From: Michal Hocko <mhocko@kernel.org>
To: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
linux-mm@kvack.org, kvm@vger.kernel.org
Subject: Re: KVM hang after OOM
Date: Thu, 15 Mar 2018 13:34:27 +0100 [thread overview]
Message-ID: <20180315123427.GI23100@dhcp22.suse.cz> (raw)
In-Reply-To: <CABXGCsOKkqXTA417GQLE-aj_kYxuQF9W++2HQ=JO-BV3vjCqdQ@mail.gmail.com>
On Mon 12-03-18 23:56:05, Mikhail Gavrilov wrote:
[...]
> [ 355.531533] ============================================
> [ 355.531534] WARNING: possible recursive locking detected
> [ 355.531536] 4.16.0-rc1-amd-vega+ #6 Not tainted
> [ 355.531537] --------------------------------------------
> [ 355.531539] CPU 0/KVM/4034 is trying to acquire lock:
> [ 355.531540] (&mm->mmap_sem){++++}, at: [<0000000026cd8acd>] get_user_pages_unlocked+0xe0/0x1d0
> [ 355.531549]
> but task is already holding lock:
> [ 355.531550] (&mm->mmap_sem){++++}, at: [<000000000690373b>] get_user_pages_unlocked+0x5e/0x1d0
> [ 355.531554]
> other info that might help us debug this:
> [ 355.531555] Possible unsafe locking scenario:
>
> [ 355.531556] CPU0
> [ 355.531557] ----
> [ 355.531558] lock(&mm->mmap_sem);
> [ 355.531559] lock(&mm->mmap_sem);
> [ 355.531561]
> *** DEADLOCK ***
>
> [ 355.531562] May be due to missing lock nesting notation
>
> [ 355.531564] 3 locks held by CPU 0/KVM/4034:
> [ 355.531564] #0: (&vcpu->mutex){+.+.}, at: [<00000000230699e6>] kvm_vcpu_ioctl+0x81/0x6b0 [kvm]
> [ 355.531586] #1: (&kvm->srcu){....}, at: [<000000000a3cc9a1>] kvm_arch_vcpu_ioctl_run+0x752/0x1b90 [kvm]
> [ 355.531602] #2: (&mm->mmap_sem){++++}, at: [<000000000690373b>] get_user_pages_unlocked+0x5e/0x1d0
Is this lockdep report real or a false positive? Because many tasks are
failing to take a mmap_sem. Maybe the same one?
[...]
> [ 615.239436] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> [ 615.239437] pidof D11816 5076 5071 0x00000000
> [ 615.239441] Call Trace:
> [ 615.239443] ? __schedule+0x2e9/0xba0
> [ 615.239446] ? rwsem_down_read_failed+0x147/0x190
> [ 615.239449] schedule+0x2f/0x90
> [ 615.239450] rwsem_down_read_failed+0x118/0x190
> [ 615.239455] ? call_rwsem_down_read_failed+0x14/0x30
> [ 615.239457] call_rwsem_down_read_failed+0x14/0x30
> [ 615.239460] ? proc_pid_cmdline_read+0xd2/0x4a0
> [ 615.239462] down_read+0x97/0xa0
> [ 615.239464] proc_pid_cmdline_read+0xd2/0x4a0
> [ 615.239467] ? lock_acquire+0x9f/0x200
> [ 615.239469] ? debug_check_no_obj_freed+0xda/0x244
> [ 615.239473] ? __vfs_read+0x36/0x170
> [ 615.239475] __vfs_read+0x36/0x170
> [ 615.239479] vfs_read+0x9e/0x150
> [ 615.239482] SyS_read+0x55/0xc0
> [ 615.239484] ? trace_hardirqs_off_thunk+0x1a/0x1c
> [ 615.239487] do_syscall_64+0x7a/0x220
> [ 615.239489] entry_SYSCALL_64_after_hwframe+0x26/0x9b
> [ 615.239491] RIP: 0033:0x7f4d5da16701
> [ 615.239492] RSP: 002b:00007ffd5200b188 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> [ 615.239494] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4d5da16701
> [ 615.239496] RDX: 00000000000007ff RSI: 00007ffd5200b1a0 RDI: 0000000000000004
> [ 615.239497] RBP: 0000000000000042 R08: 0000000000000007 R09: 00007f4d5e1825f4
> [ 615.239498] R10: 0000000000000000 R11: 0000000000000246 R12: 000055abb07f5980
> [ 615.239500] R13: 00007ffd5200b1a0 R14: 0000000000000004 R15: 0000000000000000
> [ 615.239505] INFO: lockdep is turned off.
> [ 639.815026] kworker/dying (149) used greatest stack depth: 10520 bytes left
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-03-15 12:34 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-11 18:11 KVM hang after OOM Mikhail Gavrilov
2018-03-12 9:00 ` Kirill A. Shutemov
2018-03-12 18:56 ` Mikhail Gavrilov
2018-03-13 12:22 ` Tetsuo Handa
2018-03-15 12:34 ` Michal Hocko [this message]
2018-03-15 12:37 ` Michal Hocko
2018-03-12 10:22 ` Tetsuo Handa
2018-03-15 11:56 ` Tetsuo Handa
2018-03-15 20:10 ` Mikhail Gavrilov
2018-03-17 3:13 ` Tetsuo Handa
2018-03-19 16:23 ` Mikhail Gavrilov
2018-03-20 6:53 ` Michal Hocko
2018-03-20 12:20 ` Tetsuo Handa
[not found] ` <CABXGCsNBEpVoMzrhyNLKhzNxPs=9a+Z+2aUxJ8WtZ8gE+=OGSA@mail.gmail.com>
2018-03-22 8:39 ` Michal Hocko
-- strict thread matches above, loose matches on Subject: below --
2018-03-11 16:50 Mikhail Gavrilov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180315123427.GI23100@dhcp22.suse.cz \
--to=mhocko@kernel.org \
--cc=kirill@shutemov.name \
--cc=kvm@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mikhail.v.gavrilov@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.