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SubjectRe: [BUG] at include/linux/page-flags.h:415 (PageTransHuge)
On 01/13/2014 11:16 AM, Vlastimil Babka wrote:
> On 01/11/2014 02:32 PM, Daniel Borkmann wrote:
>> On 01/11/2014 07:22 AM, Andrew Morton wrote:
>>> On Fri, 10 Jan 2014 19:23:26 +0100 Daniel Borkmann <borkmann@iogearbox.net> wrote:
>>>
>>>> This is being reliably triggered for each mmaped() packet(7)
>>>> socket from user space, basically during unmapping resp.
>>>> closing the TX socket.
>>>>
>>>> I believe due to some change in transparent hugepages code ?
>>>>
>>>> When I disable transparent hugepages, everything works fine,
>>>> no BUG triggered.
>>>>
>>>> I'd be happy to test patches.
>>>
>>> Did the inclusion of c424be1cbbf852e46acc8 ("mm: munlock: fix a bug
>>> where THP tail page is encountered") in current mainline fix this?
>>
>> Thanks for your answer Andrew!
>>
>> Hm, I just cherry-picked that onto current net-next as I have some work
>> there, and this time I got ...
>>
>> (User space uses packet mmap() and mlockall(MCL_CURRENT | MCL_FUTURE)
>> and on shutdown munlockall() ...)
>>
>> [ 63.863672] ------------[ cut here ]------------
>> [ 63.863702] kernel BUG at mm/mlock.c:507!
>> [ 63.863721] invalid opcode: 0000 [#1] SMP
>> [ 63.863743] Modules linked in: fuse ebtable_nat xt_CHECKSUM nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6table_nat nf_nat_ipv6 ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 iptable_nat nf_nat_ipv4 nf_nat iptable_mangle nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack bridge ebtable_filter ebtables stp llc ip6table_filter ip6_tables rfcomm bnep snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_intel snd_hda_codec iwlwifi cfg80211 snd_hwdep btusb snd_seq bluetooth sdhci_pci snd_seq_device e1000e tpm_tis snd_pcm thinkpad_acpi sdhci ptp tpm uvcvideo pps_core snd_page_alloc snd_timer snd rfkill mmc_core iTCO_wdt iTCO_vendor_support lpc_ich mfd_core soundcore joydev wmi videobuf2_vmalloc videobuf2_memops videobuf2_core i2c_i801 pcspkr videodev media uinput i915
>> [ 63.864152] i2c_algo_bit drm_kms_helper drm i2c_core video
>> [ 63.864181] CPU: 1 PID: 1617 Comm: trafgen Not tainted 3.13.0-rc6+ #15
>> [ 63.864209] Hardware name: LENOVO 2429BP3/2429BP3, BIOS G4ET37WW (1.12 ) 05/29/2012
>> [ 63.864242] task: ffff8801ee060000 ti: ffff8800b5954000 task.ti: ffff8800b5954000
>> [ 63.864274] RIP: 0010:[<ffffffff8116fa9a>] [<ffffffff8116fa9a>] munlock_vma_pages_range+0x2ea/0x2f0
>> [ 63.864318] RSP: 0018:ffff8800b5955e08 EFLAGS: 00010202
>> [ 63.864341] RAX: 00000000000001ff RBX: ffff8800b58f7508 RCX: 0000000000000034
>> [ 63.864372] RDX: 00000007f0708992 RSI: ffffea0002c3e700 RDI: ffffea0002c3e700
>> [ 63.864402] RBP: ffff8800b5955ee0 R08: 3800000000000000 R09: a8000b0f9c000000
>> [ 63.864432] R10: 57ffdef066c3e700 R11: ffffff5cfb00c14a R12: ffffea0002c3e700
>> [ 63.864462] R13: ffff8800b5955f48 R14: 00007f0708992000 R15: 00007f0708992000
>> [ 63.864492] FS: 00007f0708b92740(0000) GS:ffff88021e240000(0000) knlGS:0000000000000000
>> [ 63.864526] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [ 63.864551] CR2: 00007f33bb373000 CR3: 00000000b2a2c000 CR4: 00000000001407e0
>> [ 63.864581] Stack:
>> [ 63.864593] ffff8800b5955ed0 00007f0708b91fff 00007f0708b92000 ffff8800b5955e48
>> [ 63.864632] 000001ff810c864b ffff8801ee060000 0000000000000000 0000000000000000
>> [ 63.864669] ffff8800b5955e58 ffff8801ee060000 0000000700000086 ffff8801ee060000
>> [ 63.864708] Call Trace:
>> [ 63.864724] [<ffffffff816956bc>] ? _raw_spin_unlock_irq+0x2c/0x30
>> [ 63.864754] [<ffffffff81171b52>] ? vma_merge+0xc2/0x330
>> [ 63.864786] [<ffffffff8116fb9c>] mlock_fixup+0xfc/0x190
>> [ 63.864812] [<ffffffff8116fde7>] do_mlockall+0x87/0xc0
>> [ 63.864836] [<ffffffff811702df>] sys_munlockall+0x2f/0x50
>> [ 63.864873] [<ffffffff8169e192>] system_call_fastpath+0x16/0x1b
>> [ 63.864898] Code: d7 48 89 95 28 ff ff ff e8 a4 04 fe ff 84 c0 48 8b 95 28 ff ff ff 0f 85 5a ff ff ff e9 46 ff ff ff e8 3f ac 51 00 e8 34 ac 51 00 <0f> 0b 0f 1f 40 00 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55
>> [ 63.865114] RIP [<ffffffff8116fa9a>] munlock_vma_pages_range+0x2ea/0x2f0
>> [ 63.865148] RSP <ffff8800b5955e08>
>> [ 63.874968] ------------[ cut here ]------------
>>
>> ... when I find some time, I'll try with normal torvalds' tree, maybe some
>> other patches are missing as well, not sure right now.
>
> Uh so the triggered assertion is the one added by this very patch, and there are no more changes wrt this in mainline.
>
> If you can still try debug patches, please try this. Thanks.

Yes, thanks, I'll come back to you some time by today.

> From: Vlastimil Babka <vbabka@suse.cz>
> Date: Mon, 13 Jan 2014 11:13:53 +0100
> Subject: [PATCH] debug munlock_vma_pages_range
>
> ---
> mm/mlock.c | 22 ++++++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/mm/mlock.c b/mm/mlock.c
> index c59c420..7d0e29a 100644
> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -448,12 +448,14 @@ static unsigned long __munlock_pagevec_fill(struct pagevec *pvec,
> void munlock_vma_pages_range(struct vm_area_struct *vma,
> unsigned long start, unsigned long end)
> {
> + unsigned long orig_start = start;
> + unsigned long page_increm = 0;
> +
> vma->vm_flags &= ~VM_LOCKED;
>
> while (start < end) {
> struct page *page = NULL;
> unsigned int page_mask;
> - unsigned long page_increm;
> struct pagevec pvec;
> struct zone *zone;
> int zoneid;
> @@ -504,7 +506,23 @@ void munlock_vma_pages_range(struct vm_area_struct *vma,
> }
> }
> /* It's a bug to munlock in the middle of a THP page */
> - VM_BUG_ON((start >> PAGE_SHIFT) & page_mask);
> + if ((start >> PAGE_SHIFT) & page_mask) {
> + dump_page(page);
> + printk("start=%lu pfn=%lu orig_start=%lu "
> + "prev_page_increm=%lu page_mask=%u "
> + "vm_start=%lu vm_end=%lu vm_flags=%lu\n",
> + start, page_to_pfn(page), orig_start,
> + page_increm, page_mask,
> + vma->vm_start, vma->vm_end,
> + vma->vm_flags);
> + if (PageTail(page)) {
> + struct page *first_page = page->first_page;
> + printk("first_page pfn=%lu\n",
> + page_to_pfn(first_page));
> + dump_page(first_page);
> + }
> + VM_BUG_ON(true);
> + }
> page_increm = 1 + page_mask;
> start += page_increm * PAGE_SIZE;
> next:
>



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