On Fri, 13 Jun 2014, Yang,Wei wrote: > On 06/09/2014 02:19 PM, Wei.Yang@xxxxxxxxxxxxx wrote: > > From: Yang Wei <Wei.Yang@xxxxxxxxxxxxx> > > > > While loading g_mass_storage module, the following warning > > is triggered. > > > > WARNING: at drivers/usb/gadget/composite.c: > > usb_composite_setup_continue: Unexpected call > > Modules linked in: fat vfat minix nls_cp437 nls_iso8859_1 g_mass_storage > > [<800179cc>] (unwind_backtrace+0x0/0x104) from [<80619608>] (dump_stack+0x20/0x24) > > [<80619608>] (dump_stack+0x20/0x24) from [<80025100>] (warn_slowpath_common+0x64/0x74) > > [<80025100>] (warn_slowpath_common+0x64/0x74) from [<800251cc>] (warn_slowpath_fmt+0x40/0x48) > > [<800251cc>] (warn_slowpath_fmt+0x40/0x48) from [<7f047774>] (usb_composite_setup_continue+0xb4/0xbc [g_mass_storage]) > > [<7f047774>] (usb_composite_setup_continue+0xb4/0xbc [g_mass_storage]) from [<7f047ad4>] (handle_exception+0x358/0x3e4 [g_mass_storage]) > > [<7f047ad4>] (handle_exception+0x358/0x3e4 [g_mass_storage]) from [<7f048080>] (fsg_main_thread+0x520/0x157c [g_mass_storage]) > > [<7f048080>] (fsg_main_thread+0x520/0x157c [g_mass_storage]) from [<8004bc90>] (kthread+0x98/0x9c) > > [<8004bc90>] (kthread+0x98/0x9c) from [<8000faec>] (kernel_thread_exit+0x0/0x8) > > > > The root cause is that the existing code fails to take into > > account the possibility that common->new_fsg can change while > > do_set_interface() is running, because the spinlock isn't held > > at this point. > > > > Signed-off-by: Yang Wei <Wei.Yang@xxxxxxxxxxxxx> > > Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > > --- > > drivers/usb/gadget/f_mass_storage.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > Hi Alan, > > > > Thanks for your review, there are a few changes in v3: > > > > 1) Fix a coding style issue. > > 2) Refine the commit log > > > > Regards > > Wei > > Ping, Alan, What do you think of it? You should not have added my "Signed-off-by:"; I did not give you permission to do that. Michal's comment about common->new_fsg not being protected by the lock is a good one. It would be better for the patch description to say: The value of common->new_fsg that gets tested after do_set_interface() returns needs to be the same as the value used by do_set_interface(). With that change, you may add Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
