Re: [net] 03d56978dd: BUG:Bad_page_map_in_process

From: Joanne Koong
Date: Fri Aug 12 2022 - 15:02:14 EST

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In reply to: Joanne Koong: "Re: [net] 03d56978dd: BUG:Bad_page_map_in_process"
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On Tue, Aug 9, 2022 at 9:52 AM Joanne Koong <joannelkoong@xxxxxxxxx> wrote:
>
> On Fri, Aug 5, 2022 at 12:30 AM Yujie Liu <yujie.liu@xxxxxxxxx> wrote:
> >
> > Hi Joanne,
> >
> > On 7/28/2022 07:41, Joanne Koong wrote:
> > > On Sun, Jul 24, 2022 at 7:05 AM kernel test robot <oliver.sang@xxxxxxxxx> wrote:
> > >>
> > >>
> > >>
> > >> Greeting,
> > >>
> > >> FYI, we noticed the following commit (built with gcc-11):
> > >>
> > >> commit: 03d56978dd246147e151916e4dc72af7bc24d5c9 ("[PATCH net-next v3 1/3] net: Add a bhash2 table hashed by port + address")
> > >> url: https://github.com/intel-lab-lkp/linux/commits/Joanne-Koong/Add-a-second-bind-table-hashed-by-port-address/20220723-035903
> > >> base: https://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git 949d6b405e6160ae44baea39192d67b39cb7eeac
> > >> patch link: https://lore.kernel.org/netdev/20220722195406.1304948-2-joannelkoong@xxxxxxxxx
> > >>
> > >> in testcase: boot
> > >>
> > >> on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
> > >>
> > >> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
> > >>
> > >>
> > >>
> > >> If you fix the issue, kindly add following tag
> > >> Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
> > >>
> > >>
> > >> [ 103.871133][ T486] BUG: Bad page map in process rsync pte:ffff92f93b759508 pmd:13fc1e067
> > >> [ 103.873143][ T486] addr:00007f9fe52a2000 vm_flags:00000075 anon_vma:0000000000000000 mapping:ffff92f928adcb58 index:1a1
> > >> [ 103.875128][ T486] file:libcrypto.so.1.1 fault:filemap_fault mmap:generic_file_mmap read_folio:simple_read_folio
> > >> [ 103.877339][ T486] CPU: 0 PID: 486 Comm: rsync Not tainted 5.19.0-rc7-01443-g03d56978dd24 #1
> > >> [ 103.879032][ T486] Call Trace:
> > >> [ 103.879742][ T486] <TASK>
> > >> [ 103.880329][ T486] ? simple_write_end+0x140/0x140
> > >> [ 103.881338][ T486] dump_stack_lvl+0x3b/0x53
> > >> [ 103.882274][ T486] ? __filemap_get_folio+0x780/0x780
> > >> [ 103.883270][ T486] print_bad_pte.cold+0x15b/0x1c5
> > >> [ 103.884202][ T486] vm_normal_page+0x65/0x140
> > >> [ 103.885062][ T486] zap_pte_range+0x23b/0x9c0
> > >> [ 103.885897][ T486] unmap_page_range+0x263/0x5c0
> > >> [ 103.886846][ T486] unmap_vmas+0x121/0x200
> > >> [ 103.887628][ T486] exit_mmap+0xb5/0x240
> > >> [ 103.888401][ T486] mmput+0x3b/0x140
> > >> [ 103.889134][ T486] exit_mm+0xff/0x180
> > >> [ 103.889877][ T486] do_exit+0x100/0x400
> > >> [ 103.890661][ T486] do_group_exit+0x3e/0x100
> > >> [ 103.891514][ T486] __x64_sys_exit_group+0x18/0x40
> > >> [ 103.892494][ T486] do_syscall_64+0x5d/0x80
> > >> [ 103.893294][ T486] ? do_user_addr_fault+0x257/0x6c0
> > >> [ 103.894238][ T486] ? lock_release+0x6e/0x100
> > >> [ 103.895171][ T486] ? up_read+0x12/0x40
> > >> [ 103.896036][ T486] ? exc_page_fault+0xb2/0x2c0
> > >> [ 103.897021][ T486] entry_SYSCALL_64_after_hwframe+0x5d/0xc7
> > >> [ 103.898243][ T486] RIP: 0033:0x7f9fe5007699
> > >> [ 103.899149][ T486] Code: Unable to access opcode bytes at RIP 0x7f9fe500766f.
> > >> [ 103.900511][ T486] RSP: 002b:00007fff7e32c3a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
> > >> [ 103.902027][ T486] RAX: ffffffffffffffda RBX: 00007f9fe50fc610 RCX: 00007f9fe5007699
> > >> [ 103.903477][ T486] RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
> > >> [ 103.904943][ T486] RBP: 0000000000000000 R08: ffffffffffffff80 R09: 0000000000000001
> > >> [ 103.906384][ T486] R10: 000000000000000b R11: 0000000000000246 R12: 00007f9fe50fc610
> > >> [ 103.907823][ T486] R13: 0000000000000001 R14: 00007f9fe50fcae8 R15: 0000000000000000
> > >> [ 103.909290][ T486] </TASK>
> > >> [ 103.910423][ T486] Disabling lock debugging due to kernel taint
> > >> [ 107.503093][ T508] BUG: Bad page map in process rsync pte:ffff92f93b7fe508 pmd:13aa1c067
> > >> [ 107.504948][ T508] addr:00007fced9aa2000 vm_flags:00000075 anon_vma:0000000000000000 mapping:ffff92f92891ab58 index:9a
> > >> [ 107.507070][ T508] file:libzstd.so.1.4.8 fault:filemap_fault mmap:generic_file_mmap read_folio:simple_read_folio
> > >> [ 107.508825][ T508] CPU: 0 PID: 508 Comm: rsync Tainted: G B 5.19.0-rc7-01443-g03d56978dd24 #1
> > >> [ 107.510762][ T508] Call Trace:
> > >> [ 107.511458][ T508] <TASK>
> > >> [ 107.512058][ T508] ? simple_write_end+0x140/0x140
> > >> [ 107.513072][ T508] dump_stack_lvl+0x3b/0x53
> > >> [ 107.513990][ T508] ? __filemap_get_folio+0x780/0x780
> > >> [ 107.519166][ T508] print_bad_pte.cold+0x15b/0x1c5
> > >> [ 107.520032][ T508] vm_normal_page+0x65/0x140
> > >> [ 107.520802][ T508] zap_pte_range+0x23b/0x9c0
> > >> [ 107.521548][ T508] unmap_page_range+0x263/0x5c0
> > >> [ 107.522355][ T508] unmap_vmas+0x121/0x200
> > >> [ 107.523247][ T508] exit_mmap+0xb5/0x240
> > >> [ 107.524107][ T508] mmput+0x3b/0x140
> > >> [ 107.524908][ T508] exit_mm+0xff/0x180
> > >> [ 107.525716][ T508] do_exit+0x100/0x400
> > >> [ 107.526613][ T508] do_group_exit+0x3e/0x100
> > >> [ 107.527541][ T508] __x64_sys_exit_group+0x18/0x40
> > >> [ 107.528450][ T508] do_syscall_64+0x5d/0x80
> > >> [ 107.529368][ T508] ? up_read+0x12/0x40
> > >> [ 107.530228][ T508] ? do_user_addr_fault+0x257/0x6c0
> > >> [ 107.531121][ T508] ? rcu_read_lock_sched_held+0x5/0x40
> > >> [ 107.532046][ T508] ? exc_page_fault+0xb2/0x2c0
> > >> [ 107.532843][ T508] entry_SYSCALL_64_after_hwframe+0x5d/0xc7
> > >> [ 107.533866][ T508] RIP: 0033:0x7fced95ff699
> > >> [ 107.534781][ T508] Code: Unable to access opcode bytes at RIP 0x7fced95ff66f.
> > >> [ 107.536225][ T508] RSP: 002b:00007fff162474c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
> > >> [ 107.537871][ T508] RAX: ffffffffffffffda RBX: 00007fced96f4610 RCX: 00007fced95ff699
> > >> [ 107.539506][ T508] RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
> > >> [ 107.541126][ T508] RBP: 0000000000000000 R08: ffffffffffffff80 R09: 0000000000000001
> > >> [ 107.542743][ T508] R10: 000000000000000b R11: 0000000000000246 R12: 00007fced96f4610
> > >> [ 107.544310][ T508] R13: 0000000000000001 R14: 00007fced96f4ae8 R15: 0000000000000000
> > >> [ 107.545881][ T508] </TASK>
> > >>
> > >>
> > >>
> > >> To reproduce:
> > >>
> > >> # build kernel
> > >> cd linux
> > >> cp config-5.19.0-rc7-01443-g03d56978dd24 .config
> > >> make HOSTCC=gcc-11 CC=gcc-11 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage modules
> > >> make HOSTCC=gcc-11 CC=gcc-11 ARCH=x86_64 INSTALL_MOD_PATH=<mod-install-dir> modules_install
> > >> cd <mod-install-dir>
> > >> find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz
> > >>
> > >>
> > >> git clone https://github.com/intel/lkp-tests.git
> > >> cd lkp-tests
> > >> bin/lkp qemu -k <bzImage> -m modules.cgz job-script # job-script is attached in this email
> > >>
> > >> # if come across any failure that blocks the test,
> > >> # please remove ~/.lkp and /lkp dir to run from a clean state.
> > >>
> > > I ran this in a loop ~20 times but I'm not able to repro the crash.
> > > This is a snippet of what I see (and I can also attach or paste the
> > > entire log if that would be helpful):
> > >
> > > I examined more closely the changes between v2 and v3 and I don't see
> > > anything that would lead to this error either (I'm assuming v2 is
> > > okay because this report wasn't generated for it). Looking at the
> > > stack trace too, I'm not seeing anything that sticks out (eg this
> > > looks like a memory mapping failure and bhash2 didn't modify mapping
> > > or paging code).
> >
> > We chose commit 949d6b405e61 (net: add missing includes and forward
> > declarations under net/) as base, which used to be the head of
> > net-next/master branch then, and apply your v3 patches on top of it.
> > So the test result is a comparison between 949d6b405e61 and v3.
> >
> > Refer to the bug info:
> >
> > [ 103.871133][ T486] BUG: Bad page map in process rsync pte:ffff92f93b759508 pmd:13fc1e067
> >
> > The BUG happens in rsync, and it reminds me that we have some extra
> > steps when running the test in our infrastructure. We will use some
> > commands such as `wget` and `rsync` to transfer the test result to
> > our server, but these steps are not included when reproducing locally.
> >
> > Then I come up with an idea that maybe the kernel can boot successfully,
> > but the v3 patch may have some impacts on the command involving network
> > operations.
> >
> > Could you please help to apply below hack on the latest version of
> > lkp-tests, and retry to see if can reproduce the crash? It is just
> > a meaningless `wget` command to involve network in local test and align
> > with the steps in our testing environment.
>
> I will try to repro this this week. I'll let you know what I find.

I applied the wget change you suggested and was able to reproduce the crash.

This is happening because in the case where there is a connect() call
on address 0 on an unbound socket, the socket gets added to the bind
bucket twice. The first happens in inet_bhash2_update_saddr() and the
second happens when __inet_hash_connect() calls inet_bind_hash(). The
fix is to update the bhash2 table only if the socket is already bound.

I will submit v4 with this fix added. There is already a selftest
("sk_connect_zero_addr") in the 3rd patch that simulates this case but
it doesn't trigger the bad page table entry state when unmapping.

Thanks for reporting.

>
> >
> > diff --git a/lib/upload.sh b/lib/upload.sh
> > index 257b498db..e8801736e 100755
> > --- a/lib/upload.sh
> > +++ b/lib/upload.sh
> > @@ -181,7 +181,8 @@ upload_files()
> > fi
> > else
> > # 9pfs, copy directly
> > - upload_files_copy "$@"
> > + wget 127.0.0.1
> > return
> > fi
> > }
> >
> > After applying above hack, I've tried to run 20 times on base and v3 patch
> > respectively. All runs of base are good, but there are 8 crash runs of v3.
> >
> > Reproducing steps:
> >
> > cd linux
> > git remote add net-next https://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git
> > git fetch net-next master
> > git checkout 949d6b405e61 # checkout to base
> > git am <v3.patch>
> >
> > cp config-5.19.0-rc7-01443-g03d56978dd24 .config # config file is attached
> > make ARCH=x86_64 olddefconfig prepare modules_prepare bzImage modules
> > mkdir <mod-install-dir>
> > make ARCH=x86_64 INSTALL_MOD_PATH=<mod-install-dir> modules_install
> > cd <mod-install-dir>
> > find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz
> >
> > git clone https://github.com/intel/lkp-tests.git
> > cd lkp-tests
> > # apply the hack mentioned above
> > bin/lkp qemu -k <bzImage> -m <mod-install-dir>/modules.cgz job-script # job-script is attached in this email
> >
> > --
> > Best Regards,
> > Yujie
> >
> > >
> > > I don't think this bug report is related to the bhash2 changes. But
> > > please let me know if you disagree.
> > >
> > > Thanks,
> > > Joanne
> > >
> > >>
> > >>
> > >> --
> > >> 0-DAY CI Kernel Test Service
> > >> https://01.org/lkp
> > >>
> > >>

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In reply to: Joanne Koong: "Re: [net] 03d56978dd: BUG:Bad_page_map_in_process"
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