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Hillf Danton

2019-Jun-13 14:20 UTC

memory leak in vhost_net_ioctl

Hello Dmitry

On Thu, 13 Jun 2019 20:12:06 +0800 Dmitry Vyukov wrote:> On Thu, Jun 13, 2019 at 2:07 PM Hillf Danton <hdanton at sina.com>
wrote:
> >
> > Hello Jason
> >
> > On Thu, 13 Jun 2019 17:10:39 +0800 Jason Wang wrote:
> > >
> > > This is basically a kfree(ubuf) after the second
vhost_net_flush() in
> > > vhost_net_release().
> > >
> > Fairly good catch.
> >
> > > Could you please post a formal patch?
> > >
> > I'd like very much to do that; but I wont, I am afraid, until I
collect a
> > Tested-by because of reproducer without a cutting edge.
>
> You can easily collect Tested-by from syzbot for any bug with a
reproducer;)
>
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches
>Thank you for the light you are casting.

Here it goes.
--->8--------
From: Hillf Danton <hdanton at sina.com>
Subject: [PATCH] vhost: fix memory leak in vhost_net_release

syzbot found the following crash on:

HEAD commit:    788a0249 Merge tag 'arc-5.2-rc4' of
git://git.kernel.org/p..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?xdc9ea6a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x?c73825cbdc7326
dashboard link: https://syzkaller.appspot.com/bug?extid89f0c7e45efd7bb643
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?xb31761a00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x4892c1a00000


udit: type00 audit(1559768703.229:36): avc:  denied  { map } for
pidq16 comm="syz-executor330"
path="/root/syz-executor330334897"
dev="sda1" ino461
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
executing program
executing program

BUG: memory leak
unreferenced object 0xffff88812421fe40 (size 64):
   comm "syz-executor330", pid 7117, jiffies 4294949245 (age 13.030s)
   hex dump (first 32 bytes):
     01 00 00 00 20 69 6f 63 00 00 00 00 64 65 76 2f  .... ioc....dev/
     50 fe 21 24 81 88 ff ff 50 fe 21 24 81 88 ff ff  P.!$....P.!$....
   backtrace:
     [<00000000ae0c4ae0>] kmemleak_alloc_recursive
include/linux/kmemleak.h:55 [inline]
     [<00000000ae0c4ae0>] slab_post_alloc_hook mm/slab.h:439 [inline]
     [<00000000ae0c4ae0>] slab_alloc mm/slab.c:3326 [inline]
     [<00000000ae0c4ae0>] kmem_cache_alloc_trace+0x13d/0x280
mm/slab.c:3553
     [<0000000079ebab38>] kmalloc include/linux/slab.h:547 [inline]
     [<0000000079ebab38>] vhost_net_ubuf_alloc drivers/vhost/net.c:241
[inline]
     [<0000000079ebab38>] vhost_net_set_backend drivers/vhost/net.c:1534
[inline]
     [<0000000079ebab38>] vhost_net_ioctl+0xb43/0xc10
drivers/vhost/net.c:1716
     [<000000009f6204a2>] vfs_ioctl fs/ioctl.c:46 [inline]
     [<000000009f6204a2>] file_ioctl fs/ioctl.c:509 [inline]
     [<000000009f6204a2>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696
     [<00000000b45866de>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713
     [<00000000dfb41eb8>] __do_sys_ioctl fs/ioctl.c:720 [inline]
     [<00000000dfb41eb8>] __se_sys_ioctl fs/ioctl.c:718 [inline]
     [<00000000dfb41eb8>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718
     [<0000000049c1f547>] do_syscall_64+0x76/0x1a0
arch/x86/entry/common.c:301
     [<0000000029cc8ca7>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88812421fa80 (size 64):
   comm "syz-executor330", pid 7130, jiffies 4294949755 (age 7.930s)
   hex dump (first 32 bytes):
     01 00 00 00 01 00 00 00 00 00 00 00 2f 76 69 72  ............/vir
     90 fa 21 24 81 88 ff ff 90 fa 21 24 81 88 ff ff  ..!$......!$....
   backtrace:
     [<00000000ae0c4ae0>] kmemleak_alloc_recursive 
include/linux/kmemleak.h:55 [inline]
     [<00000000ae0c4ae0>] slab_post_alloc_hook mm/slab.h:439 [inline]
     [<00000000ae0c4ae0>] slab_alloc mm/slab.c:3326 [inline]
     [<00000000ae0c4ae0>] kmem_cache_alloc_trace+0x13d/0x280
mm/slab.c:3553
     [<0000000079ebab38>] kmalloc include/linux/slab.h:547 [inline]
     [<0000000079ebab38>] vhost_net_ubuf_alloc drivers/vhost/net.c:241 
[inline]
     [<0000000079ebab38>] vhost_net_set_backend drivers/vhost/net.c:1534 
[inline]
     [<0000000079ebab38>] vhost_net_ioctl+0xb43/0xc10 
drivers/vhost/net.c:1716
     [<000000009f6204a2>] vfs_ioctl fs/ioctl.c:46 [inline]
     [<000000009f6204a2>] file_ioctl fs/ioctl.c:509 [inline]
     [<000000009f6204a2>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696
     [<00000000b45866de>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713
     [<00000000dfb41eb8>] __do_sys_ioctl fs/ioctl.c:720 [inline]
     [<00000000dfb41eb8>] __se_sys_ioctl fs/ioctl.c:718 [inline]
     [<00000000dfb41eb8>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718
     [<0000000049c1f547>] do_syscall_64+0x76/0x1a0 
arch/x86/entry/common.c:301
     [<0000000029cc8ca7>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

End of syzbot report.

The function vhost_net_ubuf_alloc() appears in the two cases of dump info, for
pid 7130 and 7117, suggesting that it is ubuf leak.

Since commit c38e39c378f4 ("vhost-net: fix use-after-free in
vhost_net_flush")
the function vhost_net_flush() had been no longer releasing ubuf.

Freeing the slab after the last flush in the release path fixes it.


Fixes: c38e39c378f4 ("vhost-net: fix use-after-free in
vhost_net_flush")
Reported-by: Syzbot <syzbot+0789f0c7e45efd7bb643 at
syzkaller.appspotmail.com>
Suggested-by: Jason Wang <jasowang at redhat.com>
Cc: Dmitry Vyukov <dvyukov at google.com>
Cc: Asias He <asias at redhat.com>
Signed-off-by: Hillf Danton <hdanton at sina.com>
---
This is sent only for collecting Tested-by.

 drivers/vhost/net.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 3beb401..22fae0a 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -1404,6 +1404,7 @@ static int vhost_net_release(struct inode *inode, struct
file *f)
 	/* We do an extra flush before freeing memory,
 	 * since jobs can re-queue themselves. */
 	vhost_net_flush(n);
+	kfree(n->vqs[VHOST_NET_VQ_TX].ubufs);
 	kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue);
 	kfree(n->vqs[VHOST_NET_VQ_TX].xdp);
 	kfree(n->dev.vqs);
--

Dmitry Vyukov

2019-Jun-13 14:55 UTC

head link

memory leak in vhost_net_ioctl

On Thu, Jun 13, 2019 at 4:15 PM Hillf Danton <hdanton at sina.com>
wrote:>
>
> Hello Dmitry
>
> On Thu, 13 Jun 2019 20:12:06 +0800 Dmitry Vyukov wrote:
> > On Thu, Jun 13, 2019 at 2:07 PM Hillf Danton <hdanton at
sina.com> wrote:
> > >
> > > Hello Jason
> > >
> > > On Thu, 13 Jun 2019 17:10:39 +0800 Jason Wang wrote:
> > > >
> > > > This is basically a kfree(ubuf) after the second
vhost_net_flush() in
> > > > vhost_net_release().
> > > >
> > > Fairly good catch.
> > >
> > > > Could you please post a formal patch?
> > > >
> > > I'd like very much to do that; but I wont, I am afraid, until
I collect a
> > > Tested-by because of reproducer without a cutting edge.
> >
> > You can easily collect Tested-by from syzbot for any bug with a
reproducer;)
> >
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches
> >
> Thank you for the light you are casting.
:)

But you did not ask syzbot to test. That would be something like this
(keeping syzbot email in CC):

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
master

(I've attached the patch because my email client is incapable of
sending non-corrupted patches inline, but otherwise inline patches
should work too).

> Here it goes.
> --->8--------
> From: Hillf Danton <hdanton at sina.com>
> Subject: [PATCH] vhost: fix memory leak in vhost_net_release
>
> syzbot found the following crash on:
>
> HEAD commit:    788a0249 Merge tag 'arc-5.2-rc4' of
git://git.kernel.org/p..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x dc9ea6a00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x?c73825cbdc7326
> dashboard link: https://syzkaller.appspot.com/bug?extid 89f0c7e45efd7bb643
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x b31761a00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x 4892c1a00000
>
>
> udit: type 00 audit(1559768703.229:36): avc:  denied  { map } for
> pidq16 comm="syz-executor330"
path="/root/syz-executor330334897"
> dev="sda1" ino 461
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
> tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
> executing program
> executing program
>
> BUG: memory leak
> unreferenced object 0xffff88812421fe40 (size 64):
>    comm "syz-executor330", pid 7117, jiffies 4294949245 (age
13.030s)
>    hex dump (first 32 bytes):
>      01 00 00 00 20 69 6f 63 00 00 00 00 64 65 76 2f  .... ioc....dev/
>      50 fe 21 24 81 88 ff ff 50 fe 21 24 81 88 ff ff  P.!$....P.!$....
>    backtrace:
>      [<00000000ae0c4ae0>] kmemleak_alloc_recursive
include/linux/kmemleak.h:55 [inline]
>      [<00000000ae0c4ae0>] slab_post_alloc_hook mm/slab.h:439 [inline]
>      [<00000000ae0c4ae0>] slab_alloc mm/slab.c:3326 [inline]
>      [<00000000ae0c4ae0>] kmem_cache_alloc_trace+0x13d/0x280
mm/slab.c:3553
>      [<0000000079ebab38>] kmalloc include/linux/slab.h:547 [inline]
>      [<0000000079ebab38>] vhost_net_ubuf_alloc
drivers/vhost/net.c:241 [inline]
>      [<0000000079ebab38>] vhost_net_set_backend
drivers/vhost/net.c:1534 [inline]
>      [<0000000079ebab38>] vhost_net_ioctl+0xb43/0xc10
drivers/vhost/net.c:1716
>      [<000000009f6204a2>] vfs_ioctl fs/ioctl.c:46 [inline]
>      [<000000009f6204a2>] file_ioctl fs/ioctl.c:509 [inline]
>      [<000000009f6204a2>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696
>      [<00000000b45866de>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713
>      [<00000000dfb41eb8>] __do_sys_ioctl fs/ioctl.c:720 [inline]
>      [<00000000dfb41eb8>] __se_sys_ioctl fs/ioctl.c:718 [inline]
>      [<00000000dfb41eb8>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718
>      [<0000000049c1f547>] do_syscall_64+0x76/0x1a0
arch/x86/entry/common.c:301
>      [<0000000029cc8ca7>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> BUG: memory leak
> unreferenced object 0xffff88812421fa80 (size 64):
>    comm "syz-executor330", pid 7130, jiffies 4294949755 (age
7.930s)
>    hex dump (first 32 bytes):
>      01 00 00 00 01 00 00 00 00 00 00 00 2f 76 69 72  ............/vir
>      90 fa 21 24 81 88 ff ff 90 fa 21 24 81 88 ff ff  ..!$......!$....
>    backtrace:
>      [<00000000ae0c4ae0>] kmemleak_alloc_recursive 
include/linux/kmemleak.h:55 [inline]
>      [<00000000ae0c4ae0>] slab_post_alloc_hook mm/slab.h:439 [inline]
>      [<00000000ae0c4ae0>] slab_alloc mm/slab.c:3326 [inline]
>      [<00000000ae0c4ae0>] kmem_cache_alloc_trace+0x13d/0x280
mm/slab.c:3553
>      [<0000000079ebab38>] kmalloc include/linux/slab.h:547 [inline]
>      [<0000000079ebab38>] vhost_net_ubuf_alloc
drivers/vhost/net.c:241  [inline]
>      [<0000000079ebab38>] vhost_net_set_backend
drivers/vhost/net.c:1534  [inline]
>      [<0000000079ebab38>] vhost_net_ioctl+0xb43/0xc10 
drivers/vhost/net.c:1716
>      [<000000009f6204a2>] vfs_ioctl fs/ioctl.c:46 [inline]
>      [<000000009f6204a2>] file_ioctl fs/ioctl.c:509 [inline]
>      [<000000009f6204a2>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696
>      [<00000000b45866de>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713
>      [<00000000dfb41eb8>] __do_sys_ioctl fs/ioctl.c:720 [inline]
>      [<00000000dfb41eb8>] __se_sys_ioctl fs/ioctl.c:718 [inline]
>      [<00000000dfb41eb8>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718
>      [<0000000049c1f547>] do_syscall_64+0x76/0x1a0 
arch/x86/entry/common.c:301
>      [<0000000029cc8ca7>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> End of syzbot report.
>
> The function vhost_net_ubuf_alloc() appears in the two cases of dump info,
for
> pid 7130 and 7117, suggesting that it is ubuf leak.
>
> Since commit c38e39c378f4 ("vhost-net: fix use-after-free in
vhost_net_flush")
> the function vhost_net_flush() had been no longer releasing ubuf.
>
> Freeing the slab after the last flush in the release path fixes it.
>
>
> Fixes: c38e39c378f4 ("vhost-net: fix use-after-free in
vhost_net_flush")
> Reported-by: Syzbot <syzbot+0789f0c7e45efd7bb643 at
syzkaller.appspotmail.com>
> Suggested-by: Jason Wang <jasowang at redhat.com>
> Cc: Dmitry Vyukov <dvyukov at google.com>
> Cc: Asias He <asias at redhat.com>
> Signed-off-by: Hillf Danton <hdanton at sina.com>
> ---
> This is sent only for collecting Tested-by.
>
>  drivers/vhost/net.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 3beb401..22fae0a 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -1404,6 +1404,7 @@ static int vhost_net_release(struct inode *inode,
struct file *f)
>         /* We do an extra flush before freeing memory,
>          * since jobs can re-queue themselves. */
>         vhost_net_flush(n);
> +       kfree(n->vqs[VHOST_NET_VQ_TX].ubufs);
>         kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue);
>         kfree(n->vqs[VHOST_NET_VQ_TX].xdp);
>         kfree(n->dev.vqs);
> --
>-------------- next part --------------
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syzbot

2019-Jun-13 18:26 UTC

head link

memory leak in vhost_net_ioctl

Hello,

syzbot has tested the proposed patch but the reproducer still triggered  
crash:
memory leak in vhost_net_ioctl

ANGE): hsr_slave_1: link becomes ready
2019/06/13 18:24:57 executed programs: 18
BUG: memory leak
unreferenced object 0xffff88811cbc6ac0 (size 64):
   comm "syz-executor.0", pid 7196, jiffies 4294943804 (age 14.770s)
   hex dump (first 32 bytes):
     01 00 00 00 81 88 ff ff 00 00 00 00 82 88 ff ff  ................
     d0 6a bc 1c 81 88 ff ff d0 6a bc 1c 81 88 ff ff  .j.......j......
   backtrace:
     [<000000006c752978>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
     [<000000006c752978>] slab_post_alloc_hook mm/slab.h:439 [inline]
     [<000000006c752978>] slab_alloc mm/slab.c:3326 [inline]
     [<000000006c752978>] kmem_cache_alloc_trace+0x13d/0x280
mm/slab.c:3553
     [<00000000b3825d52>] kmalloc include/linux/slab.h:547 [inline]
     [<00000000b3825d52>] vhost_net_ubuf_alloc drivers/vhost/net.c:241  
[inline]
     [<00000000b3825d52>] vhost_net_set_backend drivers/vhost/net.c:1535  
[inline]
     [<00000000b3825d52>] vhost_net_ioctl+0xb43/0xc10  
drivers/vhost/net.c:1717
     [<00000000700f02d7>] vfs_ioctl fs/ioctl.c:46 [inline]
     [<00000000700f02d7>] file_ioctl fs/ioctl.c:509 [inline]
     [<00000000700f02d7>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696
     [<000000009a0ec0a7>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713
     [<00000000d9416323>] __do_sys_ioctl fs/ioctl.c:720 [inline]
     [<00000000d9416323>] __se_sys_ioctl fs/ioctl.c:718 [inline]
     [<00000000d9416323>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718
     [<00000000e4407a23>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:301
     [<000000008715c149>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88810b1365c0 (size 64):
   comm "syz-executor.2", pid 7193, jiffies 4294943823 (age 14.580s)
   hex dump (first 32 bytes):
     01 00 00 00 81 88 ff ff 00 00 00 00 81 88 ff ff  ................
     d0 65 13 0b 81 88 ff ff d0 65 13 0b 81 88 ff ff  .e.......e......
   backtrace:
     [<000000006c752978>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
     [<000000006c752978>] slab_post_alloc_hook mm/slab.h:439 [inline]
     [<000000006c752978>] slab_alloc mm/slab.c:3326 [inline]
     [<000000006c752978>] kmem_cache_alloc_trace+0x13d/0x280
mm/slab.c:3553
     [<00000000b3825d52>] kmalloc include/linux/slab.h:547 [inline]
     [<00000000b3825d52>] vhost_net_ubuf_alloc drivers/vhost/net.c:241  
[inline]
     [<00000000b3825d52>] vhost_net_set_backend drivers/vhost/net.c:1535  
[inline]
     [<00000000b3825d52>] vhost_net_ioctl+0xb43/0xc10  
drivers/vhost/net.c:1717
     [<00000000700f02d7>] vfs_ioctl fs/ioctl.c:46 [inline]
     [<00000000700f02d7>] file_ioctl fs/ioctl.c:509 [inline]
     [<00000000700f02d7>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696
     [<000000009a0ec0a7>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713
     [<00000000d9416323>] __do_sys_ioctl fs/ioctl.c:720 [inline]
     [<00000000d9416323>] __se_sys_ioctl fs/ioctl.c:718 [inline]
     [<00000000d9416323>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718
     [<00000000e4407a23>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:301
     [<000000008715c149>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88810be23700 (size 64):
   comm "syz-executor.3", pid 7194, jiffies 4294943823 (age 14.580s)
   hex dump (first 32 bytes):
     01 00 00 00 00 00 00 00 00 00 00 00 00 c9 ff ff  ................
     10 37 e2 0b 81 88 ff ff 10 37 e2 0b 81 88 ff ff  .7.......7......
   backtrace:
     [<000000006c752978>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
     [<000000006c752978>] slab_post_alloc_hook mm/slab.h:439 [inline]
     [<000000006c752978>] slab_alloc mm/slab.c:3326 [inline]
     [<000000006c752978>] kmem_cache_alloc_trace+0x13d/0x280
mm/slab.c:3553
     [<00000000b3825d52>] kmalloc include/linux/slab.h:547 [inline]
     [<00000000b3825d52>] vhost_net_ubuf_alloc drivers/vhost/net.c:241  
[inline]
     [<00000000b3825d52>] vhost_net_set_backend drivers/vhost/net.c:1535  
[inline]
     [<00000000b3825d52>] vhost_net_ioctl+0xb43/0xc10  
drivers/vhost/net.c:1717
     [<00000000700f02d7>] vfs_ioctl fs/ioctl.c:46 [inline]
     [<00000000700f02d7>] file_ioctl fs/ioctl.c:509 [inline]
     [<00000000700f02d7>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696
     [<000000009a0ec0a7>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713
     [<00000000d9416323>] __do_sys_ioctl fs/ioctl.c:720 [inline]
     [<00000000d9416323>] __se_sys_ioctl fs/ioctl.c:718 [inline]
     [<00000000d9416323>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718
     [<00000000e4407a23>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:301
     [<000000008715c149>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88810b136500 (size 64):
   comm "syz-executor.6", pid 7228, jiffies 4294943827 (age 14.540s)
   hex dump (first 32 bytes):
     01 00 00 00 20 69 6f 63 00 00 00 00 64 65 76 2f  .... ioc....dev/
     10 65 13 0b 81 88 ff ff 10 65 13 0b 81 88 ff ff  .e.......e......
   backtrace:
     [<000000006c752978>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
     [<000000006c752978>] slab_post_alloc_hook mm/slab.h:439 [inline]
     [<000000006c752978>] slab_alloc mm/slab.c:3326 [inline]
     [<000000006c752978>] kmem_cache_alloc_trace+0x13d/0x280
mm/slab.c:3553
     [<00000000b3825d52>] kmalloc include/linux/slab.h:547 [inline]
     [<00000000b3825d52>] vhost_net_ubuf_alloc drivers/vhost/net.c:241  
[inline]
     [<00000000b3825d52>] vhost_net_set_backend drivers/vhost/net.c:1535  
[inline]
     [<00000000b3825d52>] vhost_net_ioctl+0xb43/0xc10  
drivers/vhost/net.c:1717
     [<00000000700f02d7>] vfs_ioctl fs/ioctl.c:46 [inline]
     [<00000000700f02d7>] file_ioctl fs/ioctl.c:509 [inline]
     [<00000000700f02d7>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696
     [<000000009a0ec0a7>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713
     [<00000000d9416323>] __do_sys_ioctl fs/ioctl.c:720 [inline]
     [<00000000d9416323>] __se_sys_ioctl fs/ioctl.c:718 [inline]
     [<00000000d9416323>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718
     [<00000000e4407a23>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:301
     [<000000008715c149>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88810b9cfec0 (size 64):
   comm "syz-executor.7", pid 7236, jiffies 4294943829 (age 14.520s)
   hex dump (first 32 bytes):
     01 00 00 00 20 69 6f 63 00 00 00 00 64 65 76 2f  .... ioc....dev/
     d0 fe 9c 0b 81 88 ff ff d0 fe 9c 0b 81 88 ff ff  ................
   backtrace:
     [<000000006c752978>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
     [<000000006c752978>] slab_post_alloc_hook mm/slab.h:439 [inline]
     [<000000006c752978>] slab_alloc mm/slab.c:3326 [inline]
     [<000000006c752978>] kmem_cache_alloc_trace+0x13d/0x280
mm/slab.c:3553
     [<00000000b3825d52>] kmalloc include/linux/slab.h:547 [inline]
     [<00000000b3825d52>] vhost_net_ubuf_alloc drivers/vhost/net.c:241  
[inline]
     [<00000000b3825d52>] vhost_net_set_backend drivers/vhost/net.c:1535  
[inline]
     [<00000000b3825d52>] vhost_net_ioctl+0xb43/0xc10  
drivers/vhost/net.c:1717
     [<00000000700f02d7>] vfs_ioctl fs/ioctl.c:46 [inline]
     [<00000000700f02d7>] file_ioctl fs/ioctl.c:509 [inline]
     [<00000000700f02d7>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696
     [<000000009a0ec0a7>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713
     [<00000000d9416323>] __do_sys_ioctl fs/ioctl.c:720 [inline]
     [<00000000d9416323>] __se_sys_ioctl fs/ioctl.c:718 [inline]
     [<00000000d9416323>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718
     [<00000000e4407a23>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:301
     [<000000008715c149>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88810b9cd380 (size 64):
   comm "syz-executor.4", pid 7218, jiffies 4294943834 (age 14.470s)
   hex dump (first 32 bytes):
     01 00 00 00 81 88 ff ff 00 00 00 00 81 88 ff ff  ................
     90 d3 9c 0b 81 88 ff ff 90 d3 9c 0b 81 88 ff ff  ................
   backtrace:
     [<000000006c752978>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
     [<000000006c752978>] slab_post_alloc_hook mm/slab.h:439 [inline]
     [<000000006c752978>] slab_alloc mm/slab.c:3326 [inline]
     [<000000006c752978>] kmem_cache_alloc_trace+0x13d/0x280
mm/slab.c:3553
     [<00000000b3825d52>] kmalloc include/linux/slab.h:547 [inline]
     [<00000000b3825d52>] vhost_net_ubuf_alloc drivers/vhost/net.c:241  
[inline]
     [<00000000b3825d52>] vhost_net_set_backend drivers/vhost/net.c:1535  
[inline]
     [<00000000b3825d52>] vhost_net_ioctl+0xb43/0xc10  
drivers/vhost/net.c:1717
     [<00000000700f02d7>] vfs_ioctl fs/ioctl.c:46 [inline]
     [<00000000700f02d7>] file_ioctl fs/ioctl.c:509 [inline]
     [<00000000700f02d7>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696
     [<000000009a0ec0a7>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713
     [<00000000d9416323>] __do_sys_ioctl fs/ioctl.c:720 [inline]
     [<00000000d9416323>] __se_sys_ioctl fs/ioctl.c:718 [inline]
     [<00000000d9416323>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718
     [<00000000e4407a23>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:301
     [<000000008715c149>] entry_SYSCALL_64_after_hwframe+0x44/0xa9



Tested on:

commit:         c11fb13a Merge branch 'for-linus' of
git://git.kernel.org/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11c6b666a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cb38d33cd06d8d48
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11ff0de1a00000

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