On Fri, May 22, 2015 at 05:25:18PM +0200, Krzysztof Opasiak wrote:
> Originally FFS_FL_CALL_CLOSED_CALLBACK flag has been used to
> indicate if we should call ffs_closed_callback().
>
> Commit 4b187fceec3c ("usb: gadget: FunctionFS: add devices
> management code") changed its semantic to indicate if we should
> call ffs_closed() function which does a little bit more.
>
> This situation leads to:
>
> [ 122.362269] ------------[ cut here ]------------
> [ 122.362287] WARNING: CPU: 2 PID: 2384 at drivers/usb/gadget/function/f_fs.c:3417 ffs_ep0_write+0x730/0x810 [usb_f_fs]()
> [ 122.362292] Modules linked in:
> [ 122.362555] CPU: 2 PID: 2384 Comm: adbd Tainted: G W 4.1.0-0.rc4.git0.1.1.fc22.i686 #1
> [ 122.362561] Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 07/25/2014
> [ 122.362567] c0d1f947 415badfa 00000000 d1029e64 c0a86e54 00000000 d1029e94 c045b937
> [ 122.362584] c0c37f94 00000002 00000950 f9b313d4 00000d59 f9b2ebf0 f9b2ebf0 fffffff0
> [ 122.362600] 00000003 deb53d00 d1029ea4 c045ba42 00000009 00000000 d1029f08 f9b2ebf0
> [ 122.362617] Call Trace:
> [ 122.362633] [<c0a86e54>] dump_stack+0x41/0x52
> [ 122.362645] [<c045b937>] warn_slowpath_common+0x87/0xc0
> [ 122.362658] [<f9b2ebf0>] ? ffs_ep0_write+0x730/0x810 [usb_f_fs]
> [ 122.362668] [<f9b2ebf0>] ? ffs_ep0_write+0x730/0x810 [usb_f_fs]
> [ 122.362678] [<c045ba42>] warn_slowpath_null+0x22/0x30
> [ 122.362689] [<f9b2ebf0>] ffs_ep0_write+0x730/0x810 [usb_f_fs]
> [ 122.362702] [<f9b2e4c0>] ? ffs_ep0_read+0x380/0x380 [usb_f_fs]
> [ 122.362712] [<c05a1c1f>] __vfs_write+0x2f/0x100
> [ 122.362722] [<c05a42f2>] ? __sb_start_write+0x52/0x110
> [ 122.362731] [<c05a2534>] vfs_write+0x94/0x1b0
> [ 122.362740] [<c0a8a1c0>] ? mutex_lock+0x10/0x30
> [ 122.362749] [<c05a2f41>] SyS_write+0x51/0xb0
> [ 122.362759] [<c0a8c71f>] sysenter_do_call+0x12/0x12
> [ 122.362766] ---[ end trace 0673d3467cecf8db ]---
>
> in some cases (reproduction path below). This commit get back
> semantic of that flag and ensures that ffs_closed() is called
> always when needed but ffs_closed_callback() is called only
> if this flag is set.
>
> Reproduction path:
> Compile kernel without any UDC driver or bound some gadget
> to existing one and then:
>
> $ modprobe g_ffs
> $ mount none -t functionfs mount_point
> $ ffs-example mount_point
>
> This will fail with -ENODEV as there is no udc.
>
> $ ffs-example mount_point
>
> This will fail with -EBUSY because ffs_data has not been
> properly cleaned up.
>
> Signed-off-by: Krzysztof Opasiak <k.opasiak@xxxxxxxxxxx>
adds new sparse warnings:
drivers/usb/gadget/function/f_fs.c:1043:45: warning: incorrect type in argument 1 (different address spaces)
drivers/usb/gadget/function/f_fs.c:1043:45: expected void [noderef] <asn:1>*to
drivers/usb/gadget/function/f_fs.c:1043:45: got void *<noident>
drivers/usb/gadget/function/f_fs.c:205:12: warning: context imbalance in '__ffs_ep0_queue_wait' - unexpected unlock
drivers/usb/gadget/function/f_fs.c:383:17: warning: context imbalance in 'ffs_ep0_write' - different lock contexts for basic block
drivers/usb/gadget/function/f_fs.c:423:24: warning: context imbalance in '__ffs_ep0_read_events' - unexpected unlock
drivers/usb/gadget/function/f_fs.c:429:16: warning: context imbalance in 'ffs_ep0_read' - different lock contexts for basic block
dropped for now.
--
balbi
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