From 3137b243c93982fe3460335e12f9247739766e10 Mon Sep 17 00:00:00 2001 From: Tyler Baker Date: Tue, 9 Jun 2026 15:36:34 -0400 Subject: [PATCH] usb: gadget: f_fs: initialize reset_work at allocation time MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ffs_fs_kill_sb() unconditionally calls cancel_work_sync() on ffs->reset_work when a functionfs instance is unmounted: ffs_data_reset(ffs); cancel_work_sync(&ffs->reset_work); However ffs->reset_work is only ever initialized via INIT_WORK() in ffs_func_set_alt() and ffs_func_disable(), and only on the FFS_DEACTIVATED path. That state is reached solely by ffs_data_closed() when the instance is mounted with the "no_disconnect" option, so for the common case (no "no_disconnect", or mounted and unmounted without ever being deactivated) reset_work is never initialized. ffs_data_new() allocates the ffs_data with kzalloc_obj() and does not initialize reset_work, and ffs_data_reset()/ffs_data_clear() do not touch it either, so reset_work.func is left NULL. cancel_work_sync() on such a work then trips the WARN_ON(!work->func) guard in __flush_work(): WARNING: kernel/workqueue.c:4301 at __flush_work+0x330/0x360, CPU#3: umount Call trace: __flush_work cancel_work_sync ffs_fs_kill_sb [usb_f_fs] deactivate_locked_super deactivate_super cleanup_mnt __cleanup_mnt task_work_run exit_to_user_mode_loop el0_svc On older kernels cancel_work_sync() on a zero-initialized work struct was a silent no-op, which hid the missing initialization. Initialize reset_work once in ffs_data_new() so it is always valid for the lifetime of the ffs_data, and drop the now-redundant INIT_WORK() calls from the two deactivation paths. Fixes: 18d6b32fca38 ("usb: gadget: f_fs: add "no_disconnect" mode") Cc: stable Signed-off-by: Tyler Baker Cc: Loic Poulain Cc: Dmitry Baryshkov Cc: Srinivas Kandagatla Tested-by: Loic Poulain Reviewed-by: Peter Chen Acked-by: Michał Nazarewicz Link: https://patch.msgid.link/20260609193635.2284430-1-tyler.baker@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_fs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 7cc446502980..745c44d251f7 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -288,6 +288,7 @@ static int ffs_acquire_dev(const char *dev_name, struct ffs_data *ffs_data); static void ffs_release_dev(struct ffs_dev *ffs_dev); static int ffs_ready(struct ffs_data *ffs); static void ffs_closed(struct ffs_data *ffs); +static void ffs_reset_work(struct work_struct *work); /* Misc helper functions ****************************************************/ @@ -2222,6 +2223,7 @@ static struct ffs_data *ffs_data_new(const char *dev_name) init_waitqueue_head(&ffs->ev.waitq); init_waitqueue_head(&ffs->wait); init_completion(&ffs->ep0req_completion); + INIT_WORK(&ffs->reset_work, ffs_reset_work); /* XXX REVISIT need to update it in some places, or do we? */ ffs->ev.can_stall = 1; @@ -3776,7 +3778,6 @@ static int ffs_func_set_alt(struct usb_function *f, if (ffs->state == FFS_DEACTIVATED) { ffs->state = FFS_CLOSING; spin_unlock_irqrestore(&ffs->eps_lock, flags); - INIT_WORK(&ffs->reset_work, ffs_reset_work); schedule_work(&ffs->reset_work); return -ENODEV; } @@ -3807,7 +3808,6 @@ static void ffs_func_disable(struct usb_function *f) if (ffs->state == FFS_DEACTIVATED) { ffs->state = FFS_CLOSING; spin_unlock_irqrestore(&ffs->eps_lock, flags); - INIT_WORK(&ffs->reset_work, ffs_reset_work); schedule_work(&ffs->reset_work); return; }