What led to this crash was an injected memory allocation failure in
media_request_alloc():
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
should_failslab+0x5/0x20
kmem_cache_alloc_trace+0x57/0x300
? anon_inode_getfile+0xe5/0x170
media_request_alloc+0x339/0x440
media_device_request_alloc+0x94/0xc0
media_device_ioctl+0x1fb/0x330
? do_vfs_ioctl+0x6ea/0x1a00
? media_ioctl+0x101/0x120
? __media_device_usb_init+0x430/0x430
? media_poll+0x110/0x110
__se_sys_ioctl+0xf9/0x160
do_syscall_64+0xf3/0x1b0
When that allocation fails, filp->private_data is left uninitialized
which media_request_close() does not expect and crashes.
To avoid this, reorder media_request_alloc() such that
allocating the struct file happens as the last step thus
media_request_close() will no longer get called for a partially created
media request.
Reported-by: syzbot+6bed2d543cf7e48b822b@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi> Fixes: 10905d70d788 ("media: media-request: implement media requests") Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>