 10 4c 8b 47 08 48 8d 42 ff 83 e2 01 48 0f 44 c7 > <48> 8b 00 a8 80 75 4b 8b 4f 18 8b 57 1c 49 89 f5 31 c0 48 89 fe > [ 0.000000] RIP [] dump_page_badflags+0x2b/0xe0 > [ 0.000000] RSP > [ 0.000000] CR2: 000000000000000c > [ 0.000000] ---[ end trace cb88537fdc8fa200 ]--- Could you try this: diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 9bcfd70b1eb8..eff685f83879 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -929,8 +929,6 @@ static void init_reserved_page(unsigned long pfn) #else static inline void init_reserved_page(unsigned long pfn) { - /* Avoid false-positive PageTail() */ - INIT_LIST_HEAD(&pfn_to_page(pfn)->lru); } #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */ @@ -950,6 +948,10 @@ void __meminit reserve_bootmem_region(unsigned long start, unsigned long end) struct page *page = pfn_to_page(start_pfn); init_reserved_page(start_pfn); + + /* Avoid false-positive PageTail() */ + INIT_LIST_HEAD(&pfn_to_page(pfn)->lru); + SetPageReserved(page); } } -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org