9p/virtio: Add cleanup path in p9_virtio_init [Linux 4.9.187]

This Linux kernel change "9p/virtio: Add cleanup path in p9_virtio_init" is included in the Linux 4.9.187 release. This change is authored by YueHaibing <yuehaibing [at] huawei.com> on Tue Apr 30 19:59:42 2019 +0800. The commit for this change in Linux stable tree is ea40587 (patch) which is from upstream commit d454854. The same Linux upstream change may have been applied to various maintained Linux releases and you can find all Linux releases containing changes from upstream d454854.

9p/virtio: Add cleanup path in p9_virtio_init

commit d4548543fc4ece56c6f04b8586f435fb4fd84c20 upstream.

KASAN report this:

BUG: unable to handle kernel paging request at ffffffffa0097000
PGD 3870067 P4D 3870067 PUD 3871063 PMD 2326e2067 PTE 0
Oops: 0000 [#1
CPU: 0 PID: 5340 Comm: modprobe Not tainted 5.1.0-rc7+ #25
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
RIP: 0010:__list_add_valid+0x10/0x70
Code: c3 48 8b 06 55 48 89 e5 5d 48 39 07 0f 94 c0 0f b6 c0 c3 90 90 90 90 90 90 90 55 48 89 d0 48 8b 52 08 48 89 e5 48 39 f2 75 19 <48> 8b 32 48 39 f0 75 3a

RSP: 0018:ffffc90000e23c68 EFLAGS: 00010246
RAX: ffffffffa00ad000 RBX: ffffffffa009d000 RCX: 0000000000000000
RDX: ffffffffa0097000 RSI: ffffffffa0097000 RDI: ffffffffa009d000
RBP: ffffc90000e23c68 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa0097000
R13: ffff888231797180 R14: 0000000000000000 R15: ffffc90000e23e78
FS:  00007fb215285540(0000) GS:ffff888237a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffa0097000 CR3: 000000022f144000 CR4: 00000000000006f0
Call Trace:
 v9fs_register_trans+0x2f/0x60 [9pnet
 ? 0xffffffffa0087000
 p9_virtio_init+0x25/0x1000 [9pnet_virtio
 do_one_initcall+0x6c/0x3cc
 ? kmem_cache_alloc_trace+0x248/0x3b0
 do_init_module+0x5b/0x1f1
 load_module+0x1db1/0x2690
 ? m_show+0x1d0/0x1d0
 __do_sys_finit_module+0xc5/0xd0
 __x64_sys_finit_module+0x15/0x20
 do_syscall_64+0x6b/0x1d0
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fb214d8e839
Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01

RSP: 002b:00007ffc96554278 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
RAX: ffffffffffffffda RBX: 000055e67eed2aa0 RCX: 00007fb214d8e839
RDX: 0000000000000000 RSI: 000055e67ce95c2e RDI: 0000000000000003
RBP: 000055e67ce95c2e R08: 0000000000000000 R09: 000055e67eed2aa0
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
R13: 000055e67eeda500 R14: 0000000000040000 R15: 000055e67eed2aa0
Modules linked in: 9pnet_virtio(+) 9pnet gre rfkill vmw_vsock_virtio_transport_common vsock [last unloaded: 9pnet_virtio
CR2: ffffffffa0097000
---[ end trace 4a52bb13ff07b761

If register_virtio_driver() fails in p9_virtio_init,
we should call v9fs_unregister_trans() to do cleanup.

Link: http://lkml.kernel.org/r/[email protected]
Cc: [email protected]
Reported-by: Hulk Robot <[email protected]>
Fixes: b530cc794024 ("9p: add virtio transport")
Signed-off-by: YueHaibing <[email protected]>
Signed-off-by: Dominique Martinet <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

There are 8 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 net/9p/trans_virtio.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index e73fd64..f88911c 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -764,10 +764,16 @@ static void p9_virtio_remove(struct virtio_device *vdev)
 /* The standard init function */
 static int __init p9_virtio_init(void)
 {
+   int rc;
+
    INIT_LIST_HEAD(&virtio_chan_list);

    v9fs_register_trans(&p9_virtio_trans);
-   return register_virtio_driver(&p9_virtio_drv);
+   rc = register_virtio_driver(&p9_virtio_drv);
+   if (rc)
+       v9fs_unregister_trans(&p9_virtio_trans);
+
+   return rc;
 }

 static void __exit p9_virtio_cleanup(void)

Leave a Reply

Your email address will not be published. Required fields are marked *