From: Andrew Morton <akpm@linux-foundation.org>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Dmitry Vyukov <dvyukov@google.com>,
Hillf Danton <hillf.zj@alibaba-inc.com>,
Michal Hocko <mhocko@suse.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Subject: Re: [PATCH RESEND] mm/hugetlb: Don't call region_abort if region_chg fails
Date: Wed, 29 Mar 2017 14:17:11 -0700 [thread overview]
Message-ID: <20170329141711.50c183a7bb1bfa75e24d4426@linux-foundation.org> (raw)
In-Reply-To: <1490821682-23228-1-git-send-email-mike.kravetz@oracle.com>
On Wed, 29 Mar 2017 14:08:02 -0700 Mike Kravetz <mike.kravetz@oracle.com> wrote:
> Resending because of typo in Andrew's e-mail when first sent
>
> Changes to hugetlbfs reservation maps is a two step process. The first
> step is a call to region_chg to determine what needs to be changed, and
> prepare that change. This should be followed by a call to call to
> region_add to commit the change, or region_abort to abort the change.
>
> The error path in hugetlb_reserve_pages called region_abort after a
> failed call to region_chg. As a result, the adds_in_progress counter
> in the reservation map is off by 1. This is caught by a VM_BUG_ON
> in resv_map_release when the reservation map is freed.
>
> syzkaller fuzzer found this bug, that resulted in the following:
I'll change the above to
: syzkaller fuzzer (when using an injected kmalloc failure) found this bug,
: that resulted in the following:
it's important, because this bug won't be triggered (at all easily, at
least) in real-world workloads.
> kernel BUG at mm/hugetlb.c:742!
> Call Trace:
> hugetlbfs_evict_inode+0x7b/0xa0 fs/hugetlbfs/inode.c:493
> evict+0x481/0x920 fs/inode.c:553
> iput_final fs/inode.c:1515 [inline]
> iput+0x62b/0xa20 fs/inode.c:1542
> hugetlb_file_setup+0x593/0x9f0 fs/hugetlbfs/inode.c:1306
> newseg+0x422/0xd30 ipc/shm.c:575
> ipcget_new ipc/util.c:285 [inline]
> ipcget+0x21e/0x580 ipc/util.c:639
> SYSC_shmget ipc/shm.c:673 [inline]
> SyS_shmget+0x158/0x230 ipc/shm.c:657
> entry_SYSCALL_64_fastpath+0x1f/0xc2
> RIP: resv_map_release+0x265/0x330 mm/hugetlb.c:742
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next prev parent reply other threads:[~2017-03-29 21:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-29 21:08 Mike Kravetz
2017-03-29 21:17 ` Andrew Morton [this message]
2017-03-30 12:28 ` Dmitry Vyukov
2017-03-30 20:20 ` Mike Kravetz
2017-04-10 21:38 ` Vegard Nossum
2017-04-10 23:37 ` Mike Kravetz
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