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, so 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. Signed-off-by: Yang Wei <Wei.Yang@xxxxxxxxxxxxx> Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/gadget/f_mass_storage.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) Changes in v3 ----> v4 move "new_fsg = common->new_fsg" out of comm->lock protection, and refine the commit log. Thanks Wei diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c index b963939..a7e24c8 100644 --- a/drivers/usb/gadget/f_mass_storage.c +++ b/drivers/usb/gadget/f_mass_storage.c @@ -2342,6 +2342,7 @@ static void handle_exception(struct fsg_common *common) struct fsg_buffhd *bh; enum fsg_state old_state; struct fsg_lun *curlun; + struct fsg_dev *new_fsg; unsigned int exception_req_tag; /* @@ -2460,8 +2461,9 @@ static void handle_exception(struct fsg_common *common) break; case FSG_STATE_CONFIG_CHANGE: - do_set_interface(common, common->new_fsg); - if (common->new_fsg) + new_fsg = common->new_fsg; + do_set_interface(common, new_fsg); + if (new_fsg) usb_composite_setup_continue(common->cdev); break; -- 1.7.9.5 -- 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
