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SubjectRe: [BUG] at include/linux/page-flags.h:415 (PageTransHuge)
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.

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:
--
1.8.4



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