From: Vincent Pelletier plr.vincent@gmail.com

Found using DEBUG_ATOMIC_SLEEP while submitting an AIO read operation:

[ 100.853642] BUG: sleeping function called from invalid context at mm/slab.h:421 [ 100.861148] in_atomic(): 1, irqs_disabled(): 1, pid: 1880, name: python [ 100.867954] 2 locks held by python/1880: [ 100.867961] #0: (&epfile->mutex){....}, at: [<f8188627>] ffs_mutex_lock+0x27/0x30 [usb_f_fs] [ 100.868020] #1: (&(&ffs->eps_lock)->rlock){....}, at: [<f818ad4b>] ffs_epfile_io.isra.17+0x24b/0x590 [usb_f_fs] [ 100.868076] CPU: 1 PID: 1880 Comm: python Not tainted 4.14.0-edison+ #118 [ 100.868085] Hardware name: Intel Corporation Merrifield/BODEGA BAY, BIOS 542 2015.01.21:18.19.48 [ 100.868093] Call Trace: [ 100.868122] dump_stack+0x47/0x62 [ 100.868156] ___might_sleep+0xfd/0x110 [ 100.868182] __might_sleep+0x68/0x70 [ 100.868217] kmem_cache_alloc_trace+0x4b/0x200 [ 100.868248] ? dwc3_gadget_ep_alloc_request+0x24/0xe0 [dwc3] [ 100.868302] dwc3_gadget_ep_alloc_request+0x24/0xe0 [dwc3] [ 100.868343] usb_ep_alloc_request+0x16/0xc0 [udc_core] [ 100.868386] ffs_epfile_io.isra.17+0x444/0x590 [usb_f_fs] [ 100.868424] ? _raw_spin_unlock_irqrestore+0x27/0x40 [ 100.868457] ? kiocb_set_cancel_fn+0x57/0x60 [ 100.868477] ? ffs_ep0_poll+0xc0/0xc0 [usb_f_fs] [ 100.868512] ffs_epfile_read_iter+0xfe/0x157 [usb_f_fs] [ 100.868551] ? security_file_permission+0x9c/0xd0 [ 100.868587] ? rw_verify_area+0xac/0x120 [ 100.868633] aio_read+0x9d/0x100 [ 100.868692] ? __fget+0xa2/0xd0 [ 100.868727] ? __might_sleep+0x68/0x70 [ 100.868763] SyS_io_submit+0x471/0x680 [ 100.868878] do_int80_syscall_32+0x4e/0xd0 [ 100.868921] entry_INT80_32+0x2a/0x2a [ 100.868932] EIP: 0xb7fbb676 [ 100.868941] EFLAGS: 00000292 CPU: 1 [ 100.868951] EAX: ffffffda EBX: b7aa2000 ECX: 00000002 EDX: b7af8368 [ 100.868961] ESI: b7fbb660 EDI: b7aab000 EBP: bfb6c658 ESP: bfb6c638 [ 100.868973] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b

Signed-off-by: Vincent Pelletier plr.vincent@gmail.com Signed-off-by: Felipe Balbi felipe.balbi@linux.intel.com Signed-off-by: Siqi Lin siqilin@google.com --- This is a backport of commit 30bf90ccdec1da9c ('usb: gadget: ffs: Forbid usb_ep_alloc_request from sleeping') to 4.4 and 3.18.

drivers/usb/gadget/function/f_fs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 732e6ed5d7b4..39bb65265bff 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -791,7 +791,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) }

if (io_data->aio) { - req = usb_ep_alloc_request(ep->ep, GFP_KERNEL); + req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC); if (unlikely(!req)) goto error_lock;