From: Oleg Nesterov <oleg@redhat.com>
To: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: linux-mm <linux-mm@kvack.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Peter Xu <peterx@redhat.com>, Mike Rapoport <rppt@linux.ibm.com>,
Jann Horn <jannh@google.com>, Jason Gunthorpe <jgg@mellanox.com>,
Michal Hocko <mhocko@suse.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [BUG] kernel BUG at fs/userfaultfd.c:385 after 04f5866e41fb
Date: Tue, 27 Aug 2019 18:33:35 +0200 [thread overview]
Message-ID: <20190827163334.GB6291@redhat.com> (raw)
In-Reply-To: <d4583416-5e4a-95e7-a08a-32bf2c9a95fb@huawei.com>
Hi Kefeng,
On 08/13, Kefeng Wang wrote:
>
> Syzkaller reproducer:
> # {Threaded:true Collide:true Repeat:false RepeatTimes:0 Procs:1 Sandbox:none Fault:false FaultCall:-1 FaultNth:0 EnableTun:true EnableNetDev:true EnableNetReset:false EnableCgroups:false EnableBinfmtMisc:true EnableCloseFds:true UseTmpDir:true HandleSegv:true Repro:false Trace:false}
> r0 = userfaultfd(0x80800)
> ioctl$UFFDIO_API(r0, 0xc018aa3f, &(0x7f0000000200))
> ioctl$UFFDIO_REGISTER(r0, 0xc020aa00, &(0x7f0000000080)={{&(0x7f0000ff2000/0xe000)=nil, 0xe000}, 0x1})
> ioctl$UFFDIO_COPY(r0, 0xc028aa03, 0x0)
> ioctl$UFFDIO_COPY(r0, 0xc028aa03, &(0x7f0000000000)={&(0x7f0000ffc000/0x3000)=nil, &(0x7f0000ffd000/0x2000)=nil, 0x3000})
> syz_execute_func(&(0x7f00000000c0)="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")
> poll(&(0x7f00000000c0)=[{}], 0x1, 0x0)
>
> ./syz-execprog -executor=./syz-executor -repeat=0 -procs=16 -cover=0 repofile
I tried to reproduce using the C code provided by Tetsuo but it doesn't work
for me.
Could you run this test-case with the patch below? (on top of the fix you have
already tested).
Oleg.
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -882,6 +882,8 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
unsigned long new_flags;
bool still_valid;
+ file->private_data = (void*)0x6666;
+
WRITE_ONCE(ctx->released, true);
if (!mmget_not_zero(mm))
@@ -1859,6 +1861,8 @@ static long userfaultfd_ioctl(struct file *file, unsigned cmd,
int ret = -EINVAL;
struct userfaultfd_ctx *ctx = file->private_data;
+ BUG_ON(ctx == (void*)0x6666);
+
if (cmd != UFFDIO_API && ctx->state == UFFD_STATE_WAIT_API)
return -EINVAL;
@@ -1882,6 +1886,8 @@ static long userfaultfd_ioctl(struct file *file, unsigned cmd,
ret = userfaultfd_zeropage(ctx, arg);
break;
}
+
+ BUG_ON(ctx != file->private_data);
return ret;
}
next prev parent reply other threads:[~2019-08-27 16:34 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-13 9:08 [BUG] kernel BUG at fs/userfaultfd.c:385 after 04f5866e41fb Kefeng Wang
2019-08-14 13:53 ` Michal Hocko
2019-08-14 14:45 ` Kefeng Wang
2019-08-14 15:10 ` Oleg Nesterov
2019-08-14 15:41 ` Oleg Nesterov
2019-08-15 2:21 ` Kefeng Wang
2019-08-15 9:54 ` Oleg Nesterov
2019-08-16 10:37 ` Kefeng Wang
2019-08-19 12:48 ` Oleg Nesterov
2019-08-19 16:05 ` Andrea Arcangeli
2019-08-20 15:59 ` Oleg Nesterov
2019-08-20 16:15 ` Andrea Arcangeli
[not found] ` <73d7b5b1-a88c-5fca-ba16-be214c2524a4@I-love.SAKURA.ne.jp>
2019-08-20 16:09 ` Oleg Nesterov
2019-08-20 16:02 ` [PATCH] userfaultfd_release: always remove uffd flags and clear vm_userfaultfd_ctx Oleg Nesterov
2019-08-20 16:05 ` Andrea Arcangeli
2019-08-21 0:53 ` Kefeng Wang
2019-08-27 16:33 ` Oleg Nesterov [this message]
2019-08-27 17:14 ` [BUG] kernel BUG at fs/userfaultfd.c:385 after 04f5866e41fb Andrea Arcangeli
2019-08-28 14:25 ` Oleg Nesterov
2019-08-29 12:05 ` Andrea Arcangeli
2019-08-30 16:49 ` Oleg Nesterov
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