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| author | Ricardo B. Marliere <ricardo@marliere.net> | 2023-10-13 01:09:12 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@kernel.org> | 2023-11-23 13:35:08 +0100 |
| commit | ded85b0c0edd8f45fec88783d7555a5b982449c1 (patch) | |
| tree | 4f0e11c16e038e9fee3e1a9b4b34c8fa1e566db7 /drivers/media/usb | |
| parent | 0cb8c9482501c46854ddb3d43b1bc05d771b9624 (diff) | |
| download | lwn-ded85b0c0edd8f45fec88783d7555a5b982449c1.tar.gz lwn-ded85b0c0edd8f45fec88783d7555a5b982449c1.zip | |
media: pvrusb2: fix use after free on context disconnection
Upon module load, a kthread is created targeting the
pvr2_context_thread_func function, which may call pvr2_context_destroy
and thus call kfree() on the context object. However, that might happen
before the usb hub_event handler is able to notify the driver. This
patch adds a sanity check before the invalid read reported by syzbot,
within the context disconnection call stack.
Reported-and-tested-by: syzbot+621409285c4156a009b3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000a02a4205fff8eb92@google.com/
Fixes: e5be15c63804 ("V4L/DVB (7711): pvrusb2: Fix race on module unload")
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Acked-by: Mike Isely <isely@pobox.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Diffstat (limited to 'drivers/media/usb')
| -rw-r--r-- | drivers/media/usb/pvrusb2/pvrusb2-context.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/media/usb/pvrusb2/pvrusb2-context.c b/drivers/media/usb/pvrusb2/pvrusb2-context.c index 14170a5d72b3..1764674de98b 100644 --- a/drivers/media/usb/pvrusb2/pvrusb2-context.c +++ b/drivers/media/usb/pvrusb2/pvrusb2-context.c @@ -268,7 +268,8 @@ void pvr2_context_disconnect(struct pvr2_context *mp) { pvr2_hdw_disconnect(mp->hdw); mp->disconnect_flag = !0; - pvr2_context_notify(mp); + if (!pvr2_context_shutok()) + pvr2_context_notify(mp); } |